June 2021   |   Volume 19   |   Issue 4

Fine-Needle Biopsy Sample Collection & Handling Errors

in this issue

in this issue

Top 5 Fine-Needle Biopsy Sample Collection & Handling Errors

Top 5 Dermatologic Indications for Pentoxifylline in Dogs

Suspected Food Allergy in Dogs

Euthanasia Protocols

Pelvic Limb Lameness in a Cat

Differential Diagnosis: Neutrophilia

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Galliprant CB June 2021

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Claro CB June 2021

Top 5 Dermatologic Indications for Pentoxifylline in Dogs

Sarah Lewis, DVM, MS, Auburn University

Robert Kennis, DVM, DACVD, MS, Auburn University

Dermatology

|Peer Reviewed

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Top 5 Dermatologic Indications for Pentoxifylline in Dogs

Pentoxifylline is a methylxanthine derivative that inhibits phosphodiesterase to raise intracellular cyclic adenosine monophosphate levels1; this can have many global effects, including improved circulation and reduced inflammation.1 Pentoxifylline inhibits RBC deformability, microvascular constriction, and thrombus formation1; decreases proinflammatory cytokine production, neutrophil degranulation, natural killer cell activity, leukocyte adhesion, chemotaxis, and adherence to keratinocytes1-3; and stimulates fibroblasts to produce collagenase and promote wound healing.1,2 Cytokines inhibited by pentoxifylline include tumor necrosis factor-α, interferon-γ, interleukin-1 (IL-1), IL-6, IL-8, and IL-10.1

Pentoxifylline (10-30 mg/kg PO every 8 to 12 hours) has a reported elimination half-life of 24 to 404 minutes that supports 8-hour administration.4-6 In dogs, oral bioavailability is variable and reported to be 15% to 50%.5,6 Pentoxifylline is available as a 400-mg extended-release tablet and is commonly halved or quartered to achieve the intended dosage.5,6 No controlled studies have directly investigated the pharmacokinetic effects of breaking the extended-release tablet. Pentoxifylline is generally well-tolerated in dogs, and GI upset is the most commonly reported adverse effect.5,6 Anecdotal reported use in veterinary medicine is vast; however, peer-reviewed studies evaluating its efficacy for the treatment of specific diseases are limited and generally retrospective. Based on anecdotal evidence in human and veterinary medicine, there is believed to be a lag in onset to clinical effect that may last several months.6-8 Previously, concerns about cost limited the use of pentoxifylline in veterinary medicine, but affordable generic formulations are now available. 

Following are 5 common uses of pentoxifylline in veterinary dermatology according to the authors.

1

Cutaneous Vasculitis

Cutaneous vasculitis refers to inflammation of the blood vessels in the skin (Figure 1) that results in altered blood flow and ischemic necrosis of the skin (Figure 2).9 The condition may be idiopathic or caused by adverse drug reaction, infection, insect bite, or neoplasia.8 Treatment should address the underlying cause and repair tissue damage.9 Pentoxifylline is an ideal treatment (regardless of cause) because of its effect on perfusion and inflammation.

Because pentoxifylline has a potential delayed onset of effect, it is often combined with other drugs (eg, glucocorticoids).9 In a retrospective study,10 9 of 19 dogs with vasculitis were treated with pentoxifylline (10-20 mg/kg PO every 12 hours) alone (1 dog) or in combination (8 dogs) with prednisone (1.5-3 mg/kg/day) with variable success. Six dogs had complete resolution, 2 had partial resolution, and 1 failed to respond. Of the 6 dogs with complete resolution, 3 relapsed when prednisone was tapered, suggesting that pentoxifylline may be insufficient when used alone to treat vasculitis.10 Insufficient dosage and frequency could explain the limited success and lack of response in 3 dogs.10 Despite reports of variable success, pentoxifylline is often used for the treatment of vasculitis.

Multifocal to coalescing erythematous macules on the ventral abdomen of a dog with cutaneous vasculitis. Because the lesion does not blanch on diascopy, it is likely due to vasculitis or hemorrhage. Image courtesy of Amelia White, Auburn University
Multifocal to coalescing erythematous macules on the ventral abdomen of a dog with cutaneous vasculitis. Because the lesion does not blanch on diascopy, it is likely due to vasculitis or hemorrhage. Image courtesy of Amelia White, Auburn University

FIGURE 1 Multifocal to coalescing erythematous macules on the ventral abdomen of a dog with cutaneous vasculitis. Because the lesion does not blanch on diascopy, it is likely due to vasculitis or hemorrhage. Image courtesy of Amelia White, Auburn University

FIGURE 1 Multifocal to coalescing erythematous macules on the ventral abdomen of a dog with cutaneous vasculitis. Because the lesion does not blanch on diascopy, it is likely due to vasculitis or hemorrhage. Image courtesy of Amelia White, Auburn University

Full-thickness dermal necrosis on the hock of a patient with a neutrophilic necrotizing vasculitis suspected to be secondary to a spider bite. Pentoxifylline (25 mg/kg PO every 12 hours) and open wound management were provided. Image courtesy of Karly Hicks, Auburn University
Full-thickness dermal necrosis on the hock of a patient with a neutrophilic necrotizing vasculitis suspected to be secondary to a spider bite. Pentoxifylline (25 mg/kg PO every 12 hours) and open wound management were provided. Image courtesy of Karly Hicks, Auburn University

FIGURE 2 Full-thickness dermal necrosis on the hock of a patient with a neutrophilic necrotizing vasculitis suspected to be secondary to a spider bite. Pentoxifylline (25 mg/kg PO every 12 hours) and open wound management were provided. Image courtesy of Karly Hicks, Auburn University

FIGURE 2 Full-thickness dermal necrosis on the hock of a patient with a neutrophilic necrotizing vasculitis suspected to be secondary to a spider bite. Pentoxifylline (25 mg/kg PO every 12 hours) and open wound management were provided. Image courtesy of Karly Hicks, Auburn University

2

Canine Familial Dermatomyositis

Canine familial dermatomyositis (CFD) is an inherited, ischemic disease of the skin, blood vessels, and muscle that predominantly affects Shetland sheepdogs and collies; however, other dog breeds can also be affected.11 Lesions occur in the first few months of life and can vary from minor alopecia (Figure 3) to severe dermal ulceration and muscle atrophy. CFD is incurable; many treatments have been attempted with limited success. In a study, 10 dogs with CFD had partial or complete resolution of cutaneous lesions after receiving pentoxifylline (25 mg/kg PO every 12 hours for 12 weeks).12 The median time to initial response was 6 weeks, supporting a lag in onset of effect.12 No adverse effects, including clinicopathologic abnormalities, were observed, further supporting the relative safety of pentoxifylline as compared with other therapeutic options.12

An alopecic, ischemic lesion on the bridge of the nose due to dermatomyositis
An alopecic, ischemic lesion on the bridge of the nose due to dermatomyositis

FIGURE 3 An alopecic, ischemic lesion on the bridge of the nose due to dermatomyositis

FIGURE 3 An alopecic, ischemic lesion on the bridge of the nose due to dermatomyositis

3

Other Ischemic Dermatopathies

Ischemic dermatopathy refers to several clinical syndromes characterized by overall nutrient and oxygen deficiency in the skin,13 including CFD, rabies-vaccine–induced vasculitis, vaccine-associated ischemic dermatopathy, familial cutaneous vasculopathy in German shepherd dogs, pinnal vasculitis (Figure 4), and idiopathic ischemic dermatopathy.13 In a study, 3 dogs with rabies-vaccine–induced vasculitis had partial to complete hair regrowth 12 to 16 weeks after receiving pentoxifylline (15 mg/kg PO every 12 hours) combined with prednisone (0.8-3 mg/kg/day PO).10 In a retrospective study of 177 dogs with ischemic dermatopathy, the majority of dogs (91.3%) were treated with either pentoxifylline alone or as adjunctive therapy, with a mean dosage of 47.12 mg/kg/day PO (range, 18-112.5 mg/kg/day PO).13 Despite common use, no difference was found between dogs treated and dogs not treated with pentoxifylline. It was concluded that the retrospective nature of the study and variability in dosing regimens could explain this finding. Additional prospective, placebo-controlled studies are needed to determine the effectiveness of pentoxifylline in the treatment of ischemic dermatopathies. Despite limited evidence in the literature, the hemorrheologic properties of pentoxifylline could be favorable for the management of ischemic dermatopathies.

Bilaterally symmetric crusted lesions at the apex of the pinnae, consistent with pinnal vasculitis
Bilaterally symmetric crusted lesions at the apex of the pinnae, consistent with pinnal vasculitis

FIGURE 4 Bilaterally symmetric crusted lesions at the apex of the pinnae, consistent with pinnal vasculitis

FIGURE 4 Bilaterally symmetric crusted lesions at the apex of the pinnae, consistent with pinnal vasculitis

4

Allergic Contact Dermatitis

Allergic contact dermatitis (ACD) is a type IV hypersensitivity reaction.8,14 Reported causes of ACD in dogs include ingestion of plants, topical medications, detergents, cleansers, fibers, and plastic.8,14 Pentoxifylline inhibits tumor necrosis factor-α, which is a critical mediator of ACD.1,14 Pentoxifylline (10 mg/kg PO every 12 hours) was protective in preventing clinical signs in 3 dogs with known contact allergy to plants in the Commelinaceae family.14 A clinical effect was observed within 2 days of onset of therapy and persisted for 7 days following discontinuation of therapy.14 Treatment duration was limited to 3 to 5 weeks due to the cost of therapy.14 Pentoxifylline has become less cost-prohibitive; thus, it can be a reasonable choice for prevention of clinical signs of ACD when avoidance is not possible. Major limitations of this study were the few number of dogs included and its retrospective nature. Additional investigations are required to determine the effectiveness of pentoxifylline in the treatment of ACD.

5

Atopic Dermatitis

Canine atopic dermatitis (CAD) is a common allergic dermatosis characterized by hypersensitivity to environmental allergens, primarily mediated by immunoglobulin E (IgE).15 CAD can be challenging for the patient, pet owner, and clinician despite available pharmacologic management options. Although pentoxifylline is not considered a mainstay for management of CAD, limited research suggests it may have value as adjunctive therapy.16,17 One study in normal dogs demonstrated that pentoxifylline inhibited late-phase inflammation by inhibiting IgE-mediated mast cell degranulation and eosinophil recruitment at the site’s wheal formation.18 These findings suggest pentoxifylline may have some effect in managing IgE-mediated inflammatory diseases. A double-blinded, placebo-controlled, crossover study of 10 atopic dogs showed that pentoxifylline (10 mg/kg PO every 12 hours) reduced pruritus scores by 50% in one-third of dogs over 4 weeks.16 Dexamethasone and pentoxifylline have an in vitro synergistic effect on cytokine production via human leukocytes.19 Pentoxifylline may have use as a steroid-sparing agent in dogs with CAD, but further studies are warranted to confirm its efficacy.15,16

In addition to these indications, anecdotal evidence suggests pentoxifylline may be useful for treatment of vesicular cutaneous lupus erythematosus, erythema multiforme, acral lick dermatitis, and metatarsal fistulae in German shepherd dogs.8 Recent evidence evaluating the use of pentoxifylline in the treatment of dermal arteritis of the nasal philtrum and symmetric lupoid onychodystrophy suggests this drug may be an effective sole or adjunctive treatment in the management of these diseases.20,21 Controlled clinical studies regarding the efficacy of pentoxifylline are lacking. Because of its relatively affordable cost and minimal adverse effects, pentoxifylline may be a useful adjunct therapeutic for dermatologic conditions in which improved microcirculation and reduced inflammation are desired.

