[Hypercalcemia due to chronic vitamin A use by an elderly patient with renal insufficiency]

An 86-year-old woman presented with anorexia, thirst and nycturia. Laboratory results revealed a hypercalcaemia with renal failure. The patient used 1-6 vitamin A-D tablets daily (1 tablet contains 600 IU retinol palmitate and 200 IU cholecalciferol). The diagnosis was: hypercalcaemia due to chronic vitamin A ingestion. This diagnosis was supported by the finding of the elevated vitamin A concentration in the patient's serum and the exclusion of other causes of hypercalcaemia. In chronic vitamin A ingestion risk factors for vitamin A toxicity are age, body weight and renal insufficiency. The hypercalