June 2022   |   Volume 20   |   Issue 4

Pathogen Profile: Staphylococcus Pseudintermedius

in this issue

in this issue

Staphylococcus pseudintermedius

Metatarsal Draining Tract in a German Shepherd Dog

Incisional Wedge Biopsy of Subcutaneous Tumors

Acute Gastroenteritis in Dogs

Differential Diagnosis: Peripheral Lymphadenopathy in Cats

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Metatarsal Draining Tract in a German Shepherd Dog

Danielle R. Tulloss, DVM, DACVPM, Dermatology Clinic for Animals, US Army Reserves, Lacey, Washington

Danielle N. Wyatt, DVM, DACVD, Dermatology Clinic for Animals, Lacey, Washington

Kimberly Coyner*, DVM, DACVD, Formerly of Dermatology Clinic for Animals, Lacey, Washington

Dermatology

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Metatarsal Draining Tract in a German Shepherd Dog

Clinical History & Signalment

Remi, a 4-year-old spayed German shepherd dog, was presented to a dermatology referral clinic for evaluation of a unilateral draining tract proximal to the right metatarsal pad of 4 months’ duration. The draining tract was not pruritic and only noted after blood-tinged spots were occasionally seen on the floor of the home. The discharge was reported to originate from the draining lesion on the right pelvic limb, and the owner did not believe the lesion had changed over time. 

Remi lived primarily indoors with access to a fenced yard. She was housemates with another dog and a cat; both were unaffected. Remi was otherwise apparently healthy, and no lameness or discomfort of the area had been observed. Vaccinations and flea, tick, and heartworm preventives were current. 

The referring clinician performed cytology of the right metatarsal exudate that revealed scattered extracellular cocci bacteria with pyogranulomatous inflammation, and cefpodoxime (5 mg/kg PO every 24 hours) was administered for 21 days with no improvement. Routine CBC and serum chemistry profile were unremarkable. Orthopedic examination was within normal limits; radiography was thus performed, and results were normal. Subsequent surgical exploration by the referring clinician revealed no foreign body inside the wound, but a subcutaneous sinus extending ≈1.5 cm proximally was found. Enrofloxacin (5 mg/kg PO every 24 hours) and carprofen (2.2 mg/kg PO every 12 hours) were administered for 14 days with no improvement. Bacterial cultures were not collected.

Remi was referred to the dermatology clinic for evaluation. 

Physical Examination

On presentation at the dermatology referral clinic, Remi was bright, alert, and responsive. Vital signs were within normal limits. BCS was 4/9, pain score was 0/4, and muscle condition score was adequate. 

Dermatologic examination revealed matted fur, indurated and inflamed skin, and several small draining tracts with serous discharge on the right ventral metatarsus extending ≈6 cm proximal to the metatarsal pad (Figure 1). The left metatarsal region was also mildly affected, and there was a focal area of fistulation, hypotrichosis, hyperemia, and edema of the skin proximal to the left metatarsal pad (Figure 2). Scattered areas of pinpoint erosions were also present.

Area on the right pelvic limb proximal to the metatarsal pad characterized by matted fur; indurated, erythematous, edematous skin; and multifocal chronic fistulae (circles) surrounded by serous discharge 
Area on the right pelvic limb proximal to the metatarsal pad characterized by matted fur; indurated, erythematous, edematous skin; and multifocal chronic fistulae (circles) surrounded by serous discharge 

FIGURE 1 Area on the right pelvic limb proximal to the metatarsal pad characterized by matted fur; indurated, erythematous, edematous skin; and multifocal chronic fistulae (circles) surrounded by serous discharge 

FIGURE 1 Area on the right pelvic limb proximal to the metatarsal pad characterized by matted fur; indurated, erythematous, edematous skin; and multifocal chronic fistulae (circles) surrounded by serous discharge 

Lesion on the left pelvic limb proximal to the metatarsal pad with a draining fistula (circle), erythema, hypotrichosis, and superficial erosions
Lesion on the left pelvic limb proximal to the metatarsal pad with a draining fistula (circle), erythema, hypotrichosis, and superficial erosions

FIGURE 2 Lesion on the left pelvic limb proximal to the metatarsal pad with a draining fistula (circle), erythema, hypotrichosis, and superficial erosions

FIGURE 2 Lesion on the left pelvic limb proximal to the metatarsal pad with a draining fistula (circle), erythema, hypotrichosis, and superficial erosions

Diagnosis

Cytologic examination of right and left limb lesions revealed pyogranulomatous inflammation characterized by neutrophils, macrophages that were often multinucleate with foamy cytoplasm, and smaller numbers of plasma cells and lymphocytes; no infectious organisms were seen. A deep skin scraping was negative for mites.

A full-thickness punch biopsy of affected tissue under local anesthetic was performed; results revealed a deep pyogranulomatous, nodular-to-diffuse dermatitis and panniculitis with fibrosis and fistulous tracts. The infiltrate contained neutrophils, macrophages, plasma cells, and lymphocytes. Periodic acid-Schiff, acid-fast, and Gram stains were negative for fungal and bacterial organisms, and tissue cultures for aerobic and anaerobic bacteria and fungi were negative. No demodectic mites or other parasites were identified on biopsy.

DIAGNOSIS:

BILATERAL METATARSAL FISTULAE

Treatment & Long-Term Management

Bilateral metatarsal fistulae were suspected, and treatment was initiated according to current recommendations, pending biopsy results.1 There was a 30-day washout period between administration of carprofen and prednisone. An anti-inflammatory dose of prednisone (1 mg/kg PO every 24 hours for 7 days) was administered due to the high index of suspicion for bilateral metatarsal fistulae.1 Rapid improvement of lesions resulted. Prednisone was reduced to 1 mg/kg every 48 hours beginning on day 8, but lesions worsened by day 14. 

On day 14, topical tacrolimus 0.1% ointment was initiated every 12 hours for 14 days; marked reduction in edema occurred after topical tacrolimus was added to the management plan, and tacrolimus allowed for furthering tapering of prednisone. On day 28, prednisone was reduced to 1 mg/kg PO every 72 hours for 3 doses, then stopped. Topical tacrolimus was simultaneously reduced to once every 24 hours and administered for an additional 21 days. 

Metatarsal fistulae were resolved at the 8-week recheck, and topical tacrolimus was tapered to every 48 hours for 30 days, then twice weekly for 30 days, and discontinued on day 118.

TREATMENT-AT-A-GLANCE

  • Sole therapy with 0.1% tacrolimus topical ointment every 12 hours may lead to remission after 3 to 6 weeks and can be tapered to once every 24 hours, followed by alternate-day therapy3,4; treatment can be discontinued in some patients. 
  • Some dogs require oral immunomodulatory therapy. It is often recommended to start with prednisone (1 mg/kg PO every 24 hours, tapered to a maintenance regimen of, ideally, 0.25-0.5 mg/kg PO 1-2 times per week) or cyclosporine (5 mg/kg PO every 24 hours, tapered to the lowest frequency that maintains remission after 4-6 weeks of treatment).1,5-7 Lesions may relapse at less-frequent intervals of administration without additional topical therapy (eg, tacrolimus, oral steroid-sparing drugs).1,5-7
  • Vitamin E (200-300 IU every 12 hours) has been used to reduce the maintenance dosage of glucocorticoids.6
  • Systemic antibiotic treatment may improve lesions with secondary bacterial infection but does not lead to resolution.2
  • Bilateral metatarsal fistulae are suspected to be immune-mediated, and surgical excision of fistulae is not curative; lesions recur weeks to months later.2,3

Prognosis & Outcome

Lesions were resolved 8 weeks after treatment was started. Remi was still in complete remission 2 months later, and bilateral metatarsal fistulae had not recurred after 6 months. 

Prognosis for metatarsal fistulae is excellent with appropriate medical management. Immunomodulatory or immunosuppressive therapy often leads to long-term remission but may be required chronically. Lesions typically persist when left untreated and do not respond to surgical removal alone. Spontaneous remission is possible but rare.2

TAKE-HOME MESSAGES

  • Metatarsal and metacarpal fistulae (focal metatarsal/metacarpal fistulation, sterile pedal panniculitis) are uncommon and usually seen in adult German shepherd dogs and their crossbreeds but have been reported sporadically in rottweilers, Weimaraners, and greyhounds.2,3,5,6 To the authors’ knowledge, metatarsal fistulae are not associated with other immune-mediated fistula syndromes (eg, perianal fistulae, which are commonly seen in German shepherd dogs).1 
  • Both pelvic limbs are typically involved, and lesions are idiopathic, yet pathognomonic, in German shepherd dogs.1 Lesions are infrequently unilateral, and thoracic limbs are occasionally affected along the caudal metacarpal region just proximal to the metacarpal pads.1,2 In many patients, lesions are striking, and additional investigation is often not warranted; however, chronic metatarsal fistulae can appear ulcerated, edematous, and crusted. Because the condition is chronic, there are many differentials, including infectious, immune-mediated, neoplastic, and idiopathic causes.1 In this patient, infectious organisms were not identified on aerobic culture or histopathology, supporting the diagnosis of bilateral metatarsal fistulae. Although the presentation of bilateral metatarsal fistulae is often straightforward, this is not always the case for chronic conditions, and additional infectious and immune-mediated causes should be ruled out before immunomodulatory or immunosuppressive treatments are initiated.1
  • Differential diagnoses for unilateral lesions include foreign bodies, puncture wounds, and deep bacterial or fungal infections.1,2,5,7
  • Acute lesions appear as fluctuant swellings or edema along the central plantar surface of the metatarsus just proximal to the metatarsal pad, progressing to well-demarcated fistulae with serosanguinous discharge.5 Lesions do not usually seem to affect dogs, and pet owners typically only notice lesions when the patient licks the skin or bloody spots appear on the floor.1
  • Etiology and mechanism of this condition are unknown, but an immune-mediated process may be responsible.2,5 Strong breed predisposition implies heritability.1,7
  • Bilateral metatarsal fistulae are generally chronic and do not tend to spontaneously regress, but the disease is usually responsive to immunomodulatory and immunosuppressive medications. Some patients may stay in remission once treatment is completed; others may require lifelong management.5

References

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Digital Edition may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.


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Staphylococcus pseudintermedius

J. Scott Weese, DVM, DVSc, DACVIM, FCAHS, Ontario Veterinary College, Ontario, Canada

Infectious Disease

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<em>Staphylococcus pseudintermedius</em>

Staphylococcus pseudintermedius (previously called S intermedius), a gram-positive bacterium, is a leading cause of opportunistic infections, particularly of the skin and soft tissue, in dogs and cats and is predominantly found on mucosal surfaces.1 Infections typically occur after normal host defenses are compromised, particularly via damage to the skin barrier.

Organism

S pseudintermedius is a coagulase-positive Staphylococcus spp found in the mucosal and skin microbiotas of up to 85% of healthy dogs2-5; however, comprehensive testing may find it in nearly all dogs. Although there are few studies on S pseudintermedius in cats, rates of 9% to 22% have been reported.6,7

Antimicrobial Resistance

S pseudintermedius is potentially susceptible to most antimicrobials but easily develops resistance to many antimicrobials. Beta-lactamase–mediated resistance to penicillins (eg, amoxicillin) is common.2,8 Methicillin resistance associated with resistance to penicillins, cephalosporins, and carbapenems is a significant concern, particularly in dogs.

Methicillin-resistant S pseudintermedius (MRSP) is resistant to many drug classes and can be found in healthy dogs and cats (prevalence of 0%-9% in dogs and <1% in cats).9-16 Primary risk factors for infection with MRSP include recent antimicrobial use, previous MRSP infection, and previous hospitalization or visit to the clinic.17-19 Prolonged colonization with MRSP can be observed in some dogs, as S pseudintermedius is a canine commensal, resulting in potential infection with the bacterium for months after successful clinical cure.20

Disease

S pseudintermedius can cause opportunistic infections in almost any organ system, is the predominant cause of superficial folliculitis (eg, pyoderma), and is a common (possibly the most common) cause of wound and surgical site infections.21-26 Disease can range from mild and self-limiting to rapidly fatal, depending on infection location (eg, skin infection vs sepsis) and patient factors (eg, immunocompetence).

