Hypoparathyroidism commonly causes which electrolyte abnormality?

Hypoparathyroidism commonly causes which electrolyte abnormality?

• A. Hyperkalemia
• B. Hypercalcemia
• C. Hypernatremia
• D. Hypocalcemia

Answer: (D)

Calcium balance is controlled mainly by parathyroid hormone. When the parathyroids aren’t producing enough hormone, the processes that raise serum calcium slow down: less calcium is released from bone, less calcium is reabsorbed in the kidneys, and less active vitamin D is formed to boost intestinal calcium absorption. The net result is a fall in serum calcium, which is why hypoparathyroidism most commonly presents with hypocalcemia. At the same time, phosphate tends to rise because PTH normally promotes phosphate excretion in the kidneys, so low PTH can lead to hyperphosphatemia. Hyperkalemia and hypernatremia aren’t direct consequences of hypoparathyroidism, since potassium and sodium balance aren’t governed primarily by PTH. Hypercalcemia would occur with excess PTH activity, not with its deficiency.

Calcium balance is controlled mainly by parathyroid hormone. When the parathyroids aren’t producing enough hormone, the processes that raise serum calcium slow down: less calcium is released from bone, less calcium is reabsorbed in the kidneys, and less active vitamin D is formed to boost intestinal calcium absorption. The net result is a fall in serum calcium, which is why hypoparathyroidism most commonly presents with hypocalcemia. At the same time, phosphate tends to rise because PTH normally promotes phosphate excretion in the kidneys, so low PTH can lead to hyperphosphatemia.

Hyperkalemia and hypernatremia aren’t direct consequences of hypoparathyroidism, since potassium and sodium balance aren’t governed primarily by PTH. Hypercalcemia would occur with excess PTH activity, not with its deficiency.