A 59-year-old man with stage 4 chronic kidney disease presents with diffuse bone pain and pruritus. Vital signs: BP 148/92 mmHg, HR 88/min, RR 16/min, temp 37°C. Laboratory studies reveal calcium 7.2 mg/dL, phosphate 5.8 mg/dL, PTH 287 pg/mL, and creatinine 3.1 mg/dL. Renal ultrasound shows normal-sized kidneys without obstruction. He denies recent fractures. Which mechanism best explains the elevated parathyroid hormone?
- A)Primary autonomous secretion from a parathyroid adenoma
- B)Excess intestinal calcium absorption due to increased calcitriol
- C)Suppression of fibroblast growth factor 23
- D)Paraneoplastic PTH related peptide secretion by a renal tumor
- E)Phosphate retention and reduced 1 alpha hydroxylase activity cause secondary hyperparathyroidismGABARITO
Explicação
In chronic kidney disease, phosphate retention and decreased renal 1 alpha hydroxylase activity reduce calcitriol formation, which lowers serum calcium and stimulates secondary hyperparathyroidism. The resulting renal osteodystrophy contributes to bone pain. Ver explicação completa e trilha adaptativa →