Diagnosis

Culture and susceptibility testing of appropriate specimens is required for definitive diagnosis of staphylococcal infection. Adjunct testing, including cytology (eg, identification of cocci in neutrophils), can support culture results and clinical suspicion in lieu (or in advance) of culture. Methicillin resistance is detected via routine antimicrobial susceptibility testing. Oxacillin is most commonly used as the marker of methicillin resistance; cefoxitin can also be used. Resistance to oxacillin or cefoxitin indicates MRSP. Resistance to amoxicillin/clavulanic acid or cephalosporins indicates strong suspicion of methicillin resistance.

Treatment

Certain types of topical therapy can be effective for treatment of superficial infections and is a first-line option.22 Chlorhexidine bathing is an effective alternative to systemic antimicrobials in dogs with superficial folliculitis and has been recommended as a first-line treatment.22 Other topical agents (eg, benzoyl peroxide) have less supporting evidence but may be effective in some situations.27,28 Topical biocides or antimicrobials (eg, mupirocin, fusidic acid) can be effective for treatment of other superficial (eg, wound) infections. In vitro studies have suggested additional treatments (eg, honey) may also be useful.29

Drug choice should ideally be based on susceptibility testing when systemic antimicrobials are required. Penicillins (eg, amoxicillin) are highly effective against susceptible strains, but beta-lactamase–producing species are common in many regions. Empirical treatment with a potentiated penicillin (eg, amoxicillin/clavulanic acid), clindamycin, or first-generation cephalosporin (eg, cephalexin) is reasonable when MRSP is not considered highly likely (eg, no previous MRSP infection or recent antibiotic treatment). Doxycycline and potentiated sulfonamides are also effective antistaphylococcal drugs. Fluoroquinolones and third-generation cephalosporins have activity against staphylococci but are preferred for use against gram-negative bacteria, and use of these higher-tier antibiotics offers little to no benefit compared with other options, except in patients in which once-daily or single-injection administration is required. 

Treatment options for MRSP are usually limited and should be guided by susceptibility testing. MRSP is typically susceptible to amikacin and chloramphenicol, but resistance can occur. Chloramphenicol should be used with caution in cats. Nitrofurantoin can be useful for treatment of lower urinary tract disease. Fosfomycin can be used in dogs but is toxic in cats.30 Rarely, higher-tier drugs (eg, linezolid) can be considered but should be reserved for cases in which there are no other options, treatment has a good chance of success, and an expert in infectious diseases or clinical pharmacology has been consulted. Because staphylococcal infections are almost invariably secondary, underlying causes (eg, allergic skin disease) should be addressed concurrently when possible.

Prevention

Because S pseudintermedius can cause opportunistic infection, the goal of preventive treatment for MRSP and methicillin-susceptible strains is to reduce the risk for secondary infection by controlling underlying risk factors (eg, allergic skin disease), using surgical asepsis, and providing good wound care.

Zoonotic Risks

S pseudintermedius is potentially zoonotic, but the risks are low. Human infections with methicillin-susceptible S pseudintermedius and MRSP have been reported31-35; however, the relatively ubiquitous nature of S pseudintermedius in dogs, high human-to-dog exposure, and rarely reported infections of methicillin-susceptible S pseudintermedius and MRSP indicate that risks are limited. There is no evidence or suspicion that MRSP has greater risk for transmission to humans. Good hygiene (particularly hand hygiene) and avoiding contact with infected sites can help prevent zoonotic transmission.

References

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Digital Edition may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.


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Differential Diagnosis: Peripheral Lymphadenopathy in Cats

Ann Hohenhaus, DVM, DACVIM (SAIM, Oncology), The Schwarzman Animal Medical Center, New York, New York

Internal Medicine

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Differential Diagnosis: Peripheral Lymphadenopathy in Cats

Following are differential diagnoses for cats presented with peripheral lymphadenopathy.

  • Neoplastic
    • Lymphoproliferative
      • Lymphoma
        • T-cell-rich B-cell lymphoma1 
        • Hodgkin-like lymphoma2
    • Metastatic neoplasia (common causes)
      • Carcinoma (eg, mammary gland carcinoma, oral squamous cell carcinoma)
      • Mast cell tumor
  • Reactive
    • Infectious 
      • Systemic fungal infection
        • Blastomycosis (Blastomyces dermatitidis)
        • Histoplasmosis (Histoplasma capsulatum)
        • Coccidioidomycosis (Coccidioides immitis)
        • Cryptococcosis (Cryptococcus neoformans)
        • Sporotrichosis (Sporothrix schenckii)
      • Mycobacteriosis (Mycobacterium avium complex; Mycobacterium bovis, Mycobacterium microti-like)
      • Vector-borne disease (coinfection is common) 
        • Ehrlichiosis (Ehrlichia spp)
        • Cytauxzoonosis (Cytauxzoon felis)
        • Leishmaniasis3 (Leishmania spp)
        • Tularemia4 (Francisella tularensis)
        • Hepatozoonosis (Hepatozoon spp)
        • Plague (Yersinia pestis)
        • Bartonellosis (Bartonella henselae)
      • Toxoplasmosis (Toxoplasma gondii)
      • Hemotrophic mycoplasma5 (Mycoplasma spp)
      • Retrovirus 
        • FeLV
        • FIV
  • Inflammatory or immune related 
    • Autoimmune lymphoproliferative syndrome of British shorthair cats
  • Drug reaction
    • Phenobarbital-induced pseudolymphoma
    • Zonisamide-induced lymphadenopathy8 
    • Methimazole
  • Idiopathic
    • Plexiform vasculopathy of cervical or inguinal lymph nodes10
    • Generalized lymphadenopathy resembling lymphoma11
    • Distinctive peripheral lymph node hyperplasia of young cats12

References

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Digital Edition may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.


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Acute Gastroenteritis in Dogs

Amanda A. Cavanagh, DVM, DACVECC, Colorado State University

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Acute Gastroenteritis in Dogs

CRT = capillary refill time, GDV = gastric dilatation-volvulus, MM = mucous membrane, PCV = packed cell volume, TS = total solids

References

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Digital Edition may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.


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Clinical Notes: Optimizing Phosphorus Control in Chronic Kidney Disease

Clinical Notes: Optimizing Phosphorus Control in Chronic Kidney Disease

Dennis Chew, DVM, DACVIM, The Ohio State University

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Clinical Notes: Optimizing Phosphorus Control in Chronic Kidney Disease
Sponsored by an Unrestricted Educational Grant from Nutramax Laboratories Veterinary Sciences, Inc.

KEY POINTS

  • Progression of renal disease and decreased survival times are associated with hyperphosphatemia.
  • Renal diets are often recommended at the onset of kidney disease, but the addition of phosphate binder supplements can potentially minimize disease progression.
  • Intestinal phosphate binders for dogs and cats are frequently underutilized.
  • Naraquin™ is formulated to provide a balanced approach to phosphorus binding, with a proprietary blend of 3 phosphate binders: ferric citrate, calcium acetate, and chitosan.
  • The omega-3 fatty acids and β-glucans found within Naraquin™ are designed to support renal health.
  • Evaluated in healthy cats on a maintenance diet, Naraquin™ has demonstrated the ability to reduce urine phosphorus levels.

Chronic kidney disease (CKD) is the most frequent cause of hyperphosphatemia in adult dogs and cats, as phosphorus retention occurs due to impaired renal phosphate excretion.1 Hyperphosphatemia is associated with CKD progression and decreased survival.2

In early stages of CKD (IRIS stage 1),3 serum phosphorus remains within the reference range due to compensatory increases in the secretion of parathyroid hormone (PTH) and fibroblast growth factor-23 (FGF-23). In advanced stages of CKD, serum phosphorus can increase above the reference range as compensatory changes are overwhelmed.

Circulating phosphorus concentrations depend on dietary phosphorus intake, GI absorption, translocation into intracellular sites, skeletal resorption, and urinary phosphorus excretion.1 The kidneys are crucial in regulating circulating phosphorus concentrations within a narrow range.4 The typical reference range for phosphorus is 2.5-5.5 mg/dL (0.8-1.8 mmol/L) for mature dogs and 2.5-6 mg/dL (0.8-1.9 mmol/L) for cats.5

Methods for Reducing Total Body Phosphate Burden

Decreasing GI absorption of dietary phosphorus decreases total body phosphate burden. Diets with lower phosphorus content (mg/100 kcal), diets with decreased phosphate bioavailability, and the addition of intestinal phosphate binders can help decrease phosphate.6,7 Although dietary phosphorus restrictions can be effective initially, phosphate binder supplements can be a critical addition or replacement for renal diets.8,9

Intestinal Phosphate-Binding Agents

Phosphate-binding agents trap phosphorus in the gut and increase insoluble phosphate salt excretion through the feces.8 Intestinal phosphate binders work best when given with food or within 2 hours of feeding.10 Administration should be based on meal size (ie, phosphorus intake) and individual serum phosphorus levels and titrated to effect.1,10 Achieving mid-reference range target phosphate concentrations can be challenging in those with higher levels of azotemia due to severe decreases in GFR and phosphorus retention.

Although dietary phosphorus restrictions can be effective initially, phosphate binder supplements can be a critical addition or replacement for renal diets.

Aluminum-Containing Binders

Aluminum salts are frequently used in phosphate binding. Citrate salts, however, enhance aluminum absorption and should be avoided.11 Some dogs with azotemic CKD treated with aluminum salts have been shown to have mean circulating aluminum concentrations significantly higher than the reference range, with some dogs showing neuromuscular signs2,12-14; in these dogs, progressive decline in mean corpuscular volume and mean corpuscular hemoglobin was a sensitive and specific biomarker for aluminum accumulation.14,15 Aluminum toxicity may be of more concern in cats due to their longer survival times, but this has yet to be reported. Constipation is a common adverse effect.

Iron-Containing Binders

Iron-based phosphate binders can potentially correct anemia and decrease circulating phosphorus.16 Ferric citrate can be helpful in phosphate binding and correcting anemia in humans with CKD.17-19 Although traditional oral iron preparations are associated with frequent adverse GI effects and poor intestinal absorption,18 ferric citrate is well tolerated in humans with CKD, with significant intestinal absorption of iron.16 Discolored stool and constipation are the most common adverse effects.16,17

Studies have shown that ferric citrate can help reduce hyperphosphatemia.18 An iron oxide/hydroxide insoluble complex was developed for cats as an oral intestinal phosphate binder20,21; when added to maintenance food and fed to healthy cats in a study,21 urine phosphate concentration was significantly decreased, increased urine phosphate excretion was apparent, and fractional excretion of phosphate into urine developed in a dose-dependent manner. In healthy cats, significant decreases in serum phosphate, urinary phosphate, and urinary fractional phosphate excretion were observed in those treated with a renal diet supplemented with iron oxide/ hydroxide. This iron-supplemented diet also resulted in more significantly reduced serum and urine phosphate concentrations than did the lanthanum-supplemented control group.21

Calcium-Containing Binders

Although their binding capacity is lower than aluminum salts, calcium-based salts have been used to avoid aluminum exposure.10 Calcium carbonate binds phosphorus best in an acidic environment (pH, ≈5), with binding capacity reduced in the neutral pH range.22 Calcium acetate, however, can bind phosphate over a wide range of pH levels and has greater phosphate binding capacity than calcium carbonate, reducing administration and the potential for hypercalcemia. Advantages of calcium salts include low costs and mitigation of hypocalcemia.23 GI upset and constipation are common adverse effects.11 When calcium-containing binders are used, ionized calcium concentration should be monitored, and use with calcitriol may be restricted.

Other Phosphate Binders

Chitosan, a nonabsorbable polysaccharide, can decrease oxidative stress, PTH, and phosphate serum markers in dialysis patients.23 A combination of chitosan and 10% calcium carbonate has been shown to successfully decrease serum phosphorus in cats with early CKD.24,25

A multi-ingredient oral supplement designed to provide intestinal phosphate-binding from ferric citrate, calcium acetate, and chitosan currently marketed in the US for use in dogs and cats (Naraquin™) demonstrated positive results in a pilot study.26 Omega-3 fatty acids and β-glucans are included for additional renal benefits. In this study, urinary phosphate concentration significantly declined at 1 and 4 weeks of administration in healthy cats.26

A multi-ingredient oral supplement designed to provide intestinal phosphate-binding from ferric citrate, calcium acetate, and chitosan currently marketed in the US for use in dogs and cats (Naraquin™) demonstrated positive results in a pilot study.

Sevelamer is a commonly used non-calcium–based phosphate binder but has a lower phosphate-binding capacity than other binders.11 Effects of this binder in dogs and cats with CKD have not been reported. GI intolerance and high costs are some disadvantages.

