MD Endocrine and Metabolic Disorders 3 — Questions and Answers
Question 1: A 28-year-old woman presents with amenorrhea, galactorrhea, and a serum prolactin of 120 ng/mL. MRI shows a 12 mm pituitary lesion. What is the first-line treatment?
- Transsphenoidal surgery
- Radiation therapy
- Dopamine agonist (cabergoline) (Correct answer)
- Bromocriptine + surgery combination
Correct answer: Dopamine agonist (cabergoline)
Dopamine agonists such as cabergoline are the first-line treatment for macroprolactinomas, effectively shrinking the tumor and normalizing prolactin.
Question 2: A patient has hyponatremia with urine osmolality 550 mOsm/kg and urine sodium 60 mEq/L in the setting of recent lung cancer diagnosis. Which syndrome is most likely?
- Cerebral salt wasting
- SIADH (Correct answer)
- Adrenal insufficiency
- Psychogenic polydipsia
Correct answer: SIADH
SIADH associated with ectopic ADH production (e.g., small cell lung cancer) causes euvolemic hyponatremia with concentrated urine and high urine sodium.
Question 3: A 40-year-old woman has a TSH of 0.05 mIU/L and elevated free T4. She reports palpitations, heat intolerance, and a diffuse goiter with bruit on exam. What autoantibody confirms the diagnosis?
- Anti-thyroid peroxidase (anti-TPO)
- Anti-thyroglobulin
- TSH receptor antibody (TRAb) (Correct answer)
- Anti-microsomal antibody
Correct answer: TSH receptor antibody (TRAb)
TSH receptor-stimulating antibodies (TRAb) are pathognomonic for Graves' disease, causing diffuse goiter and hyperthyroidism.
Question 4: A 70-year-old man presents with confusion, polyuria, and blood glucose of 950 mg/dL. Serum bicarbonate is 22 mEq/L and ketones are negative. What is the diagnosis?
- Diabetic ketoacidosis
- Hyperosmolar hyperglycemic state (HHS) (Correct answer)
- Lactic acidosis
- Alcoholic ketoacidosis
Correct answer: Hyperosmolar hyperglycemic state (HHS)
HHS presents with extreme hyperglycemia and hyperosmolarity without significant ketoacidosis, typically in elderly type 2 diabetics.
Question 5: A 35-year-old woman with known MEN1 has recurrent peptic ulcers refractory to PPIs and fasting hypergastrinemia. What additional tumor should be sought?
- Insulinoma
- Gastrinoma (Zollinger-Ellison syndrome) (Correct answer)
- VIPoma
- Glucagonoma
Correct answer: Gastrinoma (Zollinger-Ellison syndrome)
Gastrinoma causing Zollinger-Ellison syndrome is associated with MEN1 and presents with hypergastrinemia and refractory peptic ulcers.
Question 6: Which electrolyte abnormality is the primary life-threatening concern in Addisonian crisis?
- Hyponatremia and hyperkalemia (Correct answer)
- Hypernatremia and hypokalemia
- Hypocalcemia and hyperphosphatemia
- Hypomagnesemia and hypophosphatemia
Correct answer: Hyponatremia and hyperkalemia
Aldosterone deficiency in primary adrenal insufficiency leads to sodium loss and potassium retention, causing potentially fatal hyperkalemia and hyponatremia.
Question 7: A 50-year-old man has an incidentally found 2.5 cm adrenal mass. Workup shows normal cortisol, normal metanephrines, and normal aldosterone/renin ratio. What is the recommended management?
- Immediate surgical resection
- Repeat imaging in 6–12 months (Correct answer)
- Fine-needle aspiration biopsy
- Start empiric ketoconazole
Correct answer: Repeat imaging in 6–12 months
A hormonally inactive adrenal incidentaloma <4 cm with benign imaging features should be monitored with repeat imaging at 6–12 months.
MD Endocrine and Metabolic Disorders 3
A 28-year-old woman presents with amenorrhea, galactorrhea, and a serum prolactin of 120 ng/mL.
MRI shows a 12 mm pituitary lesion.
What is the first-line treatment?