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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Hill's CB June 2021

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BI Vaccines CB June 2021

Suspected Food Allergy in Dogs

Elizabeth R. Drake, DVM, DACVD, University of Tennessee

Nutrition

|Peer Reviewed

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Suspected Food Allergy in Dogs
Clinician's Brief
Clinician's Brief

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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Dechra CB June 2021

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Euthanasia Protocols

Kathleen Cooney, DVM, MS, CHPV, CCFP, Companion Animal Euthanasia Training Academy, Loveland, Colorado

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Euthanasia Protocols

Euthanasia is a medical procedure to end life, typically via IV administration of a pentobarbital anesthetic overdose or with select organ injection in anesthetized patients. Euthanasia is chosen for a variety of reasons when continued life is deemed unacceptable, including to end suffering in patients with physical and/or emotional problems that lead to a significant decrease in quality of life and well-being. Veterinary professionals must evaluate what is in the best interest of the patient. If euthanasia is not deemed necessary, an alternative approach to maintain quality of life is recommended.

Guidelines are available for euthanasia procedures in animals,1 including with IV and intraorgan administration of a pentobarbital anesthetic. It is imperative that any euthanasia technique deliver a pain- and stress-free death.1 Different euthanasia techniques can result in shorter or longer times to death depending on the absorption rate of pentobarbital in the body and, ultimately, the brain (Table). Multiple techniques are available, and it is important to quickly modify techniques if necessary. Choice of technique depends on the signalment and physical condition of the patient, requirement for pre-euthanasia sedation or anesthesia, availability of required supplies, clinician comfort and skill, and possible need for postmortem examination.

Successful euthanasia procedures involve use of the correct supplies, attention to patient comfort, and knowledge of administration methodology. A sedative or anesthetic agent should be given prior to euthanasia to reduce the risk for pain and stress. Common pre-euthanasia sedatives include benzodiazepines (eg, midazolam), opioids (eg, butorphanol), α2 agonists (eg, dexmedetomidine), and phenothiazines (eg, acepromazine). Common pre-euthanasia anesthetics include dissociatives (eg, ketamine), hypnotics (eg, propofol), neurosteroids (eg, alfaxalone), and anesthetic gases (eg, isoflurane).

Clinicians are required to pronounce death by auscultating the heart and verifying apnea. Additional indicators include lack of corneal reflex and onset of rigor mortis.

TABLE

PENTOBARBITAL DOSE FOR DIFFERENT INJECTION TECHNIQUES4

Route of Administration Dose* (per 10-lb [4.5-kg] body weight) Time to Death
Intravenous 85 mg/kg 1 mL <1 minute
Intracardiac 85 mg/kg 1 mL <1 minute
Intrarenal 255 mg/kg 3 mL <1 minute
Intrahepatic 170 mg/kg 2 mL <5 minutes
Intraperitoneal 255 mg/kg 3 mL <15 minutes (highly variable)
*These doses are based on a 390 mg/mL pentobarbital concentration. A greater volume of solution may be needed if exact patient weight is unknown.

Injection Site/Needle Placement

The most common euthanasia techniques in dogs and cats require the euthanasia solution be injected into the venous system; this can be done via administration of solution directly in the vein or in areas of the body (eg, intraorgan) where the venous system moves the drug to the brain to induce death. Decisions about ideal technique should be based on patient signalment. Injection techniques described in this article can be used in cats and dogs.

Intravenous Injection

For IV injection, the preferred injection sites are the cephalic veins of the thoracic limbs, the medial (cats) and lateral saphenous (dogs) veins of the pelvic limbs, and the dorsal pedal vein of the foot. It is common to inject near the distal end of the vein, moving proximally as needed. All veins are acceptable to use if patent and easy to locate without causing additional stress to the patient or pet owner. Needle size varies from 18- to 22-gauge.

Intracardiac Injection

In most dogs and cats, the heart is between the third to sixth intercostal space and approximately one-third the distance dorsally to the thorax from the sternum. When auscultating for the heart, the loudest region (also called the point of maximum intensity [PMI]) should be identified. The thoracic limb can also be used to help identify the injection site. Combining the location of the PMI with the position of the elbow and visualizing the intercostal spaces can help ensure accurate placement of the needle directly in the heart. Needle length should be long enough to reach any heart chamber (ventricles are preferred); a 1- to 3-inch needle is usually sufficient for most dog and cat breeds. The syringe should be large enough to hold both the pentobarbital solution and the blood obtained on aspiration during needle placement. Needle size is typically 18-gauge. This technique requires the patient be unconscious.

Intrarenal Injection

For intrarenal injection, either kidney may be used. If time of death appears prolonged, another injection may be administered in either kidney. Needle size is typically 18-gauge. This technique requires the patient be unconscious.

Intrahepatic Injection

For intrahepatic injection, the xyphoid process should be located; the liver is typically dorsal to the xyphoid process. If time of death appears prolonged, another injection may be administered. Needle size is typically 18-gauge. This technique requires the patient be unconscious.

Intraperitoneal Injection

Pure pentobarbital solution is commonly administered intraperitoneal to conscious patients, but care should be taken to prevent the solution from entering neighboring organs, as intraorgan injection is painful. Use of pre-euthanasia sedation or anesthesia can help prevent injection pain or discomfort. Intraperitoneal injection results in a longer time to death, as the solution must be absorbed across serosal linings to enter the blood stream. Abdominal fluid and fat may slow absorption further. Needle size varies from 18- to 22-gauge.

Alternative Methods

Oral administration of pentobarbital and use of nonpentobarbital drug choices (when safe body disposition is unavailable) are gaining popularity as alternative euthanasia methods. Oral pentobarbital (255 mg/kg) can be a viable option for some patients, including those that have tendencies toward aggression or that are highly aversive to needles. Pentobarbital appears to have an unpleasant taste and is best hidden in food or drug capsules. Nonpentobarbital drug choices include overdoses of other anesthetics (eg, propofol).


STEP-BY-STEP

EUTHANASIA PROTOCOLS


WHAT YOU WILL NEED

  • Pentobarbital solution
  • Sedative or anesthetic drugs
  • 18- to 27-gauge needle
  • 1- to 35-mL syringe
  • IV or butterfly, 20- to 24-gauge catheter
  • Tourniquet
  • Clippers (optional)
  • Adhesive tape (optional)
  • Male adapters (optional)
  • Extension sets (optional)

INTRAVENOUS INJECTION

STEP 1

Administer a sedative or anesthetic agent.


STEP 2

Place the sedated/anesthetized patient in lateral recumbency. Clip the hair from the area of the injection site, place a secure tourniquet, and massage the area to increase blood in the vein for better visibility and accessibility.


STEP 3

Using a needle and syringe, a butterfly catheter, or a secured indwelling IV catheter, directly administer the pentobarbital solution at a rate of 1 mL/second (conscious patient) or 0.1 mL/second (heavily sedated/anesthetized patient).

Clinician's Brief

STEP 4

Following injection, flush the catheter with saline to remove the pentobarbital solution.


STEP 5

Check for signs of death; if not present, readminister the injection.

AUTHOR INSIGHT

A slower rate of administration in sedated patients can reduce active signs of death.


INTRACARDIAC INJECTION

STEP 1

Administer an anesthetic agent to induce unconsciousness.


STEP 2

Place the anesthetized patient in lateral recumbency to identify the injection site. If auscultating the heart, identify the PMI. Grasp the antebrachium and press the elbow up to the chest wall to simulate its position as if the patient were standing. Insert the needle at the point where the elbow meets the chest.


STEP 3

Keep the needle in a perpendicular position to the chest wall and insert it between the ribs. Maintain negative pressure on the syringe as the needle advances, until blood is freely aspirated, then inject the solution.

Clinician's Brief

STEP 4

Remove the needle slowly after all solution has been administered.


STEP 5

Check for signs of death; if not present, readminister the injection.

AUTHOR INSIGHT

If the owner is present, consider use of a small extension set to shield blood from view. Curl the extension set in the palm of the hand and keep the syringe low and out of sight.2

Clinician's Brief

INTRARENAL INJECTION

STEP 1

Administer an anesthetic agent to induce unconsciousness.


STEP 2

Place the anesthetized patient in lateral recumbency and gently run hands along the abdomen to locate the kidneys; check that no muscle tensing or resistance to palpation is evident.


STEP 3

Using fingertips, cup the kidney and raise it so that it is parallel with the spine. Ensure the kidney remains immobile during the entire procedure.


STEP 4

Using a needle with a length that can reach the kidney (1-1.5–inch, depending on patient size), insert the needle tip into the renal cortical or medullary tissue, and slowly inject the solution. Palpate for swelling of the kidney. Continue injecting until the syringe is empty.

Clinician's Brief

STEP 5

If swelling is not palpated during the injection, redirect the needle slightly in multiple directions to fill the kidney.


STEP 6

Check for signs of death; if not present, readminister the injection.

AUTHOR INSIGHT

When injecting the solution, the kidney should swell with the pressure of the solution against the renal capsule. Kidney swelling does not guarantee immediate death, but it does increase the possibility for a shorter time to death.3 Death may occur before completion of the injection.


INTRAHEPATIC INJECTION

STEP 1

Administer an anesthetic agent to induce unconsciousness.


STEP 2

Place the anesthetized patient in lateral recumbency and locate the xyphoid process.


STEP 3

Using a 1- to 3-inch needle, depending on patient size, insert the needle tip on either side of the xyphoid process at a 45-degree angle cranially.

Clinician's Brief

STEP 4

Slowly inject the solution into the liver region. Redirect the needle as needed to infuse the solution in more of the hepatic tissue.


STEP 5

After administration, slowly remove the needle.


STEP 6

Check for signs of death; if not present, readminister the injection.


INTRAPERITONEAL INJECTION

STEP 1

Administer a sedative or anesthetic agent.

STEP 2

Locate the injection site either slightly caudal and to the right of the umbilicus or midabdomen in the flank region.


STEP 3

Insert a 1- to 1.5-inch needle through the abdominal wall. Pull the syringe plunger to aspirate for negative pressure.

Clinician's Brief

STEP 4

If no blood or fluid is aspirated, administer the solution.