Lanthanum carbonate is another non-aluminum and non-calcium intestinal phosphate binder.10 Lanthanum’s affinity for intestinal phosphate binding is similar to aluminum and about twice that of sevelamer or calcium-based binders.27

Toxicity studies in dogs have shown that lanthanum accumulates at low concentrations in many tissues (eg, GI, bone, liver) and has been studied extensively in normal and azotemic CKD cats. It is an excellent binder, with minimal to no recognized toxicity in cats28-35; however, expense can limit its use.

Conclusion

Dietary phosphate restriction is considered standard of care for dogs and cats with IRIS CKD stages 2 through 4. Serum phosphorus concentrations should be measured in CKD patients after 4 to 6 weeks of feeding a reduced phosphorus diet or starting a phosphate binder.

Some cats with CKD can develop total, ionized hypercalcemia during the long-term feeding of highly restricted phosphate renal diets. Thus, it is essential to measure ionized calcium when phosphorus is measured. If a patient is stable and the desired targeted circulating phosphorus levels have been reached, evaluating a renal panel that includes phosphorus and calcium is recommended every 3 to 4 months. Increased calcium trends can indicate too little phosphorus available in the gut lumen, favoring absorption of too much calcium into circulation, which is more likely to develop in cats with early- stage CKD.36-40

With many different phosphate binders available to choose from, it is important to have an understanding of the pros and cons of each option. Cost, adverse effects, and efficacy all play into the most appropriate choice for a patient. As new phosphate binders come to market, available options continue to expand, allowing for appropriately addressing and managing secondary issues in patients with CKD.

References

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Digital Edition may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.


Malassezia pachydermatis Sensitivity in Dogs with Atopic Dermatitis

Darin Dell, DVM, DACVD, Wheat Ridge Animal Hospital, Wheat Ridge, Colorado

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<em>Malassezia pachydermatis</em> Sensitivity in Dogs with Atopic Dermatitis

In the Literature

Ishimaru H, Okamoto N, Fujimura M, et al. IgE sensitivity to Malassezia pachydermatis and mite allergens in dogs with atopic dermatitis. Vet Immunol Immunopathol. 2020;226:110070.


FROM THE PAGE…

Malassezia pachydermatis are normal commensal organisms found on the skin of dogs, typically in the ears and near mucous membranes. Malassezia spp dermatitis describes skin infection caused by M pachydermatis, is common in all allergic dogs, and can occur in dogs with or without M pachydermatis hypersensitivity.

This study evaluated atopic (n = 15) and food allergic (n = 37) dogs to determine how many in each group were hypersensitive to M pachydermatis. Serum immunoglobulin E (IgE) measurement and intradermal allergen testing were used following standard protocols.

Results indicated that dogs with nonfood-induced atopic dermatitis were more likely to be hypersensitive to M pachydermatis than dogs with food-induced atopic dermatitis: 60% of dogs with nonfood-induced atopic dermatitis demonstrated M pachydermatis hypersensitivity via IgE testing, and results were slightly higher (73%) with intradermal allergy testing. IgE and intradermal allergy testing both revealed that 16% of dogs with food-induced atopic dermatitis were hypersensitive to M pachydermatis.

The authors hypothesized that the difference between the 2 groups was due to a faulty epidermal barrier in atopic dogs. Barrier dysfunction results in environmental allergens interacting with immune system cells in the skin, triggering inflammation.


… TO YOUR PATIENTS

Key pearls to put into practice:

1

M pachydermatis hypersensitivity is common in dogs with nonfood-induced atopic dermatitis. These dogs experience significant irritation (typically pruritus) from minor quantities of yeast on the body.

2

Testing skin for M pachydermatis via cytologic analysis is important to ensure appropriate treatment. It should not be assumed that every pruritic, erythematous rash is a result of bacterial pyoderma.

3

Topical antimicrobial treatments (eg, shampoos, sprays, mousse products) that contain chlorhexidine combined with climbazole, miconazole, or ketoconazole are an important component of lifelong allergy management. The frequency of application varies based on the formulation, but once or twice weekly is usually ideal.

References

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Digital Edition may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.


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AHS CB June 2022

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Feline Atopic Skin Syndrome

William Oldenhoff, DVM, DACVD, ACCESS Specialty Animal Hospital, San Fernando Valley, California

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Feline Atopic Skin Syndrome

In the Literature

Santoro D, Pucheu-Haston CM, Prost C, Mueller RS, Jackson H. Clinical signs and diagnosis of feline atopic syndrome: detailed guidelines for a correct diagnosis. Vet Dermatol. 2021;32(1):26-e6.


FROM THE PAGE…

The nomenclature surrounding feline allergic dermatitis caused by environmental allergy is complicated. Atopic dermatitis is not generally used, as environmentally allergic cats lack many of the hallmarks of atopic dermatitis seen in dogs and humans. Alternate terminology (eg, nonflea, nonfood-induced hypersensitivity dermatitis) has thus been used, but clearer and more understandable clinical classification is required. Feline atopic syndrome describes all allergic diseases in cats, including flea allergy dermatitis, feline food allergy, feline asthma, and feline atopic skin syndrome; therefore, feline atopic skin syndrome (FASS) is now the preferred term for cats with allergic dermatitis due to environmental allergy. 

This study sought to summarize the current literature on the clinical presentation of FASS and develop diagnostic guidelines. Patients with FASS are typically presented with one or more reaction patterns (ie, miliary dermatitis; self-induced alopecia; face, head, and neck pruritus; eosinophilic granuloma complex). Although mean age of onset varies widely, most reports suggest a young age of onset that ranges from 0.5 to 4.8 years of age.1-7 Female cats1-5,8-10 and Abyssinians6,7 may be overrepresented. There is also evidence of heritability, as is seen in humans and dogs.11-15  

Patients with feline food allergy can be presented with the same reaction patterns as patients with FASS. Other differential diagnoses include ectoparasites, staphylococcal skin infection, and Malassezia spp overgrowth. FASS can be diagnosed when other differential diagnoses, including food allergy, are ruled out. 

Allergen testing should be performed after clinical diagnosis is made and should be used to formulate immunotherapy. Intradermal testing is considered the gold standard but lacks standardization and is generally considered to be more difficult to perform in cats as compared with dogs. Allergen-specific immunoglobulin E serology is widely used but also lacks standardization, and there are reliability concerns.


…TO YOUR PATIENTS

Key pearls to put into practice:

1

Correct diagnosis of FASS requires understanding of typical presentation and methodically ruling out other causes of skin disease, including treating skin infections and ruling out ectoparasites and food allergies.

2

Appropriate use of allergy tests is critical. Intradermal and serum allergy tests do not result in an FASS diagnosis; allergy testing should instead be used as a guide to allergen selection in allergen-specific immunotherapy. Diagnosis is achieved through the clinical process. Allergy testing should only be pursued if the pet owner is committed to immunotherapy, not with the goal of learning which allergens need to be avoided, as allergen avoidance is usually not possible.

3

Immunotherapy is the only treatment that can reverse allergy progression. Therapies to control clinical signs are important to maintain patient comfort but do not stop disease progression. For most allergic patients, allergen-specific immunotherapy is recommended because it is the safest long-term treatment option.

References

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Digital Edition may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.


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When Heartworms Migrate to the Heart in Dogs

Andrew R. Moorhead, DVM, MS, PhD, DACVM (Parasitology), University of Georgia

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When Heartworms Migrate to the Heart in Dogs

In the Literature

Romano AE, Saunders AB, Gordon SG, Wesselowski S. Intracardiac heartworms in dogs: clinical and echocardiographic characteristics in 72 cases (2010-2019). J Vet Intern Med. 2021;35(1):88-97.


FROM THE PAGE …

Intracardiac heartworms in dogs have been associated with caval syndrome. Further exploration is needed to, however, determine the exact percentage of cases that progress to caval syndrome, associated clinical signs, and echocardiographic parameters. Not all dogs with intracardiac heartworms have clinical signs, including hemoglobinuria, which is one of the hallmark signs of caval syndrome.

The aim of this retrospective study was to determine clinical and echocardiographic characteristics of intracardiac heartworm cases. Records from a veterinary teaching hospital from May 2010 to September 2019 were searched to identify dogs that were referred for caval syndrome, underwent heartworm extraction, or showed intracardiac heartworms on echocardiography.

Seventy-two dogs were included in the study and were divided into cases with low worm burden (a few worms; estimated, <5) and high worm burden (more than a few worms and filling the right atrium). A majority of cases (81%) had high worm burden; of these patients, 75% were small-breed dogs. This bias could be due to breed popularity, specifically Chihuahuas, but the authors postulated it could represent a clinically relevant phenomenon. 

Pulmonary hypertension, assessed via echocardiography, was likely in 93% of cases, possibly secondary to vessel blockage, and pigmenturia was detected in 43% of the likely pulmonary hypertension cases. Pigmenturia, anemia, and bilirubinuria were significantly more common in dogs with a high worm burden. Although only 25% of dogs met the criteria for caval syndrome, extraction of worms was performed in 65% of cases. This study emphasizes the importance of echocardiography for identifying intracardiac heartworms and determining worm burden, especially in small-breed dogs. If worm burden is high, regardless of whether the patient has caval syndrome, extraction of worms may be advantageous.


… TO YOUR PATIENTS

Key pearls to put into practice:

1

Echocardiography is key for diagnosing intracardiac heartworms and determining worm burden, especially in small-breed dogs.

2

Dogs with intracardiac heartworms have a high likelihood of pulmonary hypertension, although diagnosis can be confounded by the presence of a large number of worms.

 

3

Presence of intracardiac heartworms does not necessarily indicate caval syndrome; however, the patient may still benefit from extraction of worms.

Suggested Reading

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

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Neurologic Signs in Cats After Portosystemic Shunt Attenuation

W. Alex Fox-Alvarez, DVM, MS, DACVS-SA, University of Florida

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Neurologic Signs in Cats After Portosystemic Shunt Attenuation

In the literature

Strickland R, Tivers MS, Fowkes RC, Lipscomb VJ. Incidence and risk factors for neurological signs after attenuation of a single congenital portosystemic shunt in 50 cats. Vet Surg. 2021;50(2):303-311.


FROM THE PAGE…

The etiology of abnormal neurologic signs following portosystemic shunt (PSS) attenuation surgery in cats and dogs has not been determined. Postattenuation neurologic syndrome (PANS) differs from preoperative hepatic encephalopathy and appears to affect cats more often than dogs. In one study, PANS occurred in 15 out of 25 (60%) cats undergoing surgery for PSS attenuation.1 In contrast, a study found that only 28 out of 253 (11%) dogs developed PANS after surgery2; prophylactic use of levetiracetam as a preventive against PANS was not effective.

This retrospective study of 50 cats treated for PSS aimed to identify risk factors for the development of PANS and report the incidence and patient outcomes. Thirty-one (62%) cats developed PANS; 5 of which did not survive to discharge. Neurologic signs varied in severity and ranged from mild twitching and depression to blindness and generalized seizures. 

The only risk factor identified for the development of PANS in this population was a low serum osmolality at a median 24 hours after surgery. 

No difference was noted in the occurrence of PANS in cats with intra- vs extrahepatic shunts or between cats with or without preoperative hepatic encephalopathy. Patient age and degree of surgical attenuation (partial vs complete) did not affect the incidence of PANS. Prophylactic levetiracetam was not found to decrease the risk for developing PANS in cats.

PANS was the most commonly reported cause of death in this study and is a major concern in cats with PSS. The underlying complexity of this disease may explain the inability to identify multiple risk factors in these cats. Clinicians need to understand and communicate the risks for PANS when counseling cat owners on treatment options for PSS. Although not evaluated directly in cats, surgical treatment of PSS in dogs has been documented to significantly improve quality of life and survival time compared with medical management alone.3


…TO YOUR PATIENTS

Key pearls to put into practice:

1

Signs of PANS can range from mild twitching to refractory generalized seizures.

2

Preoperative hepatic encephalopathy does not appear to be a risk factor for the development of PANS, and prophylactic treatment with levetiracetam did not decrease the risk for PANS in cats.

3

To facilitate an informed decision, owners should be counseled on the risks and potential benefits of medical and surgical management of PSS in cats.

References

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Digital Edition may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.


