A 7-year-old boy presents with muscle cramps, paresthesias, and positive Chvostek sign. Vital signs show HR 102 bpm, BP 118/76 mmHg, RR 18, temp 37°C, SpO2 98%. Serum calcium is 6.8 mg/dL (normal 8.5-10.5), phosphate 6.2 mg/dL (normal 2.5-4.5), PTH 312 pg/mL (normal 15-65), and magnesium 2.1 mg/dL (normal 1.7-2.2). Serum creatinine is normal. He denies recent neck surgery or radiation. Which of the following is the most likely diagnosis?
- A)Autosomal dominant hypocalcemia
- B)Pseudohypoparathyroidism type Ia
- C)Nutritional rickets from vitamin D deficiency
- D)Vitamin D-dependent rickets type 2
- E)Vitamin D-dependent rickets type 1GABARITO
Explicação
Vitamin D-dependent rickets type 1 (VDDR1) results from 1-alpha-hydroxylase deficiency, causing inability to produce active 1,25-dihydroxy vitamin D. This presents with severe hypocalcemia, hyperphosphatemia, markedly elevated PTH, and normal kidney function—d... Ver explicação completa e trilha adaptativa →