STEP 5

Check for signs of death. If the patient remains breathing after 10 to 15 minutes, readminister the injection or change to an intraorgan injection with the patient in an unconscious state.

AUTHOR INSIGHT

When giving intraorgan injections, it is recommended to slowly administer a small amount of solution (up to 0.5 mL) in the area to assess depth of sleep (eg, no response to stimuli). If no immediate response is observed, the remainder of the solution can be administered to effect.

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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Antech CB June 2021

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Bionote CB June 2021

Urinary Shedding: The Real Hidden Risk of Leptospirosis Transmission

Natalie L. Marks, DVM, CVJ

Infectious Disease

|Sponsored

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Urinary Shedding: The Real Hidden Risk of Leptospirosis Transmission
Sponsored by Merck Animal Health

Leptospirosis is the most common infectious zoonotic disease worldwide and is considered to be a re-emerging disease and significant threat to canine health in all regions of the United States.1 Although veterinarians are commonly educated on the acute presentations of canine leptospirosis (eg, inappetence, vomiting, fever, lethargy), many may not be aware of the chronic carrier state that can produce idiopathic polyuria/polydipsia or result in no clinical signs at all.1 These chronic carriers pose a risk to humans in their household, veterinary teams, and other dogs in the community.2

Prevention of disease is best achieved through an understanding of how a patient becomes infected and the pathophysiology of the organism. Direct transmission of Leptospira spp occurs when dogs come in contact with infected urine or ingest infected tissue. Once infection ensues, the spirochetes travel the bloodstream for several days, creating leptospiremia; after this phase, they can infect and set up residence in other organs, including the kidneys.3 This can create a carrier state. Shedding of leptospires in the urine (ie, leptospiruria) can persist for ≤3 months if there is inappropriate or absence of appropriate treatment.4

The significance of the chronic carrier state in the canine population could easily be underestimated, since these dogs may show no clinical signs of disease. In one study, PCR testing demonstrated that 8% of dog from a group of 500 seen at a veterinary teaching hospital excreted leptospires in the urine.5 Only 10% of the shedding dogs had clinical signs of leptospirosis.

In one study, PCR testing demonstrated that 8% of dog from a group of 500 seen at a veterinary teaching hospital excreted leptospires in the urine.

These chronic carriers pose a substantial hidden risk for transmission within homes, dog parks, kennels, and daycares. In our role as public health officers, it is imperative to choose a vaccine that prevents not only mortality but also leptospiremia and subsequent leptospiruria and urinary shedding. At the 2016 International Society for Companion Animal Infectious Diseases meeting, researchers presented a set of challenge studies that were conducted using 2 groups of puppies: those appropriately vaccinated as compared with a placebo group and then challenged. Urine samples were evaluated over 35 days and blood samples over 10 days. Results indicated no evidence of leptospiremia or leptospiruria in any of the vaccinated puppies, firmly supporting the claim of prevention of urinary shedding.6 Choosing this vaccination strategy provides the best chance for protection for patients, pet parents, and veterinary team members.

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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T8 Keto CB June 2021

Effective Treatment of Snake Mites

Sara J. Sokolik, DVM, Avian and Exotic Animal Care, Raleigh, North Carolina

Dan H. Johnson, DVM, DABVP (ECM), Avian and Exotic Animal Care, Raleigh, North Carolina

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Effective Treatment of Snake Mites

In the Literature

Fuantos Gámez BA, Romero Núñez C, Sheinberg Waisburd G, et al. Successful treatment of Ophionyssus natricis with afoxolaner in two Burmese pythons (Python molurus bivittatus). Vet Dermatol. 2020;31(6):496-e131.


FROM THE PAGE …

Ophionyssus natricis is a common mite that affects captive snakes. Mite infestations can lead to irregularities in the scales, dysecdysis, anemia, and clinical signs such as lethargy and decreased appetite. O natricis may also be a vector for the arenavirus responsible for boid inclusion body disease.1 Mites can be transmitted via direct contact with infested snakes or soiled substrate and furniture. Previously documented treatment options included pyrethrins and pyrethroids, fipronil, selamectin, and ivermectin; however, these therapies have associated risks and limitations and may not be recommended for every patient.

Afoxolaner is a commonly used oral treatment for fleas and ticks in dogs. This study evaluated the effectiveness of afoxolaner in the treatment of 2 Burmese pythons with O natricis mite infestation. Both snakes were treated with a single dose of afoxolaner (2 mg/kg body weight PO) through an orogastric tube. There was no evidence of live O natricis in either snake within 3 days, indicating rapid onset of action. Dead mites were found in the snake enclosures for up to 30 days. No adverse effects were observed.

Because this is a single-dose treatment option, it allows for reduced stress due to less handling, lessened chance of toxicity, and elimination of risks associated with compliance failure of at-home treatments. In addition, measuring and administering an oral treatment is typically a more specific administration method as compared with topically applying drugs. Resistance has been reported with older acaricides but not with afoxolaner.


… TO YOUR PATIENTS

Key pearls to put into practice:

1

It is important to verify O natricis mite infestation with morphometric identification under a microscope.

 

2

Care should be taken when tube-feeding oral medication to snakes. Staff should be comfortable with the procedure, and pet owners should be educated about possible risks, which include mucosal damage, esophageal perforation, regurgitation, and aspiration. When medicating via tube, it is important to flush the tube with enough food or fluid so the intended dose is fully administered to the patient (ie, none of the oral dose remains in the tube).

3

Rechecks should be performed 1 month following treatment to ensure no mites remain.

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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Heartgard CB June 2021

Blastomyces dermatitidis from a Needlestick Injury

Radford G. Davis, DVM, MPH, DACVPM, Iowa State University

Infectious Disease

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<em>Blastomyces dermatitidis</em> from a Needlestick Injury

In the literature

Ghatage P, Pierce KK, Wojewoda C, et al. A veterinarian from Vermont presenting with a painful right index finger following a needlestick injury that occurred while caring for a dog. Clin Infect Dis. 2020;71(6):1577-1599.


FROM THE PAGE…

Many occupational hazards (including animal bites, scratches, crushing and kicking injuries, and needlestick and other sharps injuries) can affect clinicians and veterinary staff. Needlestick injuries (NSIs) appear to be underdocumented but are common in the clinic, with most clinicians reporting at least 1 NSI, if not more, in their career.1 Consequences of an NSI can include infection, local inflammation, localized necrosis, skin slough, nerve damage, allergic reaction, miscarriage, systemic effects, and/or even death.1,2 Zoonoses transmission via needlestick and sharps injuries has been associated with Bartonella spp, Brucella abortus RB51 vaccine, and Blastomyces spp, among others.1-7 Blastomyces dermatitidis has also been transmitted via dog bites.8

In this case, a clinician suffered an NSI to the right index finger from a 21-gauge needle after aspirating fluid from a subcutaneous cystic mass in a dog with systemic blastomycosis. Swelling, tenderness, erythema, pain, and limited range of motion of the distal interphalangeal joint ensued. Purulent exudate was expressed from the finger during surgery, and biopsies were taken. Staining of tissues revealed broad-based budding between mother and daughter cells consistent with B dermatitidis, which was confirmed via isolation. 

The usual method of infection in humans with B dermatitidis is via inhalation of the conidia, which transforms into the yeast phase and can spread hematogenously throughout the body.9 Humans may have no clinical signs, show nonspecific signs (eg, cough, fever, malaise, fatigue, weight loss), or develop more severe disease.9 Pneumonia is the most common manifestation of blastomycosis in humans, with skin lesions being next most common.9 Abscesses frequently form in the skin and subcutaneous tissues, but they can also form in the brain, bones, prostate, or other organs.9 

Dogs and, less commonly, cats can develop B dermatitidis infection.10 Young, male dogs of sporting breeds are most commonly affected by blastomycosis. Signs may include dyspnea, tachypnea, fever, lethargy, weight loss, skin abscesses, uveitis, and pulmonary nodules.10


…TO YOUR PATIENTS

Key pearls to put into practice:

1

NSI can result in zoonotic transmission or injection of substances (eg, vaccines, antimicrobials, chemotherapeutics, euthanasia solution).

 

2

Performing fine-needle aspiration or necropsy on a dog with Blastomyces spp infection can result in human infection if there is a needlestick or sharps injury.

 

3

Staff should be educated on safe sharps handling and possible adverse health outcomes.1,2 All NSIs should be recorded, and staff should be trained in human first aid and blood-borne pathogen awareness.

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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Blue Buffalo CB June 2021

Research Note: Body Temperature Measurement in Guinea Pigs

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Body temperature is an important clinical indicator. In guinea pigs, the physical restraint required for taking a rectal temperature can cause stress and may induce hyperthermia. Less invasive methods for obtaining a temperature in this species have been examined; the present study assessed whether body temperatures taken in the axillary (AT) or inguinal (IT) areas were as accurate as rectal temperature (RT). Temperatures were measured in duplicate using a commercially available digital thermometer according to a standardized method over a short (<3 minute) period. AT and IT were consistently significantly lower than RT by 0.58ºF (0.32ºC) and 1.31ºF (0.73ºC), respectively. RT was not unduly stressful, and no patients were injured. Given these findings, the authors concluded that rectal temperature should remain the gold standard for temperature measurement in guinea pigs.

Source

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

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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.


Research Note: Mineral Content in Cat Foods

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Studies suggest that high dietary phosphorus (P) and low calcium:phosphorus (Ca:P) ratios may contribute to the development of chronic kidney disease (CKD) in cats. Although feline dietary minimums exist for P, Ca, and magnesium (Mg), there are no available maximums. This study evaluated P, Ca, and Mg in 82 commercial, nonprescription cat foods and examined discrepancies between reported and analyzed quantities. Of the foods tested, 81 had an Association of American Feed Control Officials nutritional adequacy statement on the label. However, 33% contained phosphorus levels >3.6 g/1000 kcal ME, which is in the range of levels experimentally shown to cause renal dysfunction in healthy cats. Nine percent of the foods had P levels >4.8 g/1000 kcal ME, which has been shown to cause rapid renal decline in adult cats when most P was provided by inorganic P sources. Sixteen percent of the foods had low Ca:P ratios. These results suggest pet food regulatory reform 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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Imoxi CB June 2021

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Apoquel CB June 2021

Gastric Dilation & GI Obstruction in Rabbits

David Eshar, DVM, DABVP (ECM), DECZM (SM & ZHM), Kansas State University

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Gastric Dilation & GI Obstruction in Rabbits

In the literature

Brezina T, Fehr M, Neumüller M, Thöle M. Acid-base-balance status and blood gas analysis in rabbits with gastric stasis and gastric dilation. J Exotic Pet Med. 2020;32:18-26.


