DVM Clinical Pathology and Diagnostics 4 — Questions and Answers
Question 1: A cow presents with milk fever. Which serum electrolyte abnormality is expected?
- Hyperkalemia
- Hypercalcemia
- Hypocalcemia (Correct answer)
- Hyperphosphatemia
Correct answer: Hypocalcemia
Milk fever (parturient paresis) is caused by hypocalcemia due to the sudden calcium demand at the onset of lactation exceeding homeostatic mechanisms.
Question 2: A dog with splenic hemangiosarcoma is presented. Which CBC finding would most strongly support active hemorrhage into the abdominal cavity?
- Mature neutrophilia
- Regenerative anemia with thrombocytopenia and schistocytes (Correct answer)
- Lymphocytosis
- Polycythemia
Correct answer: Regenerative anemia with thrombocytopenia and schistocytes
Regenerative anemia with thrombocytopenia and red cell fragmentation (schistocytes) suggests hemorrhage combined with microangiopathic changes, common with hemangiosarcoma.
Question 3: An ACTH stimulation test in a dog yields a pre-cortisol of 2 µg/dL and post-cortisol of 2.5 µg/dL. What does this confirm?
- Pituitary-dependent hyperadrenocorticism
- Adrenal-dependent hyperadrenocorticism
- Hypoadrenocorticism (Correct answer)
- Normal adrenal function
Correct answer: Hypoadrenocorticism
A blunted cortisol response to ACTH (both pre- and post-stimulation values low or below normal) confirms hypoadrenocorticism (Addison's disease).
Question 4: Which stain is most appropriate for identifying lipid droplets in hepatocytes on a liver fine-needle aspirate?
- Prussian blue
- Oil Red O on air-dried unfixed sample (Correct answer)
- PAS stain
- Gram stain
Correct answer: Oil Red O on air-dried unfixed sample
Oil Red O stains neutral lipids red/orange and must be applied to unfixed, air-dried smears before lipids dissolve during routine processing.
Question 5: A feline patient has a packed cell volume of 55% and a concurrent low erythropoietin level. What is the most likely underlying cause?
- Primary erythrocytosis (polycythemia vera) (Correct answer)
- Dehydration-induced relative polycythemia
- Secondary erythrocytosis from chronic hypoxia
- Iron deficiency anemia
Correct answer: Primary erythrocytosis (polycythemia vera)
Primary erythrocytosis (polycythemia vera) is a myeloproliferative disorder where erythropoietin is suppressed due to autonomous RBC overproduction.
Question 6: A dog's urine protein:creatinine (UPC) ratio is 4.2 with no active sediment. What is the most likely diagnosis?
- Pre-renal proteinuria from fever
- Glomerulonephropathy (Correct answer)
- Lower urinary tract inflammation
- Post-renal hemorrhage
Correct answer: Glomerulonephropathy
A UPC ratio above 2.0 with inactive sediment and no lower urinary tract disease strongly suggests glomerulonephropathy as the source of proteinuria.
Question 7: A caprine blood smear shows Heinz bodies on new methylene blue stain. Which toxin is most commonly responsible in goats?
- Organophosphate
- Lead
- Copper (Correct answer)
- Nitrate
Correct answer: Copper
Copper toxicity in small ruminants causes oxidative damage to hemoglobin, forming Heinz bodies and leading to intravascular hemolytic crisis.
DVM Clinical Pathology and Diagnostics 4
A cow presents with milk fever.
Which serum electrolyte abnormality is expected?