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Communication Challenges Between Breeders & Clinicians

Carla Barstow, DVM, MS, DACT, Highland Pet Hospital, Lakeland, Florida

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Communication Challenges Between Breeders & Clinicians

In the Literature

Englar RE, Schettler KA, Ostrom SA. Survey of communication challenges that impact relationships between veterinarians and dog or cat breeders and proposed solutions for retaining breeders as clients. J Am Vet Med Assoc. 2021;258(4):407-415.


FROM THE PAGE…

Good communication skills are vital in the clinic. Ineffective communication can result in failure and frustration that leads to resentment. Negative experiences can influence future interactions, possibly preventing adequate communication. 

This social media-based survey included 793 dog breeders, 540 cat breeders, and 514 clinicians and aimed to characterize communication challenges between breeders and clinicians. The survey also sought to identify areas in which communication and relationships may be improved. 

Key issues identified by breeders included clinicians having apparent lack of veterinary training in theriogenology, not acknowledging breeder knowledge or experience, expressing disapproval of breeding, and making assumptions about breeder character or motivation. Clinicians described issues such as breeder disrespect, financial constraints, lack of prioritization of patient health, unethical behaviors, and trust of anecdotal reporting rather than evidence-based medicine. Potential solutions include effective communication and increased education. 

These survey results highlight the importance of good communication. Common myths and assumptions often lead to ineffective communication, emphasizing the importance of a relationship based on mutual trust and respect.


…TO YOUR PATIENTS

Key pearls to put into practice:

1

Active listening that includes being fully engaged in conversation (not thinking ahead about the response) and not jumping to conclusions can be helpful. Closed and/or negative body language should be avoided.

2

Assumptions and negative past experiences should not distract from or guide the conversation. For example, not all breeders are unethical, and not all clinicians care more about money than the patient.

3

Clinician collaboration with dog and cat breeders is needed, as they typically have extensive experience regarding the breed. Breeders should be considered part of the healthcare team that is working toward a potential common goal of healthier dogs and cats.

References

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Digital Edition may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.


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Research Note: Comparison of Anal Purse-String Suture Techniques

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Anal purse-string suture can decrease the risk for fecal contamination and subsequent surgical site infection during surgery in the perianal region and in some pelvic limb orthopedic procedures. This study aimed to identify which anal purse-string suture technique (ie, 3 bites with 0.5 cm between bites, 5 bites with 0.5 cm between bites, 3 bites with 1 cm between bites) required the fewest tissue bites to create a consistent leak-proof closure. All techniques used 2-0 monofilament nylon suture placed in the cutaneous tissue surrounding the anus and knotted with 6 square throws. Leak pressure testing demonstrated resistance to leakage regardless of technique, but 3 bites with 0.5 cm between bites was recommended, as it provided the highest resistance to leakage and used the fewest bites.

Source

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Digital Edition may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.


Non-Core Vaccination Rates: Where Does the Data Drive Us?

Non-Core Vaccination Rates: Where Does the Data Drive Us?

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Non-Core Vaccination Rates: Where Does the Data Drive Us?
Sponsored by Elanco

Key Takeaways

  • A recent study was the first of its kind to evaluate the variability of non-core vaccination rates across the United States.
  • Substantial variability in non-core vaccination rates was identified between adjacent states as well as practices within the same state.
  • Study results provide evidence that factors other than disease risk influence non-core vaccination rates.
  • Clinics should review protocols and use combination vaccines to increase compliance and close gaps in protection.

Vaccination is a safe, affordable, and reliable means for preventing infectious diseases in dogs and cats1-3; however, rabies is the only vaccine required by law in most states. Administration of other vaccines is left up to practitioner discretion, along with the owner’s decision based on patient risk assessment.1,2 Vaccines that are not required (eg, Leptospira, Borrelia burgdorferi, Bordetella bronchiseptica, feline leukemia virus [FeLV]) are termed “non-core” or “lifestyle” vaccines, as this term conveys that a pet’s individual risk and lifestyle should be factors when decisions surrounding vaccination are made.

When considering vaccinations, components such as geographic location, patient lifestyle, and other risk factors may actually make a lifestyle vaccine core for a particular animal. However, appropriate risk assessment presents challenges, requiring careful questioning, accurate disease prevalence information, and factual owner responses.

Inaccurate risk assessment leaves dogs and cats unprotected from preventable infectious diseases, including leptospirosis, Lyme disease, bordetellosis, and FeLV. This difficulty is compounded by several factors, including limited expert guidelines on many vaccines. Such is the case with Bordetella bronchiseptica, for which guidelines may be conflicting or unclear, and with leptospirosis, which may be considered core in many areas across the United States but still termed a lifestyle vaccine.2,5 In addition, there is disagreement amongst experts in the Lyme borreliosis consensus statement, in which opinions were evenly split on vaccination and no consensus was reached.6 With such limitations, an improved understanding of how and where lifestyle vaccines are being used across the country, as well as geographic vaccination rates and variability across nearby clinics, could help ensure practitioners make decisions to best protect their patients.

THE STUDY


Malter KB, Tugel ME, Gil-Rodriguez M, et al. Variability in non-core vaccination rates of dogs and cats in veterinary clinics across the United States. Vaccine. 2022;40(7):1001-1009.


A recent study was the first of its kind to evaluate vaccination rates for several lifestyle vaccines in dogs and cats that were current on core vaccines (dogs: distemper, adenovirus, parvovirus [DAP]; cats: feline viral rhinotracheitis, calicivirus, and panleukopenia virus [FVRCP]).4 The study utilized data obtained between November 1, 2016, and January 1, 2020. Patients were included only if they were current for core vaccines as recommended by AAHA2 and at least 6 months of age. Thus, the study’s authors selected the most compliant clients at each practice, implying the data is likely a best case scenario or overestimation for lifestyle vaccination rates across the country. Patients current on core vaccines, adjusted for whether clinics followed 1-year or 3-year protocols and with a 2-month grace period, were divided into those current on lifestyle vaccines.

The Results

The records of 5.5 million dogs in 1,670 clinics and 1.9 million cats in 1,661 clinics in 48 states were screened for inclusion. Just <2.8 million dogs and 790,000 cats were considered fully compliant with core vaccines; their lifestyle vaccine status was analyzed, with respect to Leptospira, B burgdorferi, B bronchispetica, canine influenza virus, and FeLV vaccines (Table).

MEDIAN VACCINATION RATES FOR NON-CORE VACCINES

Canine Non-Core Vaccine Median Vaccination Rate at All Study Clinics
Leptospira 70.5%
B burgdorferi 51.8%
B bronchiseptica 68.7%
Feline Non-Core Vaccine Median Vaccination Rate at All Study Clinics
FeLV 34.6%

 

Leptospirosis

Nationally, 63.4% of core compliant dogs in the study received leptospirosis vaccines, with a median clinic rate of 70.5%. Vaccination rates were higher in the midwest and south-central states. There was high variability within clinics in the same geographic region; some clinics had very high or even 100% leptospirosis vaccination rates, suggesting that the disease is approached as core amongst those practitioners and likely a geographic risk to dogs in those areas, whereas neighboring clinics had a 0% vaccination rate.

Borreliosis

In 11 states identified as Lyme-endemic by the CDC, 47.9% of core compliant dogs in the study were vaccinated against Lyme disease, with a median clinic vaccination rate of 51.8%. Of those states, the lowest vaccination rate was Virginia (18.2%). As with leptospirosis, there was high variability amongst clinics in the same geographic area, with 1 clinic having a vaccination rate exceeding 90% and a neighboring clinic at 0%. Additional data available to assess perceived borreliosis risk for Lyme-endemic region dogs included information on the purchase of tick prevention at the clinic in the last year. The purchase of tick prevention suggests that the dog has been determined to be at risk for tick exposure.

Year-round tick prevention and annual vaccination are recommended for dogs at risk for Lyme borreliosis in endemic regions.7 In this study, tick prevention was purchased in clinic by >40% of owners of dogs that were core compliant but not vaccinated against Lyme borreliosis and living in a Lyme-endemic state. This marks a disconnect between perceived risk (recommendation of tick prevention) and recommended disease prevention strategies for year-round tick prevention and vaccination in some clinics in those endemic areas.

Bordetella bronchiseptica

Nationally, 64.6% of core compliant dogs in the study received B bronchiseptica vaccines, with a median clinic rate of 68.7%. The south-central and southeast regions had higher rates geographically, and the northeast had the lowest vaccination rate. There was wide vaccination rate variability within states, ranging from 0% to almost 100% in similar geographic regions.

Feline Leukemia

Nationally, 32.8% of core compliant adult cats were vaccinated against FeLV, with a median clinic rate of 34.6%. FeLV vaccination is considered to be core for all cats <1 year of age, as this age group is most susceptible to infection.2 For cats for which the vaccine was considered core (ie, cats <1 year of age), national and median clinic rates were similar at 36.8%. Of kittens and 1-year-old cats, 63.2% were not vaccinated for FeLV, despite expert guidelines classification as a core vaccination.2

Discussion

This study was the first to evaluate lifestyle vaccination rates in a large number of dogs and cats to help practitioners make risk-assessment decisions. Given that the sampled dogs and cats represented the most compliant clients at their respective practices, there is likely a substantially larger population that is unprotected from those diseases in each state. Less compliant or noncompliant patients represent an opportunity for further evaluation, owner education, practice growth, and preventive healthcare.

Given that the sampled dogs and cats represented the most compliant clients at their respective practices, there is likely a substantially larger population that is unprotected from those diseases in each state.

In this study, the differences in vaccination rates among states are understandable for diseases with a defined geographic risk. However, of current lifestyle vaccines for dogs and cats, only Lyme borreliosis has defined endemic states, and consideration should be given to the fact that Lyme borreliosis in humans is spreading geographically.8 This study also did not assess risks to pets associated with traveling among states, which is increasingly common and a way in which a pet outside an endemic state may encounter risk for exposure to Lyme borreliosis.

FeLV, leptospirosis, and B bronchiseptica are not strictly geographically limited with endemic and non-endemic regions; thus, the variability between states represents an opportunity for growth in risk assessment and protection of dogs and cats.9,10 However, the data also show that, to some degree, risk assessment is indeed at play for some of these vaccine recommendations. Of dogs vaccinated for Lyme borreliosis, 85.5% also received leptospirosis vaccines, showing an understanding of the overlap in risk factors between the 2 diseases. Dogs assessed to be at risk for exposure to Ixodes spp ticks carrying B burgdorferi are also at risk for both direct or indirect exposure to leptospirosis reservoirs (eg, rats, mice, voles, skunks, raccoons); therefore, dogs that receive Lyme vaccines should also be protected from leptospirosis by vaccination.

There was also a high degree of variability within states between practices for each disease studied, which suggests that factors other than disease risk are influencing those lifestyle vaccine rates. Using leptospirosis as a well-documented example, recent work has shown that urban and small-breed dogs are also at risk for leptospirosis.11,12 Thus, the variability in protection within states may be due to the difficulty of risk assessment, lack of awareness of expert guidelines or regional disease risk, the strength of the veterinary recommendation, and/or pet owner adherence to recommendations for any number of reasons, including vaccine hesitancy.13 Ultimately, there is likely a substantial gap in lifestyle vaccine compliance with unprotected dogs and cats at risk for preventable diseases across the United States.

There is likely a substantial gap in lifestyle vaccine compliance with unprotected dogs and cats at risk for preventable diseases across the United States.

Limitations of the study include that practice records cannot account for vaccines not received at that clinic, as clients may utilize multiple clinics or low-cost vaccine clinics, may provide limited information about individual patient risk factors, and/or may not note when vaccines were offered but declined and for what reasons. Better knowledge of when and why pet owners agree to some vaccines but decline others is needed to address vaccine hesitancy in pet owners and ensure best protection for dogs and cats from preventable diseases.13

Implications for Practice

The study indicates that substantial variability exists in lifestyle vaccination rates, and these inconsistencies leave dogs and cats at risk for vaccine-preventable diseases.

For the first time, data are available to evaluate lifestyle vaccine compliance in a large group of core compliant dogs and cats. Although this is an exceptionally large cohort for a study in veterinary medicine, the numbers become much more narrow when limiting inclusion to core compliant dogs and cats. Dogs included dropped from 5.5 million to 2.8 million, meaning almost half of the clinics’ dogs were not core compliant. Cats included decreased from 1.9 million to 790,000, demonstrating that almost 60% of clinics’ cats were not core compliant at the time of evaluation.

