HYPERCALCEMIA COMPLICATING SYSTEMIC OXALOSIS IN PRIMARY HYPEROXALURIATYPE-1

Persistent hypercalcaemia was observed in two patients with oxalate os teopathy complicating primary hyperoxaluria type 1; four other cases h ave been reported in the literature. In none of the six patients could hypercalcaemia be ascribed to hyperparathyroidism secondary to renal failure. It occurred in the absence of aluminium intoxication, and was associated with normal calcitriol. Hypercalcaemia responded to mithra mycin in one patient, and to corticosteroid administration in three; c orticosteroid withdrawal was followed by recurrence of hypercalcaemia in the three cases. It is suggested that hypercalcaemia results from t he osteoclast-stimulating activity of macrophages constituting the gra nulomata which invade the bone marrow in response to oxalate depositio n. Whatever its pathogenesis, a trial of corticosteroid appears warran ted for treating hypercalcaemia complicating oxalosis.