NAVLE Feline Internal Medicine 5

Question 1

A 10-year-old DSH cat presents with polyuria, polydipsia, and a serum potassium of 2.8 mEq/L. Blood pressure is 195 mmHg. Aldosterone-to-renin ratio is markedly elevated. CT reveals a 1.2 cm unilateral adrenal mass. Which of the following is the MOST appropriate next step in management?

Accepted Answer

Adrenalectomy after preoperative potassium and blood pressure stabilization

Answer

Feline primary hyperaldosteronism (Conn's syndrome) caused by a unilateral adrenal adenoma or carcinoma is best treated with adrenalectomy, which is curative. Preoperative stabilization with potassium supplementation and amlodipine (the preferred antihypertensive in cats) is essential to reduce anesthetic risk. Medical management alone is reserved for bilateral disease or poor surgical candidates. A dexamethasone suppression test is not indicated here as there is no evidence of hypercortisolism. Bilateral adrenalectomy is inappropriate for confirmed unilateral disease.

Question 2

A 7-year-old spayed female cat is diagnosed with intermediate-grade small cell lymphoma of the GI tract confirmed via full-thickness biopsy showing transmural infiltration with loss of normal architecture. Which chemotherapy protocol is MOST appropriate compared to the standard low-grade (small cell) lymphoma protocol?

Accepted Answer

CHOP-based protocol (cyclophosphamide, doxorubicin, vincristine, prednisolone)

Answer

Intermediate- to high-grade feline GI lymphoma (large cell lymphoma) carries a significantly worse prognosis than the indolent small cell (low-grade) form and requires a more aggressive CHOP-based multi-agent protocol. The chlorambucil/prednisolone protocol used for small cell lymphoma is insufficient for large or intermediate cell disease. Single-agent lomustine has activity in some lymphomas but is not the standard of care here. Toceranib targets receptor tyrosine kinases and is not the treatment of choice for GI lymphoma.

Question 3

A cat is presented for evaluation of recurrent upper respiratory signs and oral ulcerations. FHV-1 PCR is positive on conjunctival swab. Which of the following statements about feline herpesvirus-1 pathophysiology is MOST accurate?

Accepted Answer

Latency is established in trigeminal ganglia; reactivation may be subclinical and shedding can occur without overt signs

Answer

FHV-1 establishes latency primarily in the trigeminal ganglia. Reactivation, triggered by stress or immunosuppression, does not always produce overt clinical disease — cats can shed virus asymptomatically, which has significant implications for multi-cat environments. Persistent viremia does not occur; PCR on conjunctival or nasal swabs is the preferred diagnostic approach. Famciclovir reduces viral replication and severity of clinical signs but does not eliminate latent virus — recurrence remains possible.

Question 4

A 12-year-old cat with well-regulated hyperthyroidism (post-radioiodine therapy, now euthyroid) develops azotemia (creatinine 3.1 mg/dL, BUN 58 mg/dL). Prior to treatment, renal parameters were within normal limits. What is the MOST likely explanation for this finding?

Accepted Answer

Hyperthyroidism increased GFR and masked pre-existing chronic kidney disease; euthyroidism unmasked it

Answer

Hyperthyroidism increases cardiac output and renal blood flow, artificially elevating GFR and masking underlying CKD by keeping creatinine and BUN within normal limits. Once hyperthyroidism is treated and the cat becomes euthyroid, GFR normalizes (or decreases), and pre-existing CKD is 'unmasked.' This is a well-recognized phenomenon in feline medicine and is why a post-treatment renal function decline does not necessarily indicate a treatment complication. Radioiodine is not directly nephrotoxic, and acute ischemic injury from mild post-treatment hypothyroidism is not a recognized complication.

Question 5

A 9-year-old cat presents with pleural effusion. Thoracocentesis yields a fluid with total protein 5.2 g/dL, nucleated cell count 4,200 cells/µL (predominantly non-degenerate neutrophils and macrophages), and a cholesterol-to-triglyceride ratio less than 1. Fluid triglycerides are 320 mg/dL. What is the MOST likely diagnosis?

Accepted Answer

Chylothorax

Answer

Chylothorax is characterized by a milky, triglyceride-rich effusion. The hallmark diagnostic criteria include pleural fluid triglycerides exceeding serum triglycerides (and typically >100 mg/dL) and a cholesterol-to-triglyceride ratio less than 1. Cytology typically shows small lymphocytes and non-degenerate neutrophils/macrophages, consistent with this case. FIP effusions are typically high-protein exudates but with lower cell counts and a higher cholesterol:triglyceride ratio. Pyothorax produces a septic exudate with degenerate neutrophils and intracellular bacteria. A pure transudate would have low protein and low cellularity.

NAVLE - North American Veterinary Licensing Examination Practice Test

NAVLE - North American Veterinary Licensing Examination Practice Test

NAVLE Feline Internal Medicine 5