Ensuring that dogs and cats receive appropriate lifestyle vaccines ultimately hinges upon accurate risk assessment. It is important for clinics to have a consistent, well-understood protocol for risk assessment. These data should help practitioners better understand where and how vaccines for leptospirosis, Lyme borreliosis, B bronchiseptica, and FeLV are being used in their geographic region and empower them to make stronger recommendations or consider moving some vaccines such as leptospirosis to core in alignment with expert guidelines.5 Practices may choose to expand protection for their patients without sacrificing client experiences and aligning with Fear Free® practices by using multivalent vaccines, including core and lifestyle vaccines such as low-volume FVRCP with FeLV or Lyme and leptospirosis combination vaccines in clinics using a 3-year DAP protocol. Properly identifying dogs and cats at risk for diseases such as leptospirosis, Lyme borreliosis, B bronchiseptica, and FeLV and creating individualized vaccination plans will ensure more dogs and cats are maximally protected against preventable, costly, and potentially fatal diseases.


EXPERT COMMENTARY

As veterinarians, few things are as frustrating as seeing our patients suffer from vaccine-preventable diseases. For vaccines considered core, the choice to vaccinate is easy, but for vaccines considered non-core or lifestyle, the choice can be less clear. For those diseases, we are charged with accurately assessing risk to each pet to create individualized vaccine plans. Some diseases for which vaccines are considered lifestyle (eg, leptospirosis, FeLV) can be deadly, and expert guidelines recommend they be considered core in some animals. This large-scale study was the first of its kind to report lifestyle vaccine rates amongst core vaccine-compliant dogs and cats across 48 US states. This study showed a wide range in vaccination rates within states and among states for diseases for which minimal geographic differences in risk exist. Importantly, it also showed that clinicians recognize the overlap in risk factors between dogs at risk for Lyme and leptospirosis, as most dogs vaccinated for Lyme borreliosis also received leptospirosis vaccines. The results of this study will hopefully empower clinicians to more strongly advocate for the use of appropriate lifestyle vaccines in their practice, moving some such as leptospirosis to core when appropriate.—Jessica Pritchard, VMD, MS, DACVIM (SAIM)


References

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Digital Edition may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.


Continuous Glucose Monitoring in Cats

Matthew Kornya, DVM, ABVP (Feline) Residency Trained, ACVIM (SAIM) Resident, Ontario Veterinary College, The Cat Clinic, Ontario, Canada

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Continuous Glucose Monitoring in Cats

In the Literature

Del Baldo F, Fracassi F, Pires J, et al. Accuracy of a flash glucose monitoring system in cats and determination of the time lag between blood glucose and interstitial glucose concentrations. J Vet Intern Med. 2021;35(3):1279-1287.


FROM THE PAGE …

Continuous interstitial glucose monitoring systems have recently become available in veterinary medicine. These small, portable devices can be easily applied and allow continuous measurement of interstitial fluid glucose,1 providing frequent readings with minimal pet owner and patient stress.2 Clinical applications for interstitial glucose have been reported in several veterinary species,3,4 but direct comparisons to blood glucose in cats are lacking, and reports on tolerability and application are largely anecdotal.

In the first part of this study, 20 pet diabetic cats receiving insulin had their blood glucose measured with a glucometer; results were compared with interstitial glucose readings. All cats had been treated with insulin glargine (median dose, 2 units) for at least one month prior to sensor application. Frequency of administration was not recorded. One cat had concurrent acromegaly; no other cats had comorbidities.

Sensor application was generally straightforward; 19 out of 20 applications were successful. Sensors were well tolerated in 17 cats, whereas 3 cats removed the sensors within 48 hours. The median wearing period was 5.5 days, with no significant difference for sensors secured with additional tissue glue. One cat had a local erythematous reaction thought to be caused by the device adhesive and additional tissue glue.

Strong positive correlation was present between interstitial glucose and blood glucose; however, only 47% of interstitial glucose readings <100 mg/dL, and 43.6% of readings >100 mg/dL, were within 15 mg/dL of blood glucose. Thus, the interstitial glucose monitor did not meet International Organization for Standardization criteria. The interstitial glucose monitoring system often underestimated blood glucose, particularly in cats in the hyperglycemic range. 

The second part of the study evaluated correlation between interstitial glucose and blood glucose in 7 healthy, purpose-bred cats undergoing IV glucose tolerance testing. Interstitial glucose increased more slowly than blood glucose measured via glucometer in these cats when a rapid dextrose infusion was administered; no positive correlation was noted. When the infusion was slow, a strong positive correlation was seen, and interstitial glucose consistently underestimated blood glucose. 

This study was well designed but had some limitations. Pet diabetic cats were stable and otherwise healthy, but this may not represent the population of diabetic cats with dehydration or other comorbidities that can affect interstitial glucose readings.3 In addition, IV glucose tolerance tests were performed in healthy, purpose-bred cats; this may not replicate clinical situations of rapid glucose change. 

Recent data have been published regarding successful use of interstitial monitors in dogs4,5 and cats3 with diabetic ketoacidosis, suggesting that the slower increase of interstitial glucose compared with blood glucose during periods of rapid change may not be clinically relevant. 

The authors concluded that, although interstitial glucose monitors did not fulfill International Organization for Standardization requirements, they are sufficiently accurate for glucose monitoring in diabetic cats and are clinically useful. Further study is needed, particularly on how to keep the sensor on the cat for longevity.


… TO YOUR PATIENTS

Key pearls to put into practice:

1

Interstitial glucose monitors are expected to fail earlier in cats than in dogs or humans.

2

It is important to be aware of the lag in interstitial glucose management in situations of rapid glucose change.

 

3

Interstitial glucose results are less accurate at very high glucose concentrations.

References

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Digital Edition may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.


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Risk Factors for Enterococcal Bacteriuria in Dogs

Shelly J. Olin, DVM, DACVIM (SAIM), University of Tennessee

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Risk Factors for Enterococcal Bacteriuria in Dogs

In the literature

Wood MW, Lepold A, Tesfamichael D, Lasarev MR. Risk factors for enterococcal bacteriuria in dogs: a retrospective study. J Vet Intern Med. 2020;34(6):2447-2453.


FROM THE PAGE …

Enterococcus spp are commensals of the GI tract in dogs. These bacteria are generally considered to have low virulence, but they can be pathogenic and colonize in the bile, blood, and urine in dogs.1-4 An established infection can be difficult to eradicate because Enterococcus spp rapidly acquire multidrug antimicrobial resistance.5 

This study sought to identify risk factors that predispose dogs to enterococcal bacteriuria. Records of 70 dogs with Enterococcus spp bacteriuria were reviewed and compared with those of 70 dogs with Escherichia coli bacteriuria to observe clinical and pathologic variables. Similar to other studies, Enterococcus faecalis was the predominant species identified in 61% of cases.1,6 This species is noteworthy and relevant to clinical practice because it contains more virulence genes and expresses higher levels of antimicrobial resistance as compared with other species.7,8

Of those dogs with Enterococcus spp infection, 60.6% had a history of recurrent bacteriuria, which was more common than in dogs with E coli bacteriuria. Lower urinary tract (LUT) anatomic abnormalities, uroliths, and the presence of LUT neoplasia were also more common in dogs with Enterococcus spp bacteriuria. 

Studies in mice9,10 and humans11,12 suggest that local inflammation and proteinuria, specifically fibrinogen and inflammatory mediators (ie, interleukin 6, interleukin 1β), can cause predisposition to colonization with Enterococcus spp. The current study was not designed to assess this predisposition in dogs, but an association with previous infection or urinary tract injury in dogs with enterococcal infection was noted.

Limitations of this study included a low number of dogs with certain comorbidities that compromised the ability to calculate an odds ratio (ie, strength of association between events) for these variables, as well as incomplete medical records for some dogs. It is possible that enterococcal UTI has risk factors not evaluated in this study.


…TO YOUR PATIENTS

Key pearls to put into practice:

1

Risk factors for Enterococcus spp bacteriuria in dogs include a history of recurrent bacteriuria, LUT abnormalities, uroliths, and LUT neoplasia.

 

2

Enterococcus spp generally have low virulence, but they can colonize in the bile, blood, and urine of dogs. Eradication can be difficult once an enterococcal infection is established, and these bacteria can rapidly acquire antimicrobial resistance.

3

In this study, ≈55% of dogs infected with Enterococcus spp in the urinary tract were presented with LUT signs (eg, stranguria, pollakiuria, dysuria, gross hematuria); thus, up to 45% of cases may have been subclinical.

4

Enterococcus spp bacteriuria could serve as a marker of underlying LUT inflammation if LUT inflammation promotes colonization with these bacteria in dogs, similar to what is seen in humans.

References

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Digital Edition may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.


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Claro CB June 2022

Current Understanding of Golden Retriever Pigmentary Uveitis

Elizabeth A. Giuliano, DVM, MS, DACVO, University of Missouri

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Current Understanding of Golden Retriever Pigmentary Uveitis

In the Literature

Jost HE, Townsend WM, Moore GE, Liang S. Golden retriever pigmentary uveitis: vision loss, risk factors for glaucoma, and effect of treatment on disease progression. Vet Ophthalmol. 2020;23(6):1001-1008.


FROM THE PAGE…

Golden retriever pigmentary uveitis (GRPU) has unique ocular features, and because of its relatively high prevalence (10%-18%) in older golden retrievers, it is suspected to be an inheritable trait in this breed.1,2 The hallmark clinical features include pigment deposition on the anterior aspect of the lens capsule (often in a radial pattern), fibrinous type material in the anterior chamber, posterior synechia, pigment on the corneal endothelium and iris, and uveal cysts. GRPU typically affects both eyes and results in vision loss in ≈50% of affected eyes within a year of initial diagnosis (Figure).3

In this study, serial examinations were performed on 29 golden retrievers (58 eyes) with pigmentary uveitis to determine the proportion of dogs with GRPU that developed vision loss, risk factors for development of glaucoma, and effect of treatment on disease progression. Dogs had to have a diagnosis of GRPU—defined by the presence of radial pigment on the anterior lens capsule—in at least one eye and a minimum 6-month lapse between examinations to be included in the study.

Vision loss in 7 of 9 (77.8%) eyes was secondary to glaucoma, and posterior synechiae and fibrinous material in the anterior chamber were significant risk factors for glaucoma. There was no significant difference in disease progression in patients treated with topical steroids or NSAIDs. The authors concluded that GRPU is a slowly progressive disease with a guarded long-term prognosis for vision and patient comfort.

An 8-year-old, spayed golden retriever with end-stage GRPU in the right eye; pain was present and there was no vision in this eye. Episcleral hyperemia, moderate diffuse corneal edema due to secondary glaucoma (intraocular pressure, 45 mm Hg), posterior synechia, and early cataract development can be seen.
An 8-year-old, spayed golden retriever with end-stage GRPU in the right eye; pain was present and there was no vision in this eye. Episcleral hyperemia, moderate diffuse corneal edema due to secondary glaucoma (intraocular pressure, 45 mm Hg), posterior synechia, and early cataract development can be seen.

FIGURE An 8-year-old, spayed golden retriever with end-stage GRPU in the right eye; pain was present and there was no vision in this eye. Episcleral hyperemia, moderate diffuse corneal edema due to secondary glaucoma (intraocular pressure, 45 mm Hg), posterior synechia, and early cataract development can be seen.

FIGURE An 8-year-old, spayed golden retriever with end-stage GRPU in the right eye; pain was present and there was no vision in this eye. Episcleral hyperemia, moderate diffuse corneal edema due to secondary glaucoma (intraocular pressure, 45 mm Hg), posterior synechia, and early cataract development can be seen.


…TO YOUR PATIENTS

Key pearls to put into practice:

1

GRPU can be devastating in golden retrievers because it can result in vision loss of ≈50% of affected eyes within a year of initial diagnosis and is likely heritable. It is recommended that owners/breeders of golden retrievers establish a good working relationship with a board-certified veterinary ophthalmologist to help manage the course of disease and receive appropriate breeding advice.

2

The presence of uveal cysts alone is not pathognomonic for GRPU and thus should not be overinterpreted.

3

Although this study found no evidence that a topical anti-inflammatory drop slows the course of GRPU, the number of study participants was small. However, many ophthalmologists use these drugs in GRPU patients. Regular follow-up examination (eg, every 4-6 months) with applanation or rebound tonometry is critical for appropriate administration of antiglaucoma medication to help preserve patient vision and ocular comfort for as long as possible.

References

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Digital Edition may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.


