ITE Endocrinology 4 — Questions and Answers
Question 1: A 40-year-old woman presents with hypertension, hypokalemia, and suppressed plasma renin activity. Aldosterone-to-renin ratio is markedly elevated. What is the next best diagnostic step?
- Proceed directly to adrenal vein sampling
- Confirm with oral sodium loading or fludrocortisone suppression test (Correct answer)
- Start spironolactone empirically
- Obtain urine catecholamines
Correct answer: Confirm with oral sodium loading or fludrocortisone suppression test
An elevated aldosterone-to-renin ratio is a screening test; confirmatory testing (salt loading or fludrocortisone suppression) is required before adrenal imaging or vein sampling.
Question 2: A 25-year-old man is found to have bilateral adrenal masses and hypertension. Urine metanephrines are markedly elevated. Before surgical planning, which additional workup is mandatory?
- Thyroid function tests
- Serum calcitonin and RET proto-oncogene mutation testing (Correct answer)
- Serum aldosterone-to-renin ratio
- 24-hour urine cortisol
Correct answer: Serum calcitonin and RET proto-oncogene mutation testing
Bilateral pheochromocytoma raises concern for MEN2 or VHL; serum calcitonin screens for medullary thyroid cancer and RET mutation testing identifies MEN2.
Question 3: Which of the following features most strongly differentiates papillary thyroid carcinoma from follicular thyroid carcinoma on fine needle aspiration?
- Colloid abundance
- Nuclear grooves, pseudoinclusions, and Orphan Annie eye nuclei (Correct answer)
- Hurthle cell metaplasia
- Psammoma bodies in follicular architecture
Correct answer: Nuclear grooves, pseudoinclusions, and Orphan Annie eye nuclei
Papillary thyroid carcinoma is diagnosed by characteristic nuclear features: grooves, pseudo-inclusions, and pale (Orphan Annie eye) nuclei on cytology.
Question 4: A 35-year-old woman with type 1 diabetes develops nausea, hypotension, hyponatremia, and hyperkalemia. Morning cortisol is 3 mcg/dL. What diagnosis must be ruled out immediately?
- Diabetic ketoacidosis
- Primary adrenal insufficiency (Addison disease) (Correct answer)
- SIADH
- Mineralocorticoid excess
Correct answer: Primary adrenal insufficiency (Addison disease)
The combination of hyponatremia, hyperkalemia, hypotension, and low cortisol in a T1DM patient is classic for autoimmune primary adrenal insufficiency.
Question 5: A patient on amiodarone develops fatigue, weight gain, and bradycardia. TSH is 42 mIU/L and free T4 is 0.4 ng/dL. What is the most appropriate management?
- Discontinue amiodarone only
- Start levothyroxine replacement (Correct answer)
- Administer Lugol's iodine
- Obtain thyroid ultrasound and defer treatment
Correct answer: Start levothyroxine replacement
Amiodarone-induced hypothyroidism requires levothyroxine replacement; amiodarone discontinuation is often not feasible due to underlying cardiac disease.
Question 6: A 50-year-old man with type 2 diabetes has an HbA1c of 9.2% despite maximum metformin. He has established atherosclerotic cardiovascular disease. Which agent should be added next according to current guidelines?
- Sulfonylurea
- DPP-4 inhibitor
- GLP-1 receptor agonist with proven CV benefit (Correct answer)
- Thiazolidinedione
Correct answer: GLP-1 receptor agonist with proven CV benefit
ADA guidelines prioritize GLP-1 receptor agonists with proven cardiovascular benefit (liraglutide, semaglutide) or SGLT-2 inhibitors in patients with established ASCVD.
Question 7: An insulinoma is suspected in a patient with fasting hypoglycemia. Which laboratory finding pattern is diagnostic?
- Low insulin, low C-peptide, low proinsulin
- High insulin, high C-peptide, high proinsulin, negative sulfonylurea screen (Correct answer)
- High insulin, low C-peptide, negative sulfonylurea screen
- High insulin, high C-peptide, positive sulfonylurea screen
Correct answer: High insulin, high C-peptide, high proinsulin, negative sulfonylurea screen
Insulinoma produces endogenous insulin with elevated C-peptide and proinsulin; exogenous insulin use causes low C-peptide, and sulfonylurea abuse is excluded by drug screen.
ITE Endocrinology 4
A 40-year-old woman presents with hypertension, hypokalemia, and suppressed plasma renin activity.
Aldosterone-to-renin ratio is markedly elevated.
What is the next best diagnostic step?