FROM THE PAGE …

GI stasis is one the most common health issues in pet rabbits and often occurs secondary to an underlying medical issue.1 With the exception of physiologic ileus (eg, from a low-fiber diet), common primary problems that occur with GI stasis include gastric dilation and GI obstruction, typically of either the pylorus or duodenum. In most cases, a small ingested hair pellet is the cause of the intestinal obstruction.2 Stomach outflow obstruction can lead to caudal vena cava compression, cranial displacement of the diaphragm, activation of the sympathetic nervous system, severe pain, and reduced respiratory lung volume and heart preload. If the stomach outflow obstruction is left untreated, the pathophysiologic changes continue to worsen, leading to debilitating pain, hypovolemia, hypotension, hypothermia, disseminated intravascular coagulation, and acidosis.3-9

In addition to diagnostic imaging, clinical pathology (ie, CBC, serum chemistry profile, blood gas analysis) is important for determining a patient’s health status.3-11 For example, hyponatremia is considered a negative prognostic factor,4 and severe hyperglycemia can occur due to severe pain and stress, which can affect treatment and management decisions.5 As in other species with severe GI disturbances, blood gas analysis and acid-base status can be useful in determining appropriate treatment.

In this study of pet rabbits with gastric dilation and suspected obstruction, the authors evaluated acid-base status, electrolytes, and blood gas values, as well as how both time of presentation and therapy influenced these parameters. Prospective data from 30 rabbits were included. The resulting data suggest that acid-base balance disturbances due to gastric dilation can worsen over time without treatment. Specifically, partial pressure of carbon dioxide, partial pressure of bicarbonate, and base excess were significantly lower in rabbits presented 12 hours after the owner first noticed signs of illness as compared with rabbits presented within 6 hours. These findings strongly suggest the need for immediate veterinary care in rabbits showing reduced activity, dysphagia, and changes in fecal output.

Right lateral radiograph of a 1-year-old, intact male Holland lop rabbit presented with a history of reduced activity, anorexia, and no fecal output since the previous day. Blood glucose was 328 mg/dL (reference range, 110-160 mg/dL). The stomach appears distended and fluid-filled with a gas cap, and an abnormal gas pattern can be seen in the small intestines. The combination of history, clinical signs, physical examination, hyperglycemia, and radiographic findings is highly suggestive of intestinal obstruction.
Right lateral radiograph of a 1-year-old, intact male Holland lop rabbit presented with a history of reduced activity, anorexia, and no fecal output since the previous day. Blood glucose was 328 mg/dL (reference range, 110-160 mg/dL). The stomach appears distended and fluid-filled with a gas cap, and an abnormal gas pattern can be seen in the small intestines. The combination of history, clinical signs, physical examination, hyperglycemia, and radiographic findings is highly suggestive of intestinal obstruction.

FIGURE Right lateral radiograph of a 1-year-old, intact male Holland lop rabbit presented with a history of reduced activity, anorexia, and no fecal output since the previous day. Blood glucose was 328 mg/dL (reference range, 110-160 mg/dL). The stomach appears distended and fluid-filled with a gas cap, and an abnormal gas pattern can be seen in the small intestines. The combination of history, clinical signs, physical examination, hyperglycemia, and radiographic findings is highly suggestive of intestinal obstruction.

FIGURE Right lateral radiograph of a 1-year-old, intact male Holland lop rabbit presented with a history of reduced activity, anorexia, and no fecal output since the previous day. Blood glucose was 328 mg/dL (reference range, 110-160 mg/dL). The stomach appears distended and fluid-filled with a gas cap, and an abnormal gas pattern can be seen in the small intestines. The combination of history, clinical signs, physical examination, hyperglycemia, and radiographic findings is highly suggestive of intestinal obstruction.


…TO YOUR PATIENTS

Key pearls to put into practice:

1

Survey radiography—including ventrodorsal, dorsoventral, and lateral views—is important in the initial screening and diagnosis of any rabbit showing GI or nonspecific clinical signs.11

 

2

Elevated blood glucose can indicate severe pain and help in the evaluation of efficacy of provided analgesics.5

 

3

Rectal temperature should always be obtained during physical examination of rabbits. Decreased rectal temperature at presentation has been shown to be a poor prognostic factor in rabbits with signs of GI dysfunction, particularly those with a temperature ≤97.9°F (36.6°C).7

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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Osurnia CB June 2021

Outcomes of Dogs with Splenic Mass Rupture

Timothy M. Fan, DVM, PhD, DACVIM (Oncology, Internal Medicine), University of Illinois at Urbana–Champaign

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Outcomes of Dogs with Splenic Mass Rupture

In the Literature

Stewart SD, Ehrhart EJ, Davies R, Khanna C. Prospective observational study of dogs with splenic mass rupture suggests potentially lower risk of malignancy and more favourable perioperative outcomes. Vet Comp Oncol. 2020;18(4):811-817.


FROM THE PAGE…

The spleen is an accessory organ responsible for physiologic functions that include extramedullary hematopoiesis and immune activities.1,2 Because the spleen is highly cellular and vascular in nature, it can be predisposed to anatomic anomalies, including the development of proliferative mass effects. Splenic masses can remain physically undetectable and clinically inconsequential in some patients; however, in a subset of affected dogs, rupture of an occult splenic mass can manifest as a spontaneous and life-threatening hemoabdomen.

The underlying pathology responsible for a ruptured splenic mass can be benign or malignant and significantly influences emergent treatment decisions by pet owners and long-term survival outcomes of affected dogs. Benign causes of splenic mass can include nodular lymphoid hyperplasia, focal extramedullary hematopoiesis, and hematomas. Malignant causes of splenic mass include hemangiosarcoma (HSA), other aggressive sarcomas (eg, histiocytic, undifferentiated), lymphoma, mast cell tumor, and metastatic solid tumors.3,4

HSA is a malignant neoplasm that originates from either vascular endothelium or hemangioblast lineage. The spleen remains the most common anatomic site of primary HSA development and has been reported to be the most common cause of spontaneous hemoabdomen associated with splenic mass rupture.5-7 However, these studies have been retrospective and are prone to bias that can influence reported results.8 Although splenic HSA is commonly considered a primary differential in dogs presented with a splenic mass and hemoabdomen, this assumed diagnosis can negatively influence owner decisions to pursue potentially life-saving interventions. There is significant justification for improving presurgical accuracy in the identification of dogs actually afflicted with HSA as the underlying pathology of hemoabdomen.9 In addition, prospective studies less prone to bias are needed to help form the foundational knowledge base used to guide owner decisions when the likely outcome of dogs with splenic mass and hemoabdomen is prognosticated.

This report* describes the findings derived from a prospective, observational study of 40 dogs with splenic mass rupture and spontaneous hemoabdomen presented for emergent care. Of these 40 dogs, 15 had benign masses and 25 had malignant masses. Twenty-four of the malignant splenic masses were confirmed to be HSA and, therefore, accounted for the majority (60%) of pathologies. Of 9 dogs with hepatic nodules identified via ultrasound, surgical biopsy or resection of the liver nodules confirmed metastatic HSA lesions in only 3 dogs (33%). Immediate surgical outcomes were favorable, with 95% of dogs surviving to discharge. Collectively, although 60% of splenic masses were HSA, this percentage trends lower than what has been reported in previous retrospective studies (63.3%-70.4%)5,6 and may suggest a more favorable outcome in dogs with splenic tumor rupture that could guide owner’s decision-making during emergent situations.

Ultrasound image of a splenic mass with a mixed echogenic pattern consistent with blended heterogeneous tumor and fluid-filled (blood) cavities in the splenic parenchyma&nbsp;
Ultrasound image of a splenic mass with a mixed echogenic pattern consistent with blended heterogeneous tumor and fluid-filled (blood) cavities in the splenic parenchyma&nbsp;

FIGURE 1 Ultrasound image of a splenic mass with a mixed echogenic pattern consistent with blended heterogeneous tumor and fluid-filled (blood) cavities in the splenic parenchyma 

FIGURE 1 Ultrasound image of a splenic mass with a mixed echogenic pattern consistent with blended heterogeneous tumor and fluid-filled (blood) cavities in the splenic parenchyma 

Surgically resected spleen and associated mass effects involving both the head and tail of the spleen—histologically confirmed to be hemangiosarcoma
Surgically resected spleen and associated mass effects involving both the head and tail of the spleen—histologically confirmed to be hemangiosarcoma

FIGURE 2 Surgically resected spleen and associated mass effects involving both the head and tail of the spleen—histologically confirmed to be hemangiosarcoma

FIGURE 2 Surgically resected spleen and associated mass effects involving both the head and tail of the spleen—histologically confirmed to be hemangiosarcoma

*This study was funded by Ethos Discovery.

…TO YOUR PATIENTS

Key pearls to put into practice:

1

Intraoperative and postoperative survival of dogs presented with splenic mass and associated hemoabdomen is high (≈95%) when appropriate and timely interventions are instituted.

2

Ultrasonographic identification of liver nodules in dogs presented for splenic mass and hemoabdomen should not be assumed to represent metastatic disease.

 

3

HSA should be considered the primary differential for splenic mass associated with hemoabdomen, but there is a significant percentage (≈40%) of dogs that may be cured if timely life-saving therapies (ie, surgical intervention with hemodynamic support) are instituted.

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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Nexgard CB June 2021

Effect of Dental Chews on Canine Plaque Microbiota

Heidi B. Lobprise, DVM, DAVDC, Main Street Veterinary Hospital & Dental Clinic, Flower Mound, Texas

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Effect of Dental Chews on Canine Plaque Microbiota

In the Literature

Ruparell A, Warren M, Staunton R, et al. Effect of feeding a daily oral care chew on the composition of plaque microbiota in dogs. Res Vet Sci. 2020;132:133-141.


FROM THE PAGE …

Although bacteria are implicated in the initiation of periodontal disease in dogs, the specific mechanism is unknown. Many types of bacteria are found in the oral cavity, and changes in the microbial community can disturb the equilibrium of the oral ecosystem, allowing disease to begin or intensify. Better methods of identifying bacterial species, including classification of bacteria genera into those generally associated with health (ie, health-associated taxa) and those associated with disease (ie, disease-associated taxa), have improved the understanding of these alterations. This triple crossover study* evaluated the influence of an oral care chew on the composition of microbiota of the canine oral cavity.

Supragingival plaque was collected from 12 beagles before the study (pretest phase), at which time a complete descale and polish was performed. During the 14-day pretest phase, the teeth were brushed daily with water. On day 1 of the test phase, another supragingival plaque sample was taken and another complete descale and polish was performed. Dogs were fed a commercially available wet and dry diet mix either alone or with an oral care chew. Plaque was sampled again after 28 days.

Descaling, polishing, and brushing appeared to effectively change the microbiota profiles toward a healthy composition prior to the beginning of day 1 of the test phase. The most abundant phylum at the start of the pretest phase was disease-associated Firmicutes, whereas health-associated Bacteroides was the most abundant phylum at the beginning of the test phase. Proteobacteria was the most abundant phylum for both groups (chew and nonchew) at the end of the study.

