What is the most common cause of hypocalcemia?

What is the most common cause of hypocalcemia?

• A. Vitamin D deficiency
• B. Renal failure
• C. Hyperphosphatemia
• D. Hypoparathyroidism

Answer: (B)

Renal failure commonly causes hypocalcemia because the kidneys lose their ability to excrete phosphate, leading to hyperphosphatemia. The excess phosphate binds calcium in the blood, lowering the level of free (ionized) calcium. At the same time, diseased kidneys can’t adequately produce calcitriol (the active form of vitamin D), reducing intestinal absorption of calcium. The combination of high phosphate and low calcitriol shifts calcium balance toward hypocalcemia, a pattern frequently seen in patients with chronic kidney disease. While vitamin D deficiency or hypoparathyroidism can cause low calcium, they don’t account for the frequent and overlapping mechanisms seen with renal failure.

Renal failure commonly causes hypocalcemia because the kidneys lose their ability to excrete phosphate, leading to hyperphosphatemia. The excess phosphate binds calcium in the blood, lowering the level of free (ionized) calcium. At the same time, diseased kidneys can’t adequately produce calcitriol (the active form of vitamin D), reducing intestinal absorption of calcium. The combination of high phosphate and low calcitriol shifts calcium balance toward hypocalcemia, a pattern frequently seen in patients with chronic kidney disease. While vitamin D deficiency or hypoparathyroidism can cause low calcium, they don’t account for the frequent and overlapping mechanisms seen with renal failure.