ITE Endocrinology 2 — Questions and Answers
Question 1: A 45-year-old woman with type 2 diabetes on metformin has an eGFR that drops to 28 mL/min/1.73m². Which medication adjustment is most appropriate?
- Continue metformin at current dose
- Reduce metformin dose by 50%
- Discontinue metformin (Correct answer)
- Switch to metformin XR only
Correct answer: Discontinue metformin
Metformin is contraindicated when eGFR falls below 30 mL/min/1.73m² due to risk of lactic acidosis.
Question 2: A patient with Cushing's disease undergoes transsphenoidal surgery. Post-operatively, serum cortisol is 2 mcg/dL. What does this indicate?
- Surgical failure requiring repeat surgery
- Adrenal insufficiency requiring glucocorticoid replacement (Correct answer)
- Normal post-operative finding requiring no treatment
- Recurrence of hypercortisolism
Correct answer: Adrenal insufficiency requiring glucocorticoid replacement
Very low post-operative cortisol indicates successful tumor removal but requires exogenous glucocorticoid replacement until the HPA axis recovers.
Question 3: Which finding on thyroid ultrasound carries the HIGHEST risk of malignancy?
- Purely cystic nodule >4 cm
- Hyperechoic nodule with comet-tail artifact
- Hypoechoic nodule with microcalcifications and irregular margins (Correct answer)
- Spongiform nodule
Correct answer: Hypoechoic nodule with microcalcifications and irregular margins
Hypoechoic nodules with microcalcifications and irregular margins carry the highest malignancy risk and warrant FNA biopsy.
Question 4: A 32-year-old woman presents with galactorrhea, amenorrhea, and a prolactin level of 210 ng/mL. MRI shows a 12 mm pituitary lesion. First-line treatment is:
- Transsphenoidal surgery
- Bromocriptine or cabergoline (Correct answer)
- External beam radiation
- Observation with repeat MRI in 6 months
Correct answer: Bromocriptine or cabergoline
Dopamine agonists (cabergoline preferred) are first-line treatment for prolactinomas regardless of size.
Question 5: A patient with type 1 diabetes develops recurrent hypoglycemia without adrenergic warning symptoms. This condition is best described as:
- Hypoglycemia-associated autonomic failure (Correct answer)
- Brittle diabetes
- Somogyi phenomenon
- Dawn phenomenon
Correct answer: Hypoglycemia-associated autonomic failure
Hypoglycemia-associated autonomic failure (HAAF) results from prior hypoglycemic episodes blunting counter-regulatory and symptomatic responses.
Question 6: Phentolamine is administered before surgical resection of a pheochromocytoma. What is its primary purpose?
- Prevent tachyarrhythmias during induction
- Block alpha-adrenergic receptors to prevent hypertensive crisis (Correct answer)
- Reduce catecholamine synthesis
- Lower perioperative cortisol levels
Correct answer: Block alpha-adrenergic receptors to prevent hypertensive crisis
Alpha-blockade with phentolamine (or phenoxybenzamine) is essential to prevent severe hypertension from catecholamine release during tumor manipulation.
Question 7: A 55-year-old man has serum calcium of 11.4 mg/dL, PTH of 95 pg/mL (normal 15–65), and normal renal function. Urine calcium-to-creatinine clearance ratio is 0.005. What is the most likely diagnosis?
- Primary hyperparathyroidism
- Familial hypocalciuric hypercalcemia (Correct answer)
- Vitamin D toxicity
- Malignancy-associated hypercalcemia
Correct answer: Familial hypocalciuric hypercalcemia
A urine calcium-to-creatinine clearance ratio <0.01 with hypercalcemia and elevated PTH indicates familial hypocalciuric hypercalcemia (FHH), not primary hyperparathyroidism.
ITE Endocrinology 2
A 45-year-old woman with type 2 diabetes on metformin has an eGFR that drops to 28 mL/min/1.73m².
Which medication adjustment is most appropriate?