Of those that received chews, 6 dogs with health-associated taxa and 3 dogs with disease-associated taxa had increased bacteria. Of those that did not receive chews, 1 dog with health-associated taxa and 8 dogs with disease-associated taxa had increased bacteria. This study may not have been long enough to generate significant differences between the groups.

*This study was funded by Mars Petcare.

… TO YOUR PATIENTS

Key pearls to put into practice:

1

Periodontal disease in dogs is greatly influenced by bacteria in the mouth but with minimal antibiotic response.

2

In uncomplicated cases, oral bacteria as a component of plaque and calculus can be effectively managed with complete dental cleaning (descale and polish) and effective home care.

 

3

Any level of home care (eg, chews that decrease plaque and tartar, chews that can impact the microbiota of the oral cavity) can play an important role in the complete dental care of a dog.

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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Nestle CB June 2021

Radiographic Appearance of Benign Versus Malignant-Associated Bone Infarcts in Dogs

Stephen C. Jones, MVB, MS, DACVS-SA, The Ohio State University

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Radiographic Appearance of Benign Versus Malignant-Associated Bone Infarcts in Dogs

In the Literature

Jones SA, Gilmour LJ, Ruoff CM, Pool RR. Radiographic features of histologically benign bone infarcts and bone infarcts associated with neoplasia in dogs. J Am Vet Med Assoc. 2020;256(12):1352-1358.


FROM THE PAGE …

A bone infarct is an area of osteonecrosis that develops following an ischemic event. Bone infarcts can be of benign or malignant origins and have been reported to occur secondary to previous surgery (eg, total hip replacement) or bone neoplasia (eg, osteosarcoma).1-7 The radiographic appearance of malignant-associated bone infarcts has been described but benign infarcts have not.

This retrospective study aimed to assess radiography in discerning benign versus malignant-associated bone infarcts. Two board-certified radiologists were blinded to case signalment and ultimate histologic diagnosis and asked to assess radiographs of bone infarctions, classifying them as likely benign, likely malignant associated, or undistinguishable in nature.

Of the 49 included cases, 33 had a histologic diagnosis of benign infarct and 16 had a malignant-associated infarct. Only 48% of the benign infarcts and 38% of the malignant-associated infarcts were correctly identified by both radiologists. Patterns of both the periosteal response and the medullary lysis were the only radiographic features significantly associated with the histologic diagnosis. Despite this finding, there was substantial crossover, with a high percentage of dogs in both histologic groups having an aggressive periosteal response and an aggressive medullary lysis pattern. 

Overall, significant overlap was observed in the radiographic appearance of benign and malignant-associated infarcts, suggesting that radiographic assessment is not very useful in distinguishing the histologic nature of bone infarcts. These results underpin the need for additional diagnostics for bony lesions detected on radiology, even those with a radiographic pattern typical of an aggressive process.

… TO YOUR PATIENTS

Key pearls to put into practice:

1

Bone infarcts in dogs can be either benign or malignant in nature and can have considerable variability in radiographic features. Furthermore, the radiographic features of benign and malignant-associated infarcts have many similarities, making radiography an unreliable diagnostic modality for identifying the nature of the infarct.

2

Given the overlap in radiographic signs, benign bone infarcts in dogs could easily be misclassified as a malignant process, for which limb amputation is often the recommended surgical intervention. This finding underscores the importance of performing additional diagnostic evaluations (eg, bone biopsy) in dogs with an aggressive radiographic appearance.

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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Phnotix CB June 2021

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PVD CB June 2021

Improving Incidence of Upper Respiratory Infections in Shelter Kittens

Lisa L. Powell, DVM, DACVECC, BluePearl Veterinary Partners, Eden Prairie, Minnesota; Critical Consults, Pittsburgh, Pennsylvania

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Improving Incidence of Upper Respiratory Infections in Shelter Kittens

In the Literature

Jaynes RA, Thompson MC, Kennedy MA. Effect of ultraviolet germicidal irradiation of the air on the incidence of upper respiratory tract infections in kittens in a nursery. J Am Vet Med Assoc. 2020;257(9):929-932.


FROM THE PAGE…

Airborne pathogens that cause respiratory infections can contribute to significant illness in kittens housed in animal shelters. These pathogens, including feline herpesvirus-1, feline calicivirus, Bordetella bronchiseptica, Chlamydia felis, and Mycoplasma spp, can persist on surfaces and lead to fomite transmission. Intensive disinfection can help decrease the persistence of these pathogens and other contagions in a shelter environment. Ultraviolet (UV) germicidal irradiation has been found to effectively disinfect surfaces, air, and water1 and to decrease the spread of respiratory infections in humans when added to heating, ventilation, and air-conditioning (HVAC) systems.2-5

This study compared the incidence of upper respiratory infections (URIs) in a kitten nursery setting before and after a UV germicidal irradiation system was installed in an HVAC system. Incidence of URIs (ie, URIs per 100 kittens housed) prior to installation of the UV irradiation system was compared with the incidence of URIs after the UV irradiation system was in place 2 years later. Records were reviewed for the number of kittens housed in the nursery, as well as the number of kittens diagnosed with URI based on clinical signs. Intensive disinfection and personal protective equipment (PPE) protocols for staff remained as standard operating procedures.

Evaluation of incidence of infection revealed a significant decrease in URIs diagnosed in kittens after the UV germicidal irradiation system was in use. Incidence of URIs was 12.4 prior to and 1.6 after (2 years later) installation of the UV system—an 87.1% decrease in development of URIs.


…TO YOUR PATIENTS

Key pearls to put into practice:

1

In a shelter environment where URIs are common and easily transmitted, addition of a UV germicidal irradiation system could significantly decrease incidence of infections caused by common respiratory viruses.

2

Strict disinfection protocols and consideration for UV germicidal irradiation in shelter environments are also important.

3

UV irradiation in other veterinary environments (eg, general clinics, intensive care units, research facilities, rescue/large shelter organizations) could also be considered. It is unknown whether other types of viruses, bacteria, or fungal organisms may be susceptible to UV irradiation; thus, further studies are warranted.

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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Elura CB June 2021

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Redonyl CB June 2021

Top 5 Fine-Needle Biopsy Sample Collection & Handling Errors

Isabelle Soga, DVM candidate, Kansas State University

Lisa M. Pohlman, DVM, MS, DACVP, Kansas State University

Clinical Pathology

|Peer Reviewed

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Top 5 Fine-Needle Biopsy Sample Collection & Handling Errors

FIGURE 1 A soft mass on the tail of a 14-year-old dachshund. Fine-needle biopsy is performed using the needle-only nonaspiration method. The mass is stabilized with the clinician’s free hand, and the collection needle is inserted into the tissue and redirected multiple times before exiting the tissue. Following collection, the collection-needle should be attached to an air-filled syringe so the sample can be expelled onto a clean glass slide. A squash preparation can then be prepared.

Fine-needle biopsy is an effective diagnostic tool that allows for the retrieval of samples without anesthesia (and often without analgesia), thereby significantly reducing cost and avoiding potential adverse effects associated with more invasive procedures. In-clinic cytology examination or submission to a reference laboratory with a rapid turnaround time can provide cursory information. In cases in which a definitive diagnosis is not achieved, cytology can typically help direct additional testing. One study found 89% sensitivity and 100% specificity for cytologic detection of neoplasia in cutaneous and subcutaneous lesions.1 Sample quality is a key factor in ensuring diagnostic yield, and proper technique in sample collection and handling can help avoid nondiagnostic samples.2

Following are, in the authors’ opinion, the 5 most common fine-needle biopsy collection and handling errors that result in nondiagnostic samples, along with corrective actions.

1

Improper Collection Technique

The 2 fine-needle biopsy collection techniques are aspiration and nonaspiration. The nonaspiration technique (also called the capillary, stab, or woodpecker technique) is the preferred method of collection because it reduces the amount of blood contamination and can produce samples of excellent diagnostic quality.3,4

Common errors with the nonaspiration technique include lack of redirection, which can result in a nonrepresentative sample, and timid collection, which can result in a poorly cellular sample. Occasionally (ie, when lesions are poorly exfoliative), the nonaspiration technique does not yield an adequately cellular sample for cytologic interpretation. Therefore, an additional (less common in the authors’ opinion) error is not recognizing when use of the nonaspiration technique alone does not suffice and, consequently, when additional sampling via the aspiration technique is required.

The nonaspiration technique can be performed using a needle only (Figure 1) or a needle attached to an air-filled syringe (Figure 2).3 For cutaneous and subcutaneous masses or peripheral lymph nodes, the tissue to be sampled should be stabilized with the clinician’s free hand, and the needle should be inserted into the tissue and redirected (ie, moved back and forth) several times without exiting the mass.5 The sample can then be expelled onto a slide via an air-filled syringe. The goal is to gather a representative population of cells.3-5

A soft mass on the tail of a 14-year-old dachshund. Fine-needle biopsy is performed using the nonaspiration method with an air-filled syringe attached to the needle. The mass is stabilized with the clinician’s free hand, and the collection needle, with an air-filled syringe attached, is inserted into the tissue and redirected multiple times before exiting the tissue. Following collection, the sample is immediately expelled onto a clean glass slide, and a squash preparation can be prepared.
A soft mass on the tail of a 14-year-old dachshund. Fine-needle biopsy is performed using the nonaspiration method with an air-filled syringe attached to the needle. The mass is stabilized with the clinician’s free hand, and the collection needle, with an air-filled syringe attached, is inserted into the tissue and redirected multiple times before exiting the tissue. Following collection, the sample is immediately expelled onto a clean glass slide, and a squash preparation can be prepared.

FIGURE 2 A soft mass on the tail of a 14-year-old dachshund. Fine-needle biopsy is performed using the nonaspiration method with an air-filled syringe attached to the needle. The mass is stabilized with the clinician’s free hand, and the collection needle, with an air-filled syringe attached, is inserted into the tissue and redirected multiple times before exiting the tissue. Following collection, the sample is immediately expelled onto a clean glass slide, and a squash preparation can be prepared.

FIGURE 2 A soft mass on the tail of a 14-year-old dachshund. Fine-needle biopsy is performed using the nonaspiration method with an air-filled syringe attached to the needle. The mass is stabilized with the clinician’s free hand, and the collection needle, with an air-filled syringe attached, is inserted into the tissue and redirected multiple times before exiting the tissue. Following collection, the sample is immediately expelled onto a clean glass slide, and a squash preparation can be prepared.

