NAVLE General Practice 6

Question 1

A 7-year-old intact male Shetland Sheepdog presents with bilateral symmetric alopecia, hyperpigmentation, and a 'rat tail' appearance. Serum chemistry reveals hypercholesterolemia and mild elevations in ALP. An ACTH stimulation test is normal. Which additional diagnostic test is most appropriate to confirm the suspected diagnosis?

Accepted Answer

GnRH stimulation test measuring testosterone and estradiol

Answer

The clinical picture — bilateral flank alopecia, hyperpigmentation, and 'rat tail' in an intact male — is classic for sex hormone-related alopecia (hyperandrogenism or adrenal sex hormone excess). A normal ACTH stimulation test rules out typical hyperadrenocorticism. A GnRH stimulation test measures testosterone and estradiol pre- and post-stimulation to identify testicular or adrenal sex hormone overproduction, which is the key next step. Castration is both diagnostic and therapeutic in many such cases.

Question 2

A 4-year-old domestic shorthair cat presents with a 3-week history of progressive neurological signs including head tremors, cerebellar ataxia, and vertical nystagmus. The owner recently moved from the Ohio River Valley. CSF analysis shows eosinophilic pleocytosis. Serum Cryptococcus antigen is negative. Which organism is the most likely causative agent?

Accepted Answer

Blastomyces dermatitidis

Answer

Blastomyces dermatitidis is endemic to the Ohio and Mississippi River Valleys and can cause CNS blastomycosis in cats, presenting with granulomatous meningoencephalitis and eosinophilic pleocytosis. The geographic history is a critical clue. While Toxoplasma is common in cats, it typically causes mixed or neutrophilic pleocytosis and is not geographically restricted. Cuterebra larval migration is possible but does not fit as neatly with the endemic area history. Coccidioides is southwestern U.S., not the Ohio Valley.

Question 3

A 10-year-old Labrador Retriever is being managed for degenerative joint disease with long-term meloxicam. The owner reports the dog has developed polyuria and polydipsia over the past 6 weeks. Serum creatinine is 2.4 mg/dL (baseline 1.0 mg/dL), BUN 52 mg/dL, phosphorus 6.8 mg/dL, and urine specific gravity 1.014. Blood pressure is 178/112 mmHg. Which combination of interventions is most appropriate as the FIRST priority?

Accepted Answer

Discontinue meloxicam, initiate amlodipine, begin phosphate binder therapy, and start subcutaneous fluids

Answer

This dog has IRIS Stage 2–3 CKD with concurrent hypertension and hyperphosphatemia. The NSAID must be discontinued immediately as it contributes to renal vasoconstriction and worsening CKD. Hypertension at this level (>160 mmHg systolic) requires immediate treatment with amlodipine (first-line antihypertensive in dogs). Hyperphosphatemia above 6 mg/dL in CKD warrants phosphate binder initiation. Subcutaneous fluids support renal perfusion. Waiting to address hypertension or hyperphosphatemia would allow ongoing target organ damage.

Question 4

A 6-month-old female intact pig (Sus scrofa domesticus) raised as a pet presents with acute onset of paddling, opisthotonus, and salivation. The owner reports feeding table scraps including salted pork rinds and leftover soup. On exam the pig is non-febrile but disoriented. CSF tap shows increased protein with no organisms on Gram stain. Which diagnosis best explains this presentation?

Accepted Answer

Salt poisoning / water deprivation encephalopathy

Answer

Salt poisoning (sodium ion toxicosis) in pigs occurs classically when animals with water deprivation are suddenly allowed free water intake, OR when fed high-sodium diets without adequate water access. The CSF findings of elevated protein with no organisms, combined with the high-sodium diet history (salted pork rinds, soup), point strongly to this diagnosis. The classic histopathologic finding is eosinophilic meningoencephalitis with perivascular cuffing. Streptococcus suis would typically show CSF neutrophilia and organisms. Pseudorabies causes intense pruritus ('mad itch') and is reportable. Mulberry heart disease presents with sudden death, not CNS signs.

Question 5

A 12-year-old Quarter Horse mare presents with a 48-hour history of weight shifting, bilateral forelimb lameness, and divergent hoof rings. Digital pulses are bounding in all four feet. Radiographs reveal a 12-degree rotation of P3 with a 6 mm sole depth in the left front foot. Which statement regarding prognosis and management is most accurate?

Accepted Answer

The combination of >11.5-degree rotation AND <6 mm sole depth defines a negative prognosis threshold; this case is borderline and surgical options such as deep digital flexor tenotomy should be considered

Answer

The critical prognostic thresholds in equine laminitis are rotation >11.5 degrees AND sole depth <6 mm simultaneously — this combination correlates strongly with poor outcome. This mare sits right at these thresholds (12-degree rotation, 6 mm sole depth), making her prognosis guarded and warranting serious consideration of deep digital flexor tenotomy (DDFT tenotomy) to relieve pull on the distal phalanx. Sole depth ≥5 mm is actually a relatively negative threshold, not favorable. Rotation alone beyond 10 degrees is not an absolute euthanasia criterion. Venography is actually valuable in these cases to assess lamellar blood flow and guide prognosis.

NAVLE - North American Veterinary Licensing Examination Practice Test

NAVLE - North American Veterinary Licensing Examination Practice Test

NAVLE General Practice 6