Issue: 2003 > November > case report

Unexpected prolonged extreme hypocalcaemia and an inadequate PTH response in a patient with metastatic breast carcinoma

F.J.M. Bergkamp, A.M. van Berkel, P.W.G. van der Linden, J.P.M.C. Gorgels


Although hypercalcaemia is often encountered during the
course of malignant disease, hypocalcaemia appears to be rather rare. We describe a 37-year-old patient with
metastatic carcinoma of the breast, who developed
extreme hypocalcaemia (as low as 0.75 mmol calcium per litre) after chemotherapy. This is caused by a combination of hungry-bone syndrome and an insufficient parathyroid response. The latter may be the result of a direct toxic effect of chemotherapy on parathyroid hormone (PTH) synthesis possibly in combination with microscopic tumour infiltration in the parathyroid glands. Correction of the extreme hypocalcaemia over a period of 100 days by oral and intravenous calcium supplementation, corresponding
to a total of 352 gram elemental calcium (1/3 of the total
body calcium), resulted in gradual symptomatic relief. The possible mechanisms for these findings are discussed and the literature is briefly reviewed.