Severe hypocalcaemia associated with extensive osteoblastic metastases in a patient with prostate cancer

A patient with an untreated carcinoma of the prostate was admitted with dehydration, stupor and a surprisingly deep hypocalcaemia. The severe hypocalcaemia was largely attributed to extensive osteoblastic activity due to widespread skeletal metastases although contributing factors to the severity of the hypocalcaemia were a relative vitamin D deficiency, hypomagnesaemia and renal impairment, preventing the mounting of an adequate homeostatic response. There was significant clinical and biochemical improvement after antitumour treatment using androgen deprivation, and supplementation with calcium and vitamin D.