Calcium and Parathyroid USMLE Step 1 Practice Question
A 34-year-old woman with short stature and round facies presents with paresthesias and muscle cramps. Vital signs: BP 128/82, HR 92, RR 16, Temp 37°C, SpO2 98%. Laboratory findings reveal severe hypocalcemia (6.2 mg/dL), hyperphosphatemia (7.1 mg/dL), and undetectable PTH (<5 pg/mL). Physical examination demonstrates shortened fourth and fifth metacarpals bilaterally. She reports neck surgery at age 8 with no recent medication use. Which diagnosis best explains these findings?
Answer choices
- APseudohypoparathyroidism with PTH resistance
- BSurgical hypoparathyroidism from inadvertent parathyroid removal
- CDiGeorge syndrome (22q11 deletion) with thymic hypoplasia and hypoparathyroidismCorrect answer
- DVitamin D-dependent rickets type 1 with low 1,25-dihydroxyvitamin D
- EChronic kidney disease with tertiary hyperparathyroidism
- FKenny-Caffey syndrome as a rare congenital hypoparathyroidism with osteosclerosis and tubular bone stenosis
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