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Disorders of calcium metabolism

2003; Elsevier BV; Volume: 13; Issue: 7 Linguagem: Inglês

10.1016/j.cupe.2003.08.007

1532-2076

Jeremy Allgrove,

Magnesium in Health and Disease

Calcium is crucial for normal neuromuscular activity. It also has a structural role as a component of bone where most of it is present. Plasma calcium is dependent on two main hormones, 1,25-dihydroxyvitamin D and parathyroid hormone, and their interactions with gut absorption, renal excretion and bone mineralization. Disorders of calcium metabolism may result in both hypo- and hypercalcaemia. In children, the former is more common than the latter. Vitamin D undergoes two hydroxylation steps before becoming active. Deficiency or a defect in its metabolism results in rickets, hypocalcaemia or both. Parathyroid hormone is secreted by the parathyroid glands in response to hypocalcaemia under the influence of calcium-sensing receptors. Deficiency of, or failure to respond to, this hormone results in hypocalcaemia, and excess secretion causes hypercalcaemia. Abnormalities of calcium-sensing receptors cause both hypo- and hypercalcaemia. Treatment is directed towards maintaining normal calcium concentrations whilst preventing hypercalciuria.