Errors with the aspiration technique are common and include prolonged aspiration or repeated pulses of negative pressure, both of which can result in significant blood contamination and an overly diluted sample3,5; failure to release negative pressure and stop aspiration before the needle is removed from the tissue, which can result in the sample entering the barrel of the syringe and an inability to easily retrieve it; and timid collection, which can result in a poorly cellular sample.3

For the aspiration technique, the needle should be attached to an empty syringe and inserted into the mass. Negative pressure should then be applied by withdrawing the plunger once (Figure 3) and redirecting the needle while negative pressure is maintained and without the needle exiting the mass. Before the needle is removed, the negative pressure should be released, as maintaining pressure while the needle exits the mass can result in the sample entering the barrel of the syringe. After the needle is removed from the mass, it must be removed from the syringe. Air is added to the syringe, then the needle is reattached so the sample can then be expelled on a clean glass slide.3

Highly exfoliative and vascular tissues (eg, lymph nodes, round and epithelial cell neoplasms) are typically successfully sampled using the nonaspiration technique6; thus, the nonaspiration technique should be attempted first. The aspiration technique should only be used if cells are not exfoliating with the nonaspiration technique. In the authors’ opinion, spindle cell lesions are more likely to be poorly exfoliative with the nonaspiration technique and may require the aspiration technique to obtain an adequate sample. 

Fine-needle biopsy using the aspiration technique on a firm, cutaneous mass on the right lateral forelimb (just distal to the elbow) of a border collie crossbreed. The needle, which is attached to an empty syringe, is inserted in the lesion. Negative pressure is applied by pulling the plunger back once (arrow). Pressure is maintained during needle-redirection to obtain a sample.
Fine-needle biopsy using the aspiration technique on a firm, cutaneous mass on the right lateral forelimb (just distal to the elbow) of a border collie crossbreed. The needle, which is attached to an empty syringe, is inserted in the lesion. Negative pressure is applied by pulling the plunger back once (arrow). Pressure is maintained during needle-redirection to obtain a sample.

FIGURE 3 Fine-needle biopsy using the aspiration technique on a firm, cutaneous mass on the right lateral forelimb (just distal to the elbow) of a border collie crossbreed. The needle, which is attached to an empty syringe, is inserted in the lesion. Negative pressure is applied by pulling the plunger back once (arrow). Pressure is maintained during needle-redirection to obtain a sample.

FIGURE 3 Fine-needle biopsy using the aspiration technique on a firm, cutaneous mass on the right lateral forelimb (just distal to the elbow) of a border collie crossbreed. The needle, which is attached to an empty syringe, is inserted in the lesion. Negative pressure is applied by pulling the plunger back once (arrow). Pressure is maintained during needle-redirection to obtain a sample.

2

Incorrect Needle and/or Syringe Size

In general, 22- to 25-gauge needles can be used for fine-needle biopsy collection, but needle size should be determined based on firmness of the tissue to be aspirated.3 Softer tissue requires a needle gauge on the higher side of the range (eg, 23-25–gauge). Using needles that are <25-gauge increases the risk for breakage and distortion of cells.7 Firmer tissue requires a larger needle size; hence, a 22-gauge needle is ideal. Needles >22-gauge often result in tissue cores, preventing creation of a proper monolayer for analysis. Larger needles also increase the risk for blood contamination.3

For the nonaspiration technique, the size of the syringe is not critical, as it is simply used to rapidly expel the sample on the slide after collection.3 However, for the aspiration technique, the size of the syringe (much like needle size) should be selected based on tissue consistency. A smaller syringe size (3-mL) is sufficient for softer tissue (eg, lymph nodes) because minimal negative pressure is needed for sample collection. Firmer tissue requires increased negative pressure to obtain a sufficient number of cells.3

If there is uncertainty, a 12-mL syringe3 with a 23-gauge needle is generally safe.

3

Localization Error

Successful sample collection depends on the accuracy of the needle-tip delivery. Common localization errors include a geographic miss (ie, the needle misses the lesion entirely and instead samples a nonrepresentative area [eg, subcutaneous or perinodal fat])3; shallow passes of the collection needle (ie, the needle hits the lesion, but just barely), which can result in a poorly cellular sample3; and inadequate or insufficient needle redirection—the likelihood of a nondiagnostic sample increases with <4 redirections.6

4

Inappropriate Slide-Preparation Technique

The slide-over-slide (also called squash prep) method is the preferred smear preparation for fine-needle biopsy samples.3 The goal is to achieve a thin film of cells spread out in a single layer (ie, the monolayer) without damaging the cells. Contrary to its name, this procedure requires minimal to no pressure, as overly aggressive pressing of the slides can result in cell rupture (Figure 4).3 The sample should first be expelled onto a clean glass slide toward one end, leaving room for the sample to be spread; this is referred to as the sample slide. A spreader slide is then gently placed either parallel to or perpendicular on top of the sample slide with no downward digital pressure, allowing just the weight of the slide to “squash” the preparation. The top slide should be pulled horizontally to glide over the bottom slide until the 2 slides are separate. A common error is to pull the 2 slides vertically apart; the resulting suction can rupture the cells.3

Slides that are being used for cytologic preparation (including sample and spreader slides) should never be heat- or formalin-fixed. After the squash preparation is made, the smears should be air-dried via rapid waving of the slides or by placing the slides in front of a fan.3,5 After air-drying, the slides can either be shipped unstained to a reference laboratory for assessment by a clinical pathologist or stained for in-clinic viewing.

Nondiagnostic sample from a fine-needle biopsy of a lymph node. Almost all cells on the smear are ruptured. One nucleated cell (a neutrophil; circle) is intact. Nuclei with no associated cytoplasm (ie, naked nuclei; solid arrows) can be seen. Streaming nuclear material (dashed arrows) and scattered RBCs (curved arrows) can be seen. Large, clear spaces (asterisks) represent lipid (likely subcutaneous or perinodal fat in this case), which is a common finding on cytology samples. Modified Wright’s stain, 600x magnification
Nondiagnostic sample from a fine-needle biopsy of a lymph node. Almost all cells on the smear are ruptured. One nucleated cell (a neutrophil; circle) is intact. Nuclei with no associated cytoplasm (ie, naked nuclei; solid arrows) can be seen. Streaming nuclear material (dashed arrows) and scattered RBCs (curved arrows) can be seen. Large, clear spaces (asterisks) represent lipid (likely subcutaneous or perinodal fat in this case), which is a common finding on cytology samples. Modified Wright’s stain, 600x magnification

FIGURE 4 Nondiagnostic sample from a fine-needle biopsy of a lymph node. Almost all cells on the smear are ruptured. One nucleated cell (a neutrophil; circle) is intact. Nuclei with no associated cytoplasm (ie, naked nuclei; solid arrows) can be seen. Streaming nuclear material (dashed arrows) and scattered RBCs (curved arrows) can be seen. Large, clear spaces (asterisks) represent lipid (likely subcutaneous or perinodal fat in this case), which is a common finding on cytology samples. Modified Wright’s stain, 600x magnification

FIGURE 4 Nondiagnostic sample from a fine-needle biopsy of a lymph node. Almost all cells on the smear are ruptured. One nucleated cell (a neutrophil; circle) is intact. Nuclei with no associated cytoplasm (ie, naked nuclei; solid arrows) can be seen. Streaming nuclear material (dashed arrows) and scattered RBCs (curved arrows) can be seen. Large, clear spaces (asterisks) represent lipid (likely subcutaneous or perinodal fat in this case), which is a common finding on cytology samples. Modified Wright’s stain, 600x magnification

5

Inappropriate Shipping Procedure

Properly protecting slides during transportation/shipping is a major concern.3,8 Cardboard and soft-plastic casings require additional protection (eg, bubble wrap), as slides are easily broken (Figure 5).3 Containers made of hard plastic or polystyrene foam are ideal (Figure 6). Unstained slides should be packaged separately from formalin-containing samples. Even if the slides are individually wrapped, the formalin fumes can penetrate packaging and deleteriously affect the cytology preparations, resulting in a nondiagnostic sample.3,5

Relevant history and clinical findings are essential to provide context for clinical pathologists. Therefore, it is important to include location and macroscopic description of the lesion, method of sample collection, clearly labeled slides, time of collection, and concise clinical history (including signalment) with every shipped sample.6 Submitting several slides (rather than one) increases the likelihood of a productive report.

Slides broken during shipment due to inadequate protective packaging&nbsp;
Slides broken during shipment due to inadequate protective packaging&nbsp;

FIGURE 5 Slides broken during shipment due to inadequate protective packaging 

FIGURE 5 Slides broken during shipment due to inadequate protective packaging 

Slide holders that can be used for shipping slides. The hard-plastic box and polystyrene foam container (solid arrows) are protective enough to ship slides without additional packaging. The cardboard and soft-plastic casing (dashed arrows) need additional protection during shipping.
Slide holders that can be used for shipping slides. The hard-plastic box and polystyrene foam container (solid arrows) are protective enough to ship slides without additional packaging. The cardboard and soft-plastic casing (dashed arrows) need additional protection during shipping.

FIGURE 6 Slide holders that can be used for shipping slides. The hard-plastic box and polystyrene foam container (solid arrows) are protective enough to ship slides without additional packaging. The cardboard and soft-plastic casing (dashed arrows) need additional protection during shipping.

FIGURE 6 Slide holders that can be used for shipping slides. The hard-plastic box and polystyrene foam container (solid arrows) are protective enough to ship slides without additional packaging. The cardboard and soft-plastic casing (dashed arrows) need additional protection during shipping.

Conclusion

Collection and preparation of quality fine-needle biopsy samples is a skill that is honed through experience and refinement of technique. Collection method and needle and syringe size should be determined based on tissue characteristics. In the authors’ opinion, the nonaspiration technique should be attempted first because it is the preferred method to obtain a sample of excellent diagnostic quality.3,4 If the nonaspiration technique fails to exfoliate cells, the aspiration technique may be successful, but it is also more likely to be contaminated with peripheral blood. Squash preparations should be prepared with a view to minimize cell damage and maximize production of a monolayer of well-spread, intact cells. Labeled, air-dried smears can then be stained for in-clinic viewing or packed appropriately and shipped (along with relevant history and lesion description) to a reference laboratory for evaluation by a clinical pathologist.

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.

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iM3 CB June 2021
Clinical Notes: Canine Transitional Cell Carcinoma: What’s New?

Clinical Notes: Canine Transitional Cell Carcinoma: What’s New?

Matthew Breen, PhD, CBiol, FRSB

Claire Wiley, VMD, DACVIM (SAIM)

Oncology

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Clinical Notes: Canine Transitional Cell Carcinoma: What’s New?
Sponsored by an Unrestricted Educational Grant from Nutramax Laboratories Veterinary Sciences, Inc.

KEY POINTS

  • A molecular approach is available to noninvasively aid in detecting patients suspected of having TCC/UC and breeds predisposed to TCC/UC, allowing the approach to management to be determined earlier.
  • Dog breed and environmental elements are predisposing factors for TCC/UC.
  • Biological phytochemical compounds that may support approaches to traditional multimodal management have been identified.
  • A bioavailable sulforaphane production supplement (Avmaquin™) has been shown to increase sulforaphane in the bloodstream of dogs.

Detection: Commercially Available Molecular Test

The most common cancer of the canine urinary tract is transitional cell carcinoma (TCC), also known as urothelial carcinoma (UC).1,2 It is estimated to represent 1% to 2% of all canine cancers,3 with increasing prevalence seen at university teaching hospitals.1 Risk factors for TCC/UC include obesity, female sex, and exposure to specific environmental agents such as herbicide-treated lawns.1,4,5 An elevated incidence has been observed in a number of dog breeds, including Scottish terriers, Shetland sheepdogs, West Highland white terriers, wire fox terriers, and beagles.1,3,6,7

TCC/UC is often identified following observation of lower urinary tract signs (eg, stranguria, pollakiuria, hematuria). These signs may also result from other more common bladder health issues such as UTI, polyps, prostatitis, and bladder stones.

Because bladder infections are a common reason for dogs to be presented with lower urinary tract signs, first-line management often involves antibiotic and/or anti-inflammatory medications, with recurrence of signs eventually creating concern for TCC/UC.1,3,6,8,9

Histopathology is the gold standard for detection of TCC/UC, but this approach requires invasive and costly procedures. The use of traditional, noninvasive options relies on cytologic identification of abnormal epithelial cells in urine specimens, which may be misleading and contribute to delayed detection.5,10,11 Once TCC/UC is diagnosed, management options vary and can include cyclooxygenase inhibitors, cytotoxic chemotherapy, radiation therapy, and surgery.5 Prognosis is generally guarded.2,12

Molecular studies of canine TCC/UC have identified the presence of a single base mutation in the canine BRAF gene, which has been detected in ≈85% of cases studied.13,14 The remarkably high prevalence of this mutation in patients with TCC/UC as compared with patients with other cancers15 has facilitated development of a commercially available molecular test with high sensitivity and specificity using a noninvasive (free-catch) urine sample.13 Further, using a technical approach that is not impacted by the presence of blood, protein, and bacteria in the urine enhances the utility of this approach to aid detection of TCC/UC for dogs with overt clinical signs.13,16 Earlier detection may increase the time for appropriate intervention, thus enhancing opportunities to potentially improve outcomes. Moreover, detection of low-level mutation, associated with preclinical cases of TCC/UC, provides opportunities for veterinarians to consider the most appropriate management, which could improve quality and duration of life of these patients.

The remarkably high prevalence of this mutation in patients with TCC/UC as compared with patients with other cancers has facilitated development of a commercially available molecular test with high sensitivity and specificity using a noninvasive (free-catch) urine sample.

In addition to earlier detection, it is critical to focus on measures that optimize canine urinary tract health, such as avoiding environmental risk factors, maintaining a healthy weight, and ensuring a healthy diet, including cruciferous vegetable supplementation.4,7,17 Studies of dietary supplements aimed at supporting management of human cancers, bladder included, suggest that sulforaphane, found in raw cruciferous vegetables, may provide added benefits to humans, with potential translation to canine patients.18-24

What Is Sulforaphane?

Cruciferous vegetables, most notably broccoli, contain crucial isothiocyanates, which produce a key compound: sulforaphane (SFN).25 It releases into the body upon breaking down from its precursor, the phytonutrient glucoraphanin. Although glucoraphanin occurs in all parts of the broccoli plant, it is concentrated in the seeds and sprouts.26 The introduction of the plant enzyme, myrosinase, from intracellular vesicles catalyzes the hydrolysis of glucoraphanin to SFN.26 This breakdown process initiates through damage to the plant (eg, chewing, chopping, cutting).

Mechanisms of Action

The primary mechanism through which SFN supports cellular health is by direct antioxidant effects or by indirectly inducing phase 2 detoxifying enzymes by upregulating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, thereby reducing oxidative stress.18,27 Nrf2 has been shown to support cells and tissue from various insults by increasing the expression of a number of these phase 2 enzyme genes.28 Phase 2 detoxification enzymes (eg, NQO1, glutathione reductase, glutathione-S-transferases) play an important role in detoxifying potential mutagenic toxicants. Under physiologic conditions, Nrf2 is primarily localized in a complex with Kelch-like ECH-associated protein 1 (Keap1). Keap1 is inactivated upon exposure to oxidative stress, which dislodges Nrf2 and allows Nrf2 to transfer into the nucleus to activate phase 2 enzyme genes.28 SFN is one of the most potent phytochemicals that can activate the Nrf2 pathway.26

Sulforaphane Research

SFN has been the subject of extensive research identifying major supportive pathways of cellular activity, leading to the initiation of numerous studies indicating its role in aiding cellular health in humans.23,29,30 SFN research in veterinary medicine is emerging, with further research warranted to identify clinical applications. When administered to healthy dogs in a study, a broccoli sprout supplement containing glucoraphanin and active myrosinase (the precursors to SFN) showed absorption in plasma and urine that remained detectable at 24 and 48 hours, respectively, postconsumption.31 Researchers also noted a decrease in activity of histone deacetylase, a chromatin-modifying enzyme that has been shown to have increased activity with certain mutagenic cells in the body, at 24 hours postadministration.31 A study of SFN supplementation in dogs with compromised lymphatic health was associated with significant changes in lymph node proteome.32 The proteins impacted by SFN involved immune health and oxidative stress responses. A study using canine cell lines demonstrated diminished cell invasion in the cells treated with SFN.18

SFN research in veterinary medicine is emerging, with further research warranted to identify clinical applications.

Studies of the pharmacodynamic and pharmacokinetic properties of an oral glucoraphanin and myrosinase supplement supporting sulforaphane production were performed in beagle dogs.33 Blood samples of 4 dogs administered a tablet containing a proprietary blend of glucoraphanin and active myrosinase (Avmaquin™) orally once a day for a 3-day period revealed induced phase 2 enzyme gene expression at all time points after administration and increases in plasma SFN levels.33 Furthermore, administration of glucoraphanin in a fasted state has been shown to significantly increase SFN plasma levels as compared with administration with food.34 Results from this study showed higher total peak plasma SFN than a recently published study.31

Supplemental Options

Consumption of specific levels of SFN from routinely harvested broccoli or sprouts alone can be difficult to achieve due to variations in environment, plant genotype, and harvesting methods. In addition, because heat can damage SFN hydrolysis, variation in cooking methods can lead to inconsistencies in amounts.26,35 Sprouts can contain ≥100 times more phytonutrients than mature plants,26,36 but broccoli is particularly sensitive to metals in contaminated soil, which can affect plant development.37

Glucoraphanin, the precursor of SFN, is a comparatively stable molecule that can be converted to SFN by exposure to myrosinase, making it a good candidate for dietary supplementation. Although glucoraphanin occurs in all parts of broccoli plants, it is most abundant in the sprouts and seeds.26 Seed extraction of glucoraphanin and myrosinase ensure a stabilized, consistent source of SFN as compared with cruciferous vegetable supplementation.

Future Directions

With a commercially available detection method for dogs with TCC/UC issues, veterinarians may be able to intervene more appropriately and target management of patients. SFN has been extensively studied for its mechanisms of action and shown to be of benefit in various human studies. As SFN research continues to emerge in veterinary medicine, additional studies are warranted to assess potential benefits of SFN for clinical applications.

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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Pelvic Limb Lameness in a Cat

Kaitlin N. Bahlmann, DVM, Exclusively Cats Veterinary Hospital, Waterford, Michigan

Steven J. Bailey, DVM, DABVP (Feline), Exclusively Cats Veterinary Hospital, Waterford, Michigan

Orthopedics

|Peer Reviewed

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Pelvic Limb Lameness in a Cat

Zsa Zsa, an 18-month-old, 8-lb (3.6-kg) spayed domestic longhair cat, was presented for a 2-week history of left pelvic limb lameness and decreased activity levels. She was an indoor-only cat and was current on annual vaccinations, and her owners reported no known trauma.

Physical Examination

On physical examination, Zsa Zsa was bright, alert, and responsive. Vital parameters were within normal limits, except for an elevated heart rate (260 bpm). Oral examination revealed persistent deciduous teeth with coeruption of the permanent teeth, gingivitis, and calculus (Figure 1). Thoracic auscultation was unremarkable. Orthopedic examination revealed moderate left pelvic limb lameness. Pain and swelling were identified on palpation of the left stifle joint. Her BCS (5/9) and muscle condition score (3/3) were normal. The remainder of the clinical examination was unremarkable.

Clinician's Brief
Clinician's Brief
Persistent deciduous premolars in the right maxilla (A), left maxilla (B), right mandible (C), and left mandible (D). Coeruption of the deciduous and permanent maxillary canines, as well as marked gingivitis and calculus, particularly of the maxillary teeth, can be seen.
Persistent deciduous premolars in the right maxilla (A), left maxilla (B), right mandible (C), and left mandible (D). Coeruption of the deciduous and permanent maxillary canines, as well as marked gingivitis and calculus, particularly of the maxillary teeth, can be seen.

FIGURE 1 Persistent deciduous premolars in the right maxilla (A), left maxilla (B), right mandible (C), and left mandible (D). Coeruption of the deciduous and permanent maxillary canines, as well as marked gingivitis and calculus, particularly of the maxillary teeth, can be seen.

Persistent deciduous premolars in the right maxilla (A), left maxilla (B), right mandible (C), and left mandible (D). Coeruption of the deciduous and permanent maxillary canines, as well as marked gingivitis and calculus, particularly of the maxillary teeth, can be seen.
Persistent deciduous premolars in the right maxilla (A), left maxilla (B), right mandible (C), and left mandible (D). Coeruption of the deciduous and permanent maxillary canines, as well as marked gingivitis and calculus, particularly of the maxillary teeth, can be seen.

FIGURE 1 Persistent deciduous premolars in the right maxilla (A), left maxilla (B), right mandible (C), and left mandible (D). Coeruption of the deciduous and permanent maxillary canines, as well as marked gingivitis and calculus, particularly of the maxillary teeth, can be seen.

FIGURE 1 Persistent deciduous premolars in the right maxilla (A), left maxilla (B), right mandible (C), and left mandible (D). Coeruption of the deciduous and permanent maxillary canines, as well as marked gingivitis and calculus, particularly of the maxillary teeth, can be seen.

Diagnosis

Differential diagnoses for the patient’s stifle swelling, lameness, and pain included patellar luxation, atraumatic stress fracture of the patella, long bone fracture, soft-tissue or musculoskeletal injury (eg, cranial cruciate ligament injury), viral polyarthritis, and slipped capital femoral epiphysis. Inflammatory and neoplastic processes were considered less likely due to the patient’s age and absence of other clinical abnormalities. Patellar insufficiency fracture (ie, stress fracture) remained a likely differential due to the presence of persistent deciduous teeth and the possibility of osteogenic disease. Hypothyroidism was considered less likely due to the patient’s normal conformation and weight, as well as the absence of lethargy and anorexia.