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Selarid CB June 2022

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ACVO/Epicur CB June 2022

Research Note: Vertebral Heart Size & Vertebral Left Atrial Size in Maltese Dogs

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Vertebral heart size (VHS) and vertebral left atrial size (VLAS) are common radiographic measurements for assessing cardiac enlargement in dogs. Reference intervals vary among breeds and have not been previously published for Maltese, which are predisposed to cardiac enlargement. This retrospective study described reference intervals for VHS and VLAS in 81 healthy Maltese. Mean VHS (9.5 ± 0.46 vertebrae) and median VLAS (2 ± 1.8-2.1 vertebrae) were lower than previously reported standard threshold values. Measurements were not influenced by sex, age, or weight, and intra- and interobserver agreement was high.

Source

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Digital Edition may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.


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easOtic CB June 2022

Research Note: Whole Lung Irradiation for Appendicular Osteosarcoma in Dogs

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Despite successful local tumor control, ≈90% of dogs with appendicular osteosarcoma develop metastasis, and pulmonary metastasis is the most common cause of death. Chemotherapy for treatment of metastases has been largely unsuccessful in these patients and is associated with increased toxicity. This study evaluated the feasibility and safety of whole lung irradiation (WLI), an adjuvant technique used in human osteosarcoma patients, to treat dogs with appendicular osteosarcoma. Included in the study were 12 dogs that underwent successful amputation, received 4 doses of carboplatin, and did not have evidence of gross metastasis. 

Radiation was delivered via a linear accelerator; 10 daily fractions of 1.75 Gy were administered to each dog for a total of 17.5 Gy. WLI was well tolerated in all dogs. No dogs demonstrated signs of radiation toxicity. The median disease-free interval (376 days) was not significantly longer than in the control group (304.5 days); however, the authors noted WLI may be beneficial in some patients. Larger studies that include adjustments in timing of WLI should be considered.

Source

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Digital Edition may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.


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Metacam CB June 2022

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KBroVet CB June 2022

Incisional Wedge Biopsy of Subcutaneous Tumors

Lisa Corti, DVM, DACVS, CCRP, North Shore Veterinary Surgery, Andover, Massachusetts, North Shore Community College, Danvers, Massachusetts

Oncology

|
Peer Reviewed

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Incisional Wedge Biopsy of Subcutaneous Tumors

Tumor histopathology can determine tissue type, presence of neoplastic or inflammatory processes, cell behavior or tumor grade, appropriate staging diagnostics, treatment options, and prognosis.1 Knowledge of tissue type can also help pet owners make informed decisions.

Subcutaneous tissue tumors are common.2,3 Fine-needle aspiration can accurately differentiate neoplastic from inflammatory processes and is often the first test performed4; however, not all cytologic samples are diagnostic or accurate, especially when peripheral inflammation or necrotic centers of tumors are sampled.4,5 Surgical biopsy is therefore often pursued as it can provide tissue that reveals the underlying architecture and interplay of cells.1 Tumor grade can only be identified via biopsy.1,2,6,7

Types of Surgical Biopsy

Surgical biopsies are excisional or incisional. Excisional biopsy involves removal of an entire mass without prior knowledge of tumor type7; surgical margins may be inadequate, risking tumor regrowth, and additional aggressive surgery or adjuvant treatment (eg, radiation, chemotherapy) may be needed.7 Incisional biopsy involves excision and submission of a small piece of the tumor; this indicates the tumor type before definitive removal, and appropriate surgical margins can be planned.7

Incisional biopsies can be performed using a punch biopsy instrument, specialized biopsy needle device, or wedge technique.1,2,7 Punch biopsies of the outer layers of a subcutaneous tumor are less likely to be diagnostic because the depth of the circular blade determines the depth of the sample.7 Although needle biopsies have a high rate of diagnostic accuracy, specialized cutting needles are required and advanced imaging modalities may be needed to increase the accuracy of sample retrieval.1,2,6,7 Wedge biopsy can provide direct visualization of abnormal tissue, control of the length and depth of the sample, and avoidance of specialized equipment use.1,7

Anesthesia is not always needed for wedge biopsies; heavy sedation, analgesics, and a local anesthetic are often sufficient.

Large left ischial and proximal thigh mass in a dog with ulceration and tumor rupture through the skin. This ulcerated area should be avoided during wedge biopsy.
Large left ischial and proximal thigh mass in a dog with ulceration and tumor rupture through the skin. This ulcerated area should be avoided during wedge biopsy.

FIGURE 1 Large left ischial and proximal thigh mass in a dog with ulceration and tumor rupture through the skin. This ulcerated area should be avoided during wedge biopsy.

FIGURE 1 Large left ischial and proximal thigh mass in a dog with ulceration and tumor rupture through the skin. This ulcerated area should be avoided during wedge biopsy.

Biopsy Location

Sample location is an important consideration for wedge biopsy of a subcutaneous tumor. Sampling from the junction of a lesion and normal tissue is commonly recommended for dermatologic biopsies3,7; however, sampling a subcutaneous mass at this junction can lead to inadvertent spread of cancer cells beyond the original tumor.1,7 Removal of the original biopsy site should be considered if definitive tumor excision is performed later, as the biopsy site is considered contaminated with tumor cells. Sampling closer to the center of the mass may be preferable, but areas of inflammation or necrotic debris should be avoided (Figure 1). 

Understanding the appearance of healthy tissue and normal tissue layering is key to distinguishing neoplastic from normal tissue. Familiarity with regional anatomy overlying and adjacent to a subcutaneous mass can help avoid inadvertent damage to vital structures (eg, blood vessels, nerves; Figure 2). Many tumors have a capsule or pseudocapsule, which should be grossly differentiated from normal tissue layers and penetrated during dissection to obtain a sample of the underlying tumor.2,7

Narrow and deep wedge biopsies are most likely to obtain an accurate sample.7 Because the wedge biopsy site is considered contaminated, and a lengthy incision that may contain cancer cells can make definitive removal with adequate margins challenging, the skin incision should not span the entire width of the tumor. Depending on the size of the mass, the incision can vary from a few millimeters to a few centimeters.

Small subcutaneous mass over the distal radius and carpus in a dog. Awareness of the cephalic and accessory cephalic vein (A; solid arrow) locations can help avoid inadvertent laceration of these vessels. Incision was made through the subcutaneous tissue lateral to the vessel (B; dashed arrow).&nbsp;
Small subcutaneous mass over the distal radius and carpus in a dog. Awareness of the cephalic and accessory cephalic vein (A; solid arrow) locations can help avoid inadvertent laceration of these vessels. Incision was made through the subcutaneous tissue lateral to the vessel (B; dashed arrow).&nbsp;

FIGURE 2 Small subcutaneous mass over the distal radius and carpus in a dog. Awareness of the cephalic and accessory cephalic vein (A; solid arrow) locations can help avoid inadvertent laceration of these vessels. Incision was made through the subcutaneous tissue lateral to the vessel (B; dashed arrow). 

Small subcutaneous mass over the distal radius and carpus in a dog. Awareness of the cephalic and accessory cephalic vein (A; solid arrow) locations can help avoid inadvertent laceration of these vessels. Incision was made through the subcutaneous tissue lateral to the vessel (B; dashed arrow).&nbsp;
Small subcutaneous mass over the distal radius and carpus in a dog. Awareness of the cephalic and accessory cephalic vein (A; solid arrow) locations can help avoid inadvertent laceration of these vessels. Incision was made through the subcutaneous tissue lateral to the vessel (B; dashed arrow).&nbsp;

FIGURE 2 Small subcutaneous mass over the distal radius and carpus in a dog. Awareness of the cephalic and accessory cephalic vein (A; solid arrow) locations can help avoid inadvertent laceration of these vessels. Incision was made through the subcutaneous tissue lateral to the vessel (B; dashed arrow). 

FIGURE 2 Small subcutaneous mass over the distal radius and carpus in a dog. Awareness of the cephalic and accessory cephalic vein (A; solid arrow) locations can help avoid inadvertent laceration of these vessels. Incision was made through the subcutaneous tissue lateral to the vessel (B; dashed arrow). 

Sample Submission

The pathology form should be filled out completely when a biopsy sample is submitted so the pathologist can provide an informed, accurate, and clinically relevant diagnosis (see Pathology Form).8 A study found >88% of biopsy submission forms supplied inadequate clinical information in at least one key content area, and 3% of forms were devoid of information beyond signalment.9 Inadequate information significantly influenced reporting of clinical information by the pathologist.9

PATHOLOGY FORM8

A pathology form should include:

  • Signalment
  • Diagnostic information and pertinent results from blood work, hormonal tests, radiography, ultrasonography, and advanced imaging (eg, MRI, CT)
  • Tumor site (specific), duration, and rate of growth
  • Gross description of the tumor, including size, shape, character, associated tissue layer, vascularity, and ulceration  
  • Tumor-associated clinical signs (eg, lameness, pruritus, skin changes)
  • Type of biopsy (eg, incisional, excisional) and method used (eg, punch, needle, wedge)
  • Previous tumor treatments 
  • Results of previous tumor-related tests (eg, cytology, biopsies) and diagnostics (eg, radiography, ultrasonography, CT)

STEP-BY-STEP

INCISIONAL WEDGE BIOPSY


WHAT YOU WILL NEED

  • Clippers
  • Sterile surgical scrub and alcohol
  • Sterile gown and gloves
  • Sterile instrument pack
    • Scalpel blade handle
    • Brown-Adson thumb forceps
    • Needle holders
    • Suture scissors
  • #10 or #15 scalpel blade
  • Small biopsy jar with 10% buffered formalin
  • 3-0 synthetic absorbable monofilament suture (eg, poliglecaprone, polydioxanone)
  • 3-0 synthetic nonabsorbable monofilament suture (eg, nylon)
  • Histopathology form

STEP 1

Clip and aseptically prepare the mass and surrounding skin.


STEP 2

Apply sterile drapes around the tumor or biopsy site.

Author Insight

Ulcerated areas should be draped out of the field of view when possible.


STEP 3

Incise through the skin (A) and underlying subcutaneous tissue (B) over the mass.

Clinician's Brief
Clinician's Brief

Author Insight

Length of the incision should not span the entire mass.


STEP 4

Identify and incise the tumor capsule (A, arrow; subcutaneous lipoma) or pseudocapsule (B, dashed arrow; subcutaneous sarcoma).2,7

Clinician's Brief
Clinician's Brief

Author Insight

A true tumor capsule and a tumor pseudocapsule are distinguished histologically; grossly, they appear similar. The tumor capsule is usually found deep to the subcutaneous fat and can be separated from the adipose layer for better identification. Dissection of highly vascular, friable, or amorphous tumors may not be possible.


STEP 5

Incise the tumor, slicing down and inward as if following the side of an inverted triangle (A). Remove the scalpel blade and angle it in the opposite direction, slicing down and inward on the other side of the imaginary inverted triangle (B).

Clinician's Brief
Clinician's Brief

Author Insight

Depth of the inverted triangle should be greater than the width of its base.7 A nondiagnostic biopsy result is commonly caused by sampling only the superficial tissues surrounding a mass. It is important to cut into the tumor. When uncertain on how deep to make the wedge, it is better to cut deeper.


STEP 6

Continue incising into the tumor until the point of the inverted triangle is reached and the wedge is released. Place the specimen in 10% neutral buffered formalin immediately after excision to limit tissue artifacts.8

Author Insight

The ratio of tissue to 10% neutral buffered formalin should be 1:10.8

Tumor sample shown here has 2 distinct regions (solid arrow, circular and homogeneous; dashed arrow, layered and heterogeneous). Gross and microscopic variations in the same sample can help provide a more accurate histopathologic diagnosis.8


STEP 7

Close the subcutaneous and subcuticular layers and the skin layers routinely.

Author Insight

Hemorrhage is often a concern, and certain tumor types (eg, hemangiosarcoma, highly vascular soft tissue sarcomas) can bleed considerably. This should not deter incising deeply into the tumor. Hemorrhage can be controlled by closing the biopsy site with a cruciate or horizontal mattress suture pattern across the junction of normal and abnormal tissue. Direct digital pressure or hemostatic powder and foam can be used if the tissue is friable. If a blood vessel is inadvertently lacerated, it can be clamped with a mosquito hemostat and ligated or cauterized. Applying ice to the incision during recovery and at home can help limit bleeding and hematoma formation.

References

For global readers, a calculator to convert laboratory values, dosages, and other measurements to SI units can be found here.

All Clinician's Brief content is reviewed for accuracy at the time of publication. Previously published content may not reflect recent developments in research and practice.

