Thyroid Disorders USMLE Step 1 Practice Question
A 56-year-old woman presents with constipation, depressed mood, and a history of recurrent kidney stones. Vital signs: BP 138/88 mmHg, HR 58 bpm, RR 14, Temp 36.8°C, SpO2 98%. Laboratory studies show serum calcium 11.2 mg/dL (elevated), phosphate 2.1 mg/dL (low), and PTH 156 pg/mL (elevated). Serum TSH is normal. Abdominal imaging reveals calcium oxalate nephrolithiasis. Which of the following is the most likely underlying cause of her biochemical abnormalities?
Answer choices
- AVitamin D deficiency
- BChronic kidney disease
- CPseudohypoparathyroidism
- DAutoimmune destruction of parathyroid glands
- EParathyroid adenomaCorrect answer
- FFamilial hypocalciuric hypercalcemia from inactivating CaSR mutation
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.