The patient received buprenorphine (15 µg/kg IV) for analgesia, followed by an induction with alfaxalone (0.5 mg/kg IV) and general anesthesia with isoflurane to facilitate dental and orthopedic radiography. Dental radiographs revealed persistent deciduous teeth and impacted permanent teeth. Lateral and craniocaudal pelvic limb radiographs revealed a displaced left patellar fracture and a nondisplaced right patellar fracture (Figure 2).

Lateral radiographs of the left (A) and right (B) stifles show a complete, displaced left patellar fracture and a nondisplaced right patellar fracture, respectively.
Lateral radiographs of the left (A) and right (B) stifles show a complete, displaced left patellar fracture and a nondisplaced right patellar fracture, respectively.

FIGURE 2 Lateral radiographs of the left (A) and right (B) stifles show a complete, displaced left patellar fracture and a nondisplaced right patellar fracture, respectively.

Lateral radiographs of the left (A) and right (B) stifles show a complete, displaced left patellar fracture and a nondisplaced right patellar fracture, respectively.
Lateral radiographs of the left (A) and right (B) stifles show a complete, displaced left patellar fracture and a nondisplaced right patellar fracture, respectively.

FIGURE 2 Lateral radiographs of the left (A) and right (B) stifles show a complete, displaced left patellar fracture and a nondisplaced right patellar fracture, respectively.

FIGURE 2 Lateral radiographs of the left (A) and right (B) stifles show a complete, displaced left patellar fracture and a nondisplaced right patellar fracture, respectively.

DIAGNOSIS:

FELINE KNEES & TEETH SYNDROME

Treatment & Management

Zsa Zsa was discharged on an NSAID (robenacoxib, 2 mg/kg PO for a total of 3 days) for pain management. Exercise restriction over the next several weeks was advised. She was returned to the clinic several days later for dental cleaning and nerve blocks, after which all persistent deciduous teeth and impacted permanent teeth were extracted. Buprenorphine (15 ug/kg IV) was administered, followed by an induction with alfaxalone (0.5 mg/kg IV). General anesthesia was maintained with isoflurane. Postoperative dental radiographs confirmed that no retained teeth or roots remained.

The patient was managed postoperatively with buprenorphine (15 µg/kg IV every 8-12 hours), and a transdermal fentanyl patch (12.5 µg/hour) was placed on the left lateral thorax. She began to eat within a few hours after recovery; left pelvic limb lameness persisted. Gabapentin (50 mg PO every 12 hours) was prescribed for multimodal analgesia.

TREATMENT AT A GLANCE

  • A thorough orthopedic examination should be performed on all cats with persistent deciduous teeth.
  • Careful extraction of retained deciduous teeth or impacted adult teeth is critical.
  • Staged dental extractions may be warranted to avoid iatrogenic mandibular fracture.
  • Conservative management with exercise restriction and pain management is generally advised.
  • Surgical management of patellar fractures is typically discouraged due to the high rate of surgical failure.
  • Fractures of the acetabulum, tibia, and other bones can occur; serial radiography should be pursued depending on the progression of clinical signs.
  • Some cats may heal and adapt to fractures, whereas others may continue to have an altered, plantigrade gait.

Prognosis & Outcome

At the 3-week postoperative recheck, Zsa Zsa demonstrated decreased left pelvic limb lameness and reduced associated stifle swelling. Oral examination revealed appropriate healing of the gingiva. Continued exercise restriction over the following 6 weeks, with gradual return to previous activity, was recommended. At the 3-month recheck, she was ambulating normally and exhibited no residual lameness or stifle swelling. Repeat pelvic limb radiographs revealed unchanged bilateral patellar fractures. No additional therapy was recommended for the patellar fractures due to concerns of surgical failure.

Serial radiographs of the pelvic limbs were taken periodically to monitor progression of the patellar fractures. Comparative orthopedic radiographs (Figure 3) 2 and 8 years after initial presentation revealed persistence of patellar fractures, with fragmentation, progressive sclerosis, and osteophytosis of the left patella.

Clinician's Brief
Clinician's Brief
Radiographs of the patellar fractures taken 2 years (A, left stifle; B, right stifle) and 8 years (C, left stifle; D, right stifle) after initial presentation. Progressive fragmentation and osteophytosis of the left patella and displacement of the right patellar fragments can be seen.
Radiographs of the patellar fractures taken 2 years (A, left stifle; B, right stifle) and 8 years (C, left stifle; D, right stifle) after initial presentation. Progressive fragmentation and osteophytosis of the left patella and displacement of the right patellar fragments can be seen.

FIGURE 3 Radiographs of the patellar fractures taken 2 years (A, left stifle; B, right stifle) and 8 years (C, left stifle; D, right stifle) after initial presentation. Progressive fragmentation and osteophytosis of the left patella and displacement of the right patellar fragments can be seen.

Radiographs of the patellar fractures taken 2 years (A, left stifle; B, right stifle) and 8 years (C, left stifle; D, right stifle) after initial presentation. Progressive fragmentation and osteophytosis of the left patella and displacement of the right patellar fragments can be seen.
Radiographs of the patellar fractures taken 2 years (A, left stifle; B, right stifle) and 8 years (C, left stifle; D, right stifle) after initial presentation. Progressive fragmentation and osteophytosis of the left patella and displacement of the right patellar fragments can be seen.

FIGURE 3 Radiographs of the patellar fractures taken 2 years (A, left stifle; B, right stifle) and 8 years (C, left stifle; D, right stifle) after initial presentation. Progressive fragmentation and osteophytosis of the left patella and displacement of the right patellar fragments can be seen.

FIGURE 3 Radiographs of the patellar fractures taken 2 years (A, left stifle; B, right stifle) and 8 years (C, left stifle; D, right stifle) after initial presentation. Progressive fragmentation and osteophytosis of the left patella and displacement of the right patellar fragments can be seen.

Discussion

Feline knees and teeth syndrome is an association of nontraumatic patellar fractures and persistent deciduous teeth. This pathologic syndrome may include persistence of deciduous teeth, unerupted permanent teeth, and insufficiency fractures of the patella.1,2 Other fractures, including in the long bones and pelvis, and spinal abnormalities have also been reported.3,4 Pathologic fractures of the tibia and fibula can occur up to 10 years after diagnosis.2

Feline knees and teeth syndrome was first identified in the United States, but affected cats have since been identified in South America and the United Kingdom.2,5 This syndrome was believed to be a manifestation of osteogenesis imperfecta, but another mechanism is currently supported,6,7 as patellar fractures showing radiographic evidence of sclerosis and generalized osteosclerosis have been seen in both humans and cats.8 In humans, osteomyelitis of the jaw associated with osteopetrosis and dental pathology has been reported.8-10 In addition, fractures of the patella and other bones have been associated with generalized osteopetrosis.8-10 Patellar sclerosis has similarly been observed in some cats with knees and teeth syndrome.2,4,11

Feline knees and teeth syndrome is typically recognized in young cats, with male cats more frequently affected than female cats.2,12 The mean age of onset of pelvic limb lameness or radiographic diagnosis is 28 months (range, 4 months-8 years).5 Physical examination findings typically reveal persistent deciduous teeth, pelvic limb lameness, and swelling of the distal quadriceps muscle; concurrent paronychia has also been reported.2,4 Intraoral and whole-body orthopedic radiography, with particular attention given to the pelvic limbs, should be performed for evaluation. In some cases, lameness and quadricep swelling precede visible radiographic fractures.2,4

Failure of deciduous tooth exfoliation in cats is rare and most often the result of an altered eruption path of the permanent tooth (see Take-Home Messages). Persistence of deciduous cheek teeth was reported in 40 of 60 cats with patellar fractures in one case series.2 Another series of 191 cats with various fractures reported that 48% had dental anomalies possibly related to knees and teeth syndrome.4 Extraction of both the persistent deciduous teeth and the impacted adult teeth is key, as proliferative osteomyelitis, dentigerous cysts, and jaw deformation may develop when these teeth are left in situ (see Treatment at a Glance).2,11,13,14 A careful, meticulous technique is required to avoid mandibular fracture due to the space occupancy of the impacted teeth in the mandible/mandibular canal.2

Although surgical reduction of patellar fractures may seem like a good option, surgical failure was reported in 86% of cats with feline knees and teeth syndrome.15 Therefore, nonsurgical, conservative approaches should be considered.15 Fractures in these patients may heal or the patient may adapt to the fractures and function normally even without surgical management; other cats may develop a plantigrade gait.2 A study of cats with knees and teeth syndrome that developed humeral fractures lacked sufficient data to determine the long-term prognosis for surgical repair, suggesting that many of these fractures may heal with medical management alone.3

Most cats that sustain pathologic fractures of the patellae related to knees and teeth syndrome adapt with good return to function. Cats with persistent deciduous cheek teeth should be closely monitored because development of pathologic insufficiency fractures of the patellae and other bones may be anticipated. 

TAKE-HOME MESSAGES

  • Feline knees and teeth syndrome should be considered in cats that have spontaneous onset of pelvic limb lameness. 
  • Cats with persistent deciduous cheek teeth should be closely monitored, as pathologic (especially patellar) fractures can occur.
  • Cats with juvenile dental anomalies should be further evaluated with dental radiography. 
  • Extraction of any persistent deciduous teeth and unerupted adult teeth is recommended to prevent osteomyelitis, pain, and jaw deformation.
  • Acute lameness associated with nontraumatic patellar fracture often occurs at ≈2 years of age in cats with feline knees and teeth syndrome.
  • Pelvic limb lameness and distal quadricep swelling may precede patellar fractures.
  • Radiography of both pelvic limbs should be performed, even if lameness is only noted on one side.
  • Surgical reduction of patellar fractures is not recommended due to the high rate of failure.
  • Persistent lameness and an altered gait are possible long-term consequences of feline knees and teeth syndrome. 
  • Fractures of bones other than the patellae may occur and should be monitored.

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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Seresto CB June 2021

Differential Diagnosis: Neutrophilia

Marie A. Chartier, DVM, DACVIM, BluePearl Pet Hospital, Charlestown, Massachusetts

Internal Medicine

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Differential Diagnosis: Neutrophilia

Following are differential diagnoses for patients presented with an elevated neutrophil count.

  • Increased production associated with bone marrow response to inflammation
    • Infection (eg, bacterial, viral, fungal, protozoal) of any organ system 
    • Sterile inflammation (eg, immune-mediated disease, neoplasia, tissue trauma or necrosis) 
  • Increased production associated with bone marrow response to peripheral cytopenias (eg, hemolytic anemia, hemorrhagic anemia, thrombocytopenia) 
  • Glucocorticoid-associated
    • Stress (physical)
    • Glucocorticoid administration
    • Hyperadrenocorticism
  • Granulocytic leukemia
  • Specific infections causing severe leukemoid response 
    • Hepatozoonosis (Hepatozoon canis)
    • Babesiosis (Babesia canis)
  • Leukocyte adhesion deficiencies in dogs (eg, Irish setter), usually associated with hypersegmented neutrophils

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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