Material from Digital Edition may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.


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Revolution CB June 2022

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HeartGard/NexGard CB June 2022
Canine Allergic & Atopic Dermatitis: An Updated Understanding & New Approach to Management

Canine Allergic & Atopic Dermatitis: An Updated Understanding & New Approach to Management

Dermatology

|
Sponsored

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Canine Allergic & Atopic Dermatitis: An Updated Understanding & New Approach to Management
Brought to you by Zoetis

Expert views from the Zoetis Petcare Dermatology Advisory Board Proceedings

Meet the Experts
  • Ashley Bourgeois, DVM, DACVD, Veterinary Dermatologist & Owner, Animal Dermatology Clinic Portland
  • Jeanne Budgin, DVM, DACVD, Veterinary Dermatologist & Founder, Hudson Valley Veterinary Dermatology
  • Michael Canfield, DVM, DACVD, Veterinary Dermatologist & Owner, Animal Dermatology South New Port
  • Jay Crisman, DVM, Veterinarian & Owner, 280 Animal Medical Center 
  • Nell Dalton, DVM, Emergency Veterinarian, WestVet 
  • Douglas DeBoer, DVM, DACVD, Professor of Dermatology, University of Wisconsin–Madison 
  • Natalie Marks, DVM, CVJ, Veterinarian/Consultant, VCA Blum Animal Hospital 
  • Rosanna Marsella, DVM, DACVD, Professor of Dermatology, University of Florida 
  • Lindsay McKay, DVM, DACVD, Veterinary Dermatologist, VCA Arboretum View Animal Hospital 
  • Jennifer Schissler, DVM, MS, DACVD, Veterinary Dermatologist, Best Friends Animal Hospital Dermatology & Otology 
  • Phillip Thompson, DVM, Associate Veterinarian, BridgeMill Animal Hospital
  • Amelia White, DVM, MS, DACVD, Associate Clinical Professor of Dermatology, Auburn University 

In November 2021, a panel of experts convened to discuss how to successfully control itch and inflammation when treating acute flares of allergic and atopic dermatitis in dogs. They reviewed recent scientific discoveries and the published data from clinical field studies in client-owned dogs to provide evidence-based guidance on key points, selection of therapies, and management of canine allergic dermatitis.

They concluded that the anti-inflammatory and antipruritic effects of Apoquel® (oclacitinib tablet) make this immunomodulator an exceptional first-line treatment choice for acutely flaring, pruritic, and inflamed allergic and atopic dogs, regardless of disease severity. Published clinical studies indicate that Apoquel controlled pruritus (itch) and inflammation due to allergic and atopic dermatitis as effectively as steroids or cyclosporine.1-5 These proceedings will present supporting evidence and expert opinions to give practitioners confidence in their treatment approach and recommendations.

The Importance of Controlling Itch & Inflammation

Until about a decade ago, we had to rely on steroids for rapid and effective control of canine allergic and atopic dermatitis. We have come a long way in a short period of time. We now have targeted therapies specifically designed to treat allergic/atopic dermatitis. What does the evidence say about treating allergic pruritus and inflammation? Are steroids still the best option, or do targeted therapies perform as well?

“In general, I do not use steroids as the primary means to control my allergic and/ or atopic patients,” said Dr. Lindsay McKay. “There is always going to be a place for steroids in the management of atopic dermatitis and allergic disease in dogs. The key uses for me are going to be managing severe otitis and severe pododermatitis.”

Allergic skin disease continues to be challenging to manage. One basic principle remains true: We must ensure that our management plan for allergic and atopic dermatitis is grounded in current scientific evidence provided by randomized controlled clinical studies, where it exists.

Where Do We Start?

The presenting problem for most owners of allergic/atopic dogs is pruritus. They are frustrated, worried, and stressed, and they want their pet to get back to normal. Choosing the right medication to treat these dogs can help build owner confidence in our recommendations.

“When people typically come to see me, it is because the animal is itchy and destroying itself,” said Dr. Rosanna Marsella. “Controlling the itch is the most critical thing to the owner. That returns patient quality of life and gives a break to the owners who live with that pet so they can all get a good night’s sleep.”

Controlling the itch is the most critical thing to the owner. That returns patient quality of life and gives a break to the owners who live with that pet so they can all get a good night’s sleep.

“Itch is what drives my clients in. Successfully controlling the dog’s pruritus is the quickest way to earn their trust so they’ll actually listen to and follow our recommendations,” Dr. McKay said.

The experts were asked to participate in a poll during the roundtable. Responses were consistent and aligned with clinical experience. They agreed that, when selecting a treatment, their decision is based on how well it works. The factor they ranked most essential to success was speed of resolution of pruritus, closely followed by speed of resolution of inflammation and improvement of skin lesions (Figure 1). At the bottom end of the scale were cost of treatment and “broad” anti-inflammatory effect. Both received the lowest scores, with most experts feeling they are “not essential.”

FIGURE 1 In this poll, responses ranged from 1 to 5, with 1 being “nice to have but not essential” and 5 being “essential to success.”

Can We Do More?

Although itch may be what causes pets to be presented to the clinic, we know that inflammation plays a major role in allergic/atopic dermatitis and needs to be directly addressed as well.

Controlling inflammation in dogs with allergic/atopic dermatitis is important to:

  • Prevent disease progression
  • Decrease the likelihood of secondary infections of the skin and ears
  • Prevent recurrence of pruritus
  • Provide a long-term solution

“Atopic dermatitis has been described as a relentlessly progressive disease, and that’s because of inflammation,” Dr. McKay said.

Dr. Jeanne Budgin agreed that managing inflammation to prevent pruritus from returning is also vital. “While it is case-dependent, I think it’s about more than just providing itch relief, because we know that atopic dermatitis/allergic skin disease does tend to be chronic and relapsing,” she said, “so addressing the underlying inflammatory component is really important when it comes to preventing recurrence and providing long-term relief.”

Inflammation plays a major role in allergic/atopic dermatitis and needs to be directly addressed as well.

“We really need to control both itch and inflammation,” said Dr. Amelia White. “When we don’t, then not only is the quality of life for the pet and the owner quite poor, but now we’re going to have to deal with other complicating factors like infection.”

Clearly, product efficacy is most important. In terms of how the products work, the experts’ rankings in the poll tended to cluster toward a treatment that is targeted in its anti-inflammatory effect as being more essential to success.

The experts also noted that having a treatment that is systemic (rather than topical) and being able to use a single therapy throughout the treatment period were of moderate importance.

The Value of Systemic, Targeted Therapy

When allergens enter the body of an allergic patient, an exaggerated immune response that involves a wide variety of cell types is initiated, producing proteins such as cytokines, chemokines, and other inflammatory mediators.

Recent research has indicated that cytokines play a central role in most stages of the immune response, triggering and driving inflammation associated with allergic dermatitis. Many of the cytokines that are integral to atopic dermatitis amplify the inflammatory response through the Janus kinase 1 (JAK1) signaling pathway.

Along with our evolving understanding of the pathomechanisms of allergic/atopic dermatitis, there is another critically important concept we need to understand (see How Can a Targeted Therapy Have a Broad Effect?). Previously, we thought of the inflammatory response as being a linear process or directional cascade. Although that may still be true at the beginning of sensitization, we now know that these cytokines interact in a complex, interconnected inflammatory network, affecting many components in a multidirectional manner once clinical signs appear and the disease is established.

How Can a Targeted Therapy Have a Broad Effect?

A Complex, Multidirectional Network

We know that canine allergic/atopic dermatitis is a cytokine-driven disease, but rather than the old model of a unidirectional, linear cascade—the idea that if you interfere with one component, only what is directly downstream may be affected—the updated thinking is that cytokines interact with inflammatory cells within an interconnected and multidirectional network (Figure 2). This means that affecting one component does not only affect what is happening downstream but also potentially alongside and upstream.

“It’s not a linear relationship,” Dr. Nell Dalton said. “It goes in multiple directions.”

“Everything influences everything around it, whether it’s the skin barrier, cytokines, or infections,” said Dr. Ashley Bourgeois. “We know that these cytokines influence one another. Why does it matter? Because we know that this is a chronic disease that we can get these roller coasters of acute flares with, and we need to deal with it in our treatment—not only for the short term but long term as well.”

The Role of JAK1-Signaling Pathways in Allergic & Atopic Dermatitis

We have known for years that many of the cytokines that are released during the complex inflammatory response are dependent on JAK1 for signaling and activating cells, but we now know that JAK1 is also involved in several other important, interconnected pathways in this inflammatory network. This is why inhibiting JAK1 produces a significant effect on controlling itch and inflammation associated with allergic and atopic dermatitis (Figure 2).

FIGURE 2 When triggered by an allergen, keratinocytes, Langerhans cells, and Th2 lymphocytes produce multiple cytokines and mediators that activate a wide variety of inflammatory cells, which themselves contribute to amplification of the multidirectional network of inflammation. It is evident that many of the cytokines that activate cells involved in this process function through the JAK1 signaling pathway (shown in pink). These cytokines have effects on almost all the key cells involved. Thus, a JAK1 inhibitor (such as oclacitinib), while being a targeted therapy, can have broad effects within the milieu of events occurring in atopic/allergic dermatitis.
*This figure is intended to provide a clear and accurate framework of the concept without purporting to be a comprehensive and complete reflection of all events involved.

“JAK1 signaling is an extremely important pathway in allergic inflammation and itch in many—maybe even most—allergic dogs,” Dr. Doug DeBoer said. “It’s not the only pathway, but it’s maybe the most important pathway in allergic itch and inflammation.”

Apoquel specifically modulates JAK1-dependent, pruritogenic, and proinflammatory cytokines that play a major role in inflammation of the skin. In this way, Apoquel controls both pruritus and inflammation due to allergic and atopic dermatitis.1-5

Cytopoint® (canine allergic dermatitis immunotherapeutic) binds to and neutralizes interleukin (IL)-31.6 IL-31 plays a major role in pruritus, but it also induces a variety of proinflammatory cytokines from macrophages, including IL-1β, IL-8, tumor necrosis factor-alpha (TNFα), and IL-6, that can trigger inflammation.7 Thus, we now know that Cytopoint also has both an antipruritic and anti-inflammatory effect.8

What Does This New Knowledge Mean for Our Patients?

Using a specific therapy that targets these cytokines, rather than broadly inhibiting the immune system, is a good choice for our allergic and atopic patients.

“At the beginning, when everything’s on fire, you do need to inhibit a lot of cytokines. But you can do that with a more targeted therapy like Apoquel, compared to something less targeted like steroids,” Dr. White said. “We need a drug that is going to rapidly, effectively, and safely reduce inflammation and pruritus simultaneously, and I think we all agree that the best way to do that is by targeting multiple cytokines, since allergy is cytokine-mediated and there are usually many cytokines involved” (Figure 2, above).

“If we knew there was a broad treatment that was super safe and didn’t have side effects, then it might not be as much of a concern,” said Dr. Bourgeois. “With targeted treatment, we assume there are fewer side effects, so it makes pet owners (and us as doctors) feel more comfortable” (see Steroid Use in Allergic Dermatitis: There Are Costs for the Patient & the Pet Owner).

With the JAK1 signaling pathway being so important in the activation of cells involved in the allergic inflammatory network, targeting JAK1 specifically will have broad effects for canine patients with allergic or atopic dermatitis.

Steroid Use in Allergic Dermatitis: There Are Costs for the Patient & the Pet Owner

Short-Term Steroid Use Can Cause Side Effects

55% of dog owners report side effects with steroids.10 The most common include10,11:

  • Excessive urination
  • Increased thirst
  • Increased hunger (which may lead to weight gain)
  • Heightened stress and anxiety
Most Commonly Reported Adverse Events for Apoquel

The most commonly reported adverse events (from a 5-year pharmacovigilance review) are12:

  • Vomiting
  • Diarrhea
  • Lethargy
  • Anorexia
  • Blood work changes

The reported incidence rate for each individual adverse event was very rare, or <1 animal reacting per 10,000 dogs treated.13

How Do We Decide Which Drug to Use?

We now understand many of the mechanisms involved in allergic and atopic dermatitis, but there is still much to learn. However, examining a treatment’s mechanism of action and its effect on the cytokine network and hypothesizing on its clinical effects, while important and helpful, does have limitations. We also need to consider the literature to look at real-world results with patients in practice.

