NAVLE Feline Internal Medicine 6

Question 1

A 10-year-old DSH cat presents with polyuria, polydipsia, and a serum fructosamine of 285 µmol/L (reference: 190–365). Blood glucose is 14.2 mmol/L. Which interpretation is most accurate?

Accepted Answer

The fructosamine is within normal range, suggesting stress hyperglycemia rather than DM

Answer

Feline fructosamine reflects average glycemic control over 1–3 weeks. A value of 285 µmol/L falls within the normal reference range (190–365 µmol/L), indicating the hyperglycemia is likely transient (stress-induced) rather than sustained DM. Stress hyperglycemia is common in cats; fructosamine helps differentiate it from true DM. A fructosamine >400 µmol/L typically confirms DM. The other options misapply the reference values or attribute the finding incorrectly.

Question 2

A 7-year-old intact male cat develops acute urethral obstruction. After relief of the obstruction, the cat develops profound bradycardia (HR 48 bpm), peaked T waves on ECG, and a serum potassium of 8.9 mEq/L. Which treatment should be administered FIRST?

Accepted Answer

Calcium gluconate IV to stabilize cardiac membrane potential

Answer

In life-threatening hyperkalemia with cardiac arrhythmias, calcium gluconate is the immediate priority. It does not lower serum potassium but rapidly stabilizes cardiomyocyte membrane potential, buying time to address the underlying cause. Insulin/dextrose and sodium bicarbonate do shift potassium intracellularly but take longer to act and do not protect the heart as immediately. Furosemide requires adequate renal function and acts too slowly in an acute crisis.

Question 3

A 12-year-old hyperthyroid cat is treated with methimazole and achieves euthyroidism. Six weeks later, serum creatinine rises from 1.4 to 3.8 mg/dL and BUN from 22 to 68 mg/dL. Urine specific gravity is 1.018. What is the most accurate explanation for this finding?

Accepted Answer

Hyperthyroidism had been masking pre-existing chronic kidney disease by increasing GFR

Answer

Hyperthyroidism increases cardiac output and renal blood flow, artificially elevating GFR and masking underlying CKD. When euthyroidism is restored, renal perfusion normalizes (decreases), and true CKD becomes apparent. This is a well-recognized phenomenon in feline medicine — it underscores the importance of renal function assessment before and after initiating treatment. Methimazole is not directly nephrotoxic in this manner, and the urine specific gravity of 1.018 indicates reduced concentrating ability consistent with CKD, not dehydration alone.

Question 4

A cat presents with a 3-week history of weight loss, icterus, and anorexia. Abdominal ultrasound reveals a diffusely hyperechoic liver. Cytology of a fine-needle aspirate shows >50% of hepatocytes containing large cytoplasmic lipid vacuoles. Serum ALT is 3× ULN; ALP is only mildly elevated. Which statement about this condition is most accurate?

Accepted Answer

Aggressive nutritional support via feeding tube is a cornerstone of treatment, as anorexia perpetuates the condition

Answer

This is hepatic lipidosis (HL), the most common hepatopathy in cats. Unlike dogs, cats have low hepatic ALP activity and a short isoenzyme half-life, so ALP elevation is often mild even in severe HL — making option A partially true but not the most clinically useful statement. The critical management principle is that HL is driven by continued anorexia and negative energy balance; aggressive nutritional support (esophagostomy or gastrostomy tube) is essential to reverse hepatocyte lipid accumulation. HL is not self-limiting without intervention, and mild ALP does not distinguish HL from biliary disease by itself.

Question 5

A 9-year-old cat with a 2-month history of small-bowel diarrhea and weight loss undergoes intestinal biopsy. Histopathology reveals mucosal architectural distortion, villous blunting, and a mixed population of lymphocytes and plasma cells. Immunohistochemistry shows a CD3+/CD20− predominant infiltrate. What is the most appropriate next diagnostic step to distinguish small cell lymphoma from inflammatory bowel disease?

Accepted Answer

PARR (PCR for antigen receptor rearrangement) to assess clonality of the lymphocyte population

Answer

Distinguishing feline small cell (low-grade) lymphoma from lymphoplasmacytic IBD is one of the most challenging problems in feline gastroenterology, as both share similar histologic appearances and CD3+ T-cell infiltrates. PARR (PCR for antigen receptor rearrangement) assesses whether the lymphocyte population is clonal (lymphoma) or polyclonal (reactive/IBD) and is the gold-standard adjunct test when histology is equivocal. Response to steroids is not definitive because both IBD and small cell lymphoma can respond to chlorambucil/prednisolone. Cobalamin/folate confirms small intestinal involvement but does not differentiate the two diseases. Deeper biopsies improve histologic yield but do not resolve the clonality question.

NAVLE - North American Veterinary Licensing Examination Practice Test

NAVLE - North American Veterinary Licensing Examination Practice Test

NAVLE Feline Internal Medicine 6