Which electrolyte abnormality is typically seen with hyperparathyroidism?

Which electrolyte abnormality is typically seen with hyperparathyroidism?

• A. Hypercalcemia with hypophosphatemia
• B. Hypocalcemia with hyperphosphatemia
• C. Hyperkalemia
• D. Hyponatremia

Answer: (A)

Excess parathyroid hormone drives calcium up and phosphate down. PTH raises serum calcium by increasing bone resorption, boosting renal calcium reabsorption, and stimulating production of active vitamin D to enhance gut calcium absorption. At the same time, it lowers phosphate reabsorption in the proximal tubule, leading to phosphaturia and low serum phosphate. The net pattern you’d expect with hyperparathyroidism is high calcium with low phosphate. Other listed abnormalities don’t align with the typical PTH effects on calcium and phosphate.