A 66-year-old man with squamous cell carcinoma of the lung presents with constipation, confusion, and dehydration. Vital signs show BP 148/92, HR 102, RR 18, temp 37.2°C. Laboratory studies reveal serum calcium 12.8 mg/dL, phosphate 2.1 mg/dL, and suppressed PTH at 15 pg/mL. Chest X-ray confirms the known malignancy. He denies bone pain or recent thiazide use. Which mediator most likely causes his metabolic abnormality?
- A)Parathyroid hormone related peptideGABARITO
- B)Excess 1,25 dihydroxyvitamin D from the kidney
- C)Erythropoietin
- D)Thyroid stimulating immunoglobulin
- E)Calcitonin
Explicação
Squamous cell carcinoma commonly causes humoral hypercalcemia of malignancy through secretion of parathyroid hormone related peptide. PTHrP mimics many actions of PTH, producing hypercalcemia and hypophosphatemia while suppressing native PTH. The cancer histor... Ver explicação completa e trilha adaptativa →