Late-onset hypocalcemia is associated with renal retention of phosphorus. Which electrolyte finding is typically seen?

• A. Hypernatremia
• B. Hyperphosphatemia
• C. Hyponatremia
• D. Hypophosphatemia

Answer: (B)

In this scenario, the key idea is that the kidneys retain phosphate, leading to hyperphosphatemia. When phosphate levels rise, phosphate readily binds calcium, reducing the amount of free (ionized) calcium in the blood and contributing to hypocalcemia. So the expected electrolyte finding is elevated phosphate levels. Sodium abnormalities are not a defining feature of this pattern, and a low phosphate level would contradict the story of phosphate retention.