hipocalcemia

Hypocalcemia is a condition characterized by low levels of calcium in the blood. Total serum calcium is typically considered low below about 8.5 mg/dL (2.12 mmol/L), while ionized calcium below about 1.12 mmol/L is also diagnostic. Because calcium binds to albumin, total calcium can be misleading in people with abnormal albumin; ionized calcium measurements or corrected calcium calculations are used when appropriate.

Causes include reduced secretion or action of parathyroid hormone (hypoparathyroidism, including postsurgical or autoimmune cases), vitamin D deficiency or resistance, chronic kidney disease, pancreatitis, and magnesium deficiency. Other contributing factors are acute illness, transfusion with citrate, malnutrition, alkalosis, and medications such as loop diuretics, certain anticonvulsants, and bisphosphonates.

Symptoms range from perioral tingling and numbness to muscle cramps, tetany, carpopedal spasm, seizures, and arrhythmias. Some patients may have QT prolongation on ECG. Signs may include positive Chvostek or Trousseau signs.

Evaluation typically includes calcium measurement with correction for albumin or direct measurement of ionized calcium, along with magnesium, phosphate, PTH, renal function, and vitamin D status. Assessment for underlying causes guides treatment.

Management depends on severity. Acute, symptomatic hypocalcemia requires prompt intravenous calcium (often calcium gluconate) with cardiac monitoring. Chronic management uses oral calcium supplementation and active vitamin D (e.g., calcitriol), addressing underlying causes, and correcting magnesium deficiency if present. Regular follow-up calcium checks are recommended.