Calcium imbalance in hypoparathyroidism.

Extracellular fluid calcium is a tightly controlled variable. Hypoparathyroid state may result in profound calcium imbalance and moderate to severe hypocalcaemia. During 1974-89, 108 cases of hypoparathyroidism (97 post-surgical and 11 idiopathic) were seen. In the post-thyroidectomy group, 83 cases (85%) presented with acute transient hypocalcaemia with spontaneous recovery within 7-10 days. Chronic hypoparathyroidism was seen in 25 cases (14 post-surgical and 11 idiopathic). Convulsions resembling epileptic fits were seen in 9 cases (36%). Pseudopapilloedema was seen in three cases presenting with fits. The administration of phenobarbitone and dilantin aggravated convulsions in 9 patients. The other manifestations were psychiatric illness, cataract and calcification of basal ganglion. Biochemical findings included persistent hypocalcaemia with normal or raised serum phosphorus and lowered daily urinary excretion of calcium. Twenty three of 25 chronic hypoparathyroid cases were treated with vitamin D3 (1-3 mg/day) and calcium supplements (600-1000 mg/day)while 1 alfa-calcidol or calcitriol was used in two patients. Four patients receiving treatment with vitamin D3 developed transient hypercalcaemia with raised plasma levels of 25 hydroxy-vitamin D3. They responded to a reduction in dosage of vitamin D3. One patient was later changed over to 1-alfa-calcidol and another to calcitriol.