Hypocalcaemia

Hypocalcaemia is a frequent condition resulting from inappropriate loss of calcium from the kidneys or gastrointestinal tract. The condition is most commonly a consequence of hypoparathyroidism or vitamin D deficiency. Hypoparathyroidism most commonly occurs following surgical removal of the parathyroid glands, but may result from auto-immune disease, rare inherited disorders of parathyroid hormone synthesis or action, or from infiltrative diseases that compromise parathyroid gland function. Alternatively, metabolic disturbances can result in hypocalcaemia because of disturbance to the normal homeostatic regulation of extracellular calcium concentrations by the physiological interactions between vitamin D, parathyroid hormone and the calcium-sensing receptor. Vitamin D deficiency is common and results primarily from dietary insufficiency or as a result of reduced synthesis of vitamin D precursors in the skin because of reduced exposure to UV radiation. Secondary vitamin D deficiency may be due to malabsorptive disorders of the gastro-intestinal tract, liver failure or chronic renal impairment. The clinical features, diagnosis, causes and treatment of hypocalcaemia will be reviewed in this article.