ABSTRACT
Ninety-nine per cent of the total body calcium is present in the skeleton. The other 1% in extracellular and intracellular fluids plays a vital role in enzyme reactions, coagulation and neuromuscular functioning. Vitamin D, parathyroid hormone (PTH) and calcitonin act on bone, kidneys and gastrointestinal tract to maintain serum calcium concentrations within narrow limits. Hypocalcaemia and hypercalcaemia may be associated with disorders of vitamin D metabolism, parathyroid disease or non-endocrine disorders such as chronic renal failure. Hypocalcaemia is a more common problem than hypercalcaemia in childhood and, apart from excessive ingestion of vitamin D, causes of hypercalcaemia are rare.
