A 72-year-old woman on chronic hydrochlorothiazide for hypertension presents with asymptomatic hypercalcemia. Vital signs: BP 142/88 mmHg, HR 76/min, RR 16/min, Temp 37.2°C. Laboratory findings: serum calcium 11.5 mg/dL, phosphate 3.5 mg/dL, PTH 18 pg/mL, 25-OH vitamin D 38 ng/mL, and 24-hour urine calcium 180 mg/24h. Serum creatinine is normal. Parathyroid imaging shows no adenoma. Which mechanism best explains these findings?
- A)Thiazide-induced hyperparathyroidism
- B)Secondary hyperparathyroidism from sodium depletion
- C)Thiazide-induced suppression of PTH secretion
- D)Vitamin D toxicity from increased intestinal absorption
- E)Unmasking of underlying primary hyperparathyroidism by thiazideGABARITO
Explicação
Thiazide diuretics cause mild hypercalcemia by decreasing urinary calcium excretion in the distal tubule. However, if a patient is found with hypercalcemia and suppressed PTH while on thiazides, the thiazide likely unmasked pre-existing primary hyperparathyroi... Ver explicação completa e trilha adaptativa →