“We have to have some general idea of how treatments compare to each other in larger groups,” Dr. Marsella said. “One way is to run a study…and see if there are any statistically significant differences between treatments, with the understanding that you’re comparing 2 groups. Having said that, that does not equate to there being a cookie-cutter approach to this—that whatever treatment works based on that paper necessarily applies to a specific patient. But we have to have a place to start.”

The experts agreed that they’ve learned to not make assumptions about which treatment will work for a specific case. “I tell my clients [the inflammatory response with allergy] is like a soup,” Dr. Jennifer Schissler explained. “Different dogs have different soups. They have different things going on [in that soup]—some worse, some better —but it’s really complicated.”

“It is [like] a soup,” Dr. Doug DeBoer agreed. “It’s complex and multifactorial and is all orchestrated by the cytokine network.”

The experts concurred that treatment recommendations need to be based on comparative, head-to-head studies, which are the core of evidence-based medicine.

The experts concurred that treatment recommendations need to be based on comparative, head-to-head studies, which are the core of evidence-based medicine. Randomized controlled studies can provide compelling evidence of the efficacy of a product and the likelihood for success in a certain population of affected dogs (compared with placebo or a previous standard of care), but they do not guarantee the outcome in every patient in the real world.

Dr. DeBoer affirmed that the results of these studies can be applied to most, but not all, dogs. The results of controlled trials can provide the confidence practitioners need to make a recommendation.

The Evidence for Using Targeted Therapy: Apoquel Reduces Allergic Pruritus & Skin Lesions2,5

A single-blinded, randomized study by Gadeyne and colleagues2 evaluated the efficacy and safety of oclacitinib compared with prednisolone in 123 client-owned dogs with allergic dermatitis and moderate to severe pruritus. In this controlled study, oclacitinib worked as fast and as well as steroids in reducing pruritus and was as effective as steroids in reducing dermatitis associated with allergic dermatitis in dogs at all time points in the study.

Another single-blinded, randomized study by Little et al.5 compared the efficacy and safety of oclacitinib and cyclosporine for the control of canine atopic dermatitis in 226 client-owned dogs. In this controlled clinical trial, oclacitinib controlled pruritus faster than cyclosporine and controlled dermatitis as well as cyclosporine in dogs with atopic dermatitis.

What Do the Experts Think?

The experts reviewed these published studies and agreed that Apoquel performed as well as prednisolone and cyclosporine in controlling pruritus and inflammation due to allergic and atopic dermatitis.

In addition, they were presented with further subanalysis of the Apoquel and prednisolone comparative study, evaluating only dogs with dermatitis Visual Analogue Scale (VAS) scores indicating moderately severe to extremely severe dermatitis.9 The experts agreed that the findings support the original study conclusion that “Apoquel administered orally in the recommended dosing regimen reduced pruritus and clinical signs associated with allergic dermatitis to a level comparable to the efficacy of prednisolone administered at a dose of 0.5-1 mg/kg daily for 6 days,” even in dogs with more severe dermatitis.

Apoquel administered orally in the recommended dosing regimen reduced pruritus and clinical signs associated with allergic dermatitis to a level comparable to the efficacy of prednisolone administered at a dose of 0.5-1 mg/kg daily for 6 days, even in dogs with more severe dermatitis.

Dr. Bourgeois specifically appreciated that the studies showed that Apoquel worked as well as steroids for severe flares of canine allergic dermatitis. “We can use Apoquel in severe disease and still reduce inflammation, still make these pets comfortable, and not have those panic calls 3 days later because the pet’s urinating all over the house,” she said.

The experts were also impressed by the data showing the rapid onset of effect of Apoquel as compared with glucocorticoids in the clinical studies. Dr. Budgin acknowledged that it has impacted the way she practices. “I had always just been reaching for steroids for acute pruritus, pyotraumatic dermatitis (hotspots), things like that. I found the data to be really exciting; that was what launched me into feeling far more comfortable with using Apoquel,” she said.

Others agreed that the additional analysis from the oclacitinib and prednisolone (Gadeyne) comparative study gave them more evidence to support using Apoquel for moderate to severe allergic dermatitis in their canine patients. “It’s nice when the data show with numbers what we see clinically happening,” said Dr. White. “For those with severe inflammation due to allergic and atopic dermatitis, the study results showed that the dogs that received Apoquel performed as well as the dogs that received steroids.”

“I think that most veterinarians want the evidence-based data comparing the treatments head-to-head with our standard of care,” said Dr. McKay. “I think that turns a lot of people around in understanding why Apoquel is as good as steroids and why antihistamines don’t work.”

“Most pet owners know steroids come with a compromise. They’re not all that good; they affect every cell in the body, and immunologically, it ties one paw behind their back. We’re often dealing with infection at the same time, and with steroids, the dogs aren’t able to fight infection as well as they normally could,” Dr. Jay Crisman explained. “The Gadeyne [oclacitinib and prednisolone] study really is a comparative study that is conclusive and objective and answers those questions. It helps us put doubts aside; we don’t have to compromise like we used to with steroids when we see a dog with itch and inflammation due to allergic dermatitis.”

Cytopoint Controls Allergic Pruritus & Inflammation

Cytopoint has been shown to be effective in the treatment of dogs against allergic dermatitis and atopic dermatitis.6 Cytopoint binds to and neutralizes IL-31, a key cytokine that triggers activity within immune cells that leads to pruritus and inflammation due to allergic and atopic dermatitis.6,7

In a blinded, randomized clinical trial, Moyaert and colleagues8 evaluated the efficacy and safety of Cytopoint compared with cyclosporine in 274 client-owned dogs with chronic atopic dermatitis. Cytopoint provided rapid, long-lasting relief of allergic pruritus and skin lesions similar to cyclosporine in this controlled study.

What Do the Experts Think?

The experts agreed that the results of this study can give practitioners confidence in their choice of Cytopoint. “It’s important to provide relief quickly for the animal, as well as to have the owner buy into whatever plan we are going to propose for the medium and long-term,” Dr. Marsella said, “so I think that the speed of action [of the chosen therapy] is very relevant.”

“If a dog favorably responds to Cytopoint, then we are going to see a decrease in inflammation due to allergic dermatitis, especially as it relates to self-induced excoriations,” Dr. White concluded. “But I do think that we also see in some dogs a decrease in inflammation beyond the itching and scratching behavior.”

Additional Tips to Help You Succeed

Beyond following the evidence-based data from published controlled studies and the science as it evolves, what else can we do to set up ourselves and our allergic/atopic dermatitis patients for success?

1. Set Client Expectations

The experts emphasized the importance of educating clients about allergic dermatitis, including setting the expectation early in the course of the disease that chronic management will be required. As Dr. DeBoer said, “I don’t think a general practice veterinarian can say often enough and early enough, ‘I think your dog is allergic. I can offer you a treatment for that, but you need to understand that your dog’s allergies are not going to go away. This is a chronic disease.’”

Dr. Schissler makes sure her clients understand that as well, both during visits and on the discharge instructions. She explains that “allergic dermatitis is a lifelong condition that will require lifelong treatment and may require treatment adjustments.”

Dr. Schissler explains that “allergic dermatitis is a lifelong condition that will require lifelong treatment and may require treatment adjustments.”

Dr. Natalie Marks conveys that allergic dermatitis is an inflammatory disease that requires more than a one-and-done approach. “Hopefully we can set the expectation that this is a journey,” she said. “It’s an inflammatory disease. That way, our clients get a sense of the weight of the disease so they understand the compliance aspect.”

2. Provide a Long-Term Plan

Addressing both itch and inflammation due to allergic and atopic dermatitis correctly is a good start. But that’s not enough. The experts all felt that there is a need for a longterm plan.

“We need to be more proactive in managing patients with allergic and atopic dermatitis,” said Dr. McKay. “We need to have a long-term strategy for our patients for the management to be successful.”

Dr. Phil Thompson also reminds his clients that the plan for managing canine allergic dermatitis is a living thing. “That plan will change based on what the patient’s needs are and what’s going on in that moment,” he said.

3. Refer Early

“Early referral to a veterinary dermatologist who will work in conjunction with the client’s primary care veterinarian can be beneficial in helping to manage secondary infections as well,” Dr. Budgin said. She suggested educating clients that referral is not a sign that their veterinarian has given up but rather wants to provide their pet with the best possible management for this chronic disease.

Dr. Bourgeois would certainly like to see these cases a bit sooner, “so we can help with that plan through the use of medications like Apoquel and Cytopoint, instead of allergy testing them when they’re 8 years old and we’re starting to already see the progression of that disease.”

4. Know When to Perform a Diagnostic Investigation

The experts pointed out that every time a patient flares, a diagnostic investigation needs to be top of mind (Figure 3). Flares are periods of worsening of disease. Continuing the anchor therapy during the investigation is essential to keep the dog comfortable and to improve owner compliance with diagnostic trials.

“We can’t say too often in evaluating flares of atopic dermatitis: Make certain that parasite control and infection control are underway,” said Dr. DeBoer.

“And make sure you identify if it’s a food flare as well,” Dr. McKay noted, “That diagnostic workup that we do in the beginning needs to be running through our mind every time patients have a flare. Is it parasites? Is it infection? Is it food?”

Dr. Mike Canfield suggests that, when a patient is presented with a flare, the practitioner should investigate possible causes, such as lack of compliance with topical therapy or an unresolved methicillin-resistant Staphylococcus infection.

5. Recognize that Flares Happen

Allergic/atopic dermatitis is not curable, and dogs with the disease are predisposed to flaring. “We know that even nonlesional skin in atopic dogs is abnormal. The components of a flare are always there waiting to develop; [the patients are] always on the verge of a flare,” said Dr. McKay.

“We know there will be flares…atopic dermatitis is a flare disease,” Dr. Thompson said. “Setting the expectation— that client communication part that’s so important for all of dermatology—makes these cases easier to handle.”

“Just because we have that little thing that gets ahead of us—whatever it is—life gets in the way and [the client] forgot flea control, for instance, we give up on a therapy,” Dr. Bourgeois said. “Plenty of pets flare even if they’re on chronic steroids.”

The important point is not to give up on a therapy; you may just need a little extra help for a while.

Key Takeaways

Veterinarians Need to Be Able to Rely on Clinical Evidence

The experts agreed that the data from the controlled studies, along with our new understanding of the inflammatory cytokine network being interconnected and multidirectional, support the choice of Apoquel to treat even a moderate to severe flare of canine allergic and atopic dermatitis.2,5,9

“We want to be as targeted as we can but also as broad as we need to be. We have something that is targeted specifically to interleukin-31, which would be Cytopoint, and it works very well for [particular] patients. [If] I need something that works a little more broadly, [that] would be Apoquel,” said Dr. Thompson. “Whether it’s Cytopoint, Apoquel, or allergen-specific immunotherapy, any of those 3 [therapies] are significantly more targeted than corticosteroids.”

"Apoquel and Cytopoint are some of the best tools that we have for controlling flares of allergic/atopic dermatitis in our canine patients."

“When I think about a therapy, I want it to be safe, but I want it to broadly cover those cytokines,” Dr. White explained. “To reduce inflammation and reduce itch at the same time and be safe to the patient, but also have few side effects, would be ideal.”

“When Apoquel first came out, it was so terrific to have a product that stopped the allergic [pruritus] so fast and effectively,” said Dr. Thompson. “With time, we saw that it really has great anti-inflammatory effects, and that was understandable as we learned more about the pathways involved in allergic dermatitis. It’s the same with Cytopoint, launched on the basis of providing great pruritus relief—which it does—but with use and observation, we see a decrease in inflammation as well, and the new science helps make sense of that.”

The Data Do Not Support the Need to Use Steroids for Most Flares

Current data show that, in many cases, regardless of the degree of disease severity—whether it’s a mild or moderate to severe flare—Apoquel works just as well as steroids as a first-line treatment to reduce itch and inflammation due to allergic and atopic dermatitis in dogs.2,9

“In a study, Apoquel worked as quickly and as effectively as steroids for managing pruritus and dermatitis,” said Dr. McKay. “Apoquel provided the antipruritic and antiinflammatory benefits that you’re looking for, and we can get away from the side effects of steroids that we don’t like and we know are very distasteful to our clients” (see Steroid Use in Allergic Dermatitis: There Are Costs for the Patient & the Pet Owner, above).

“Apoquel and Cytopoint are some of the best tools that we have for controlling flares of allergic/atopic dermatitis in our canine patients,” Dr. Marsella agreed.


For Apoquel’s full prescribing information, please visit apoquel.com/pi.


References

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