Medicine

A 62-year-old woman with CKD Stage 3b (eGFR 35 mL/min/1.73m²) secondary to hypertension is found to have serum potassium 5.8 mEq/L and serum bicarbonate 18 mEq/L. She is on lisinopril 10 mg daily. Which of the following is the BEST approach to managing her hyperkalemia in this setting?

A 55-year-old man with CKD Stage 4 (eGFR 22 mL/min/1.73m²) due to IgA nephropathy is referred for pre-emptive kidney transplant evaluation. His serum calcium is 8.2 mg/dL, phosphate 5.8 mg/dL, and parathyroid hormone (PTH) is 380 pg/mL. Which of the following best describes the pathophysiology of secondary hyperparathyroidism in this patient?

A 70-year-old man with CKD Stage 5 (eGFR 8 mL/min/1.73m²) and a 3-year history of hemodialysis presents with progressive bone pain and muscle weakness. Serum alkaline phosphatase is 120 U/L (normal 30–120), PTH is 850 pg/mL, and bone biopsy shows low bone turnover with minimal osteoid. Which of the following best explains his bone disease and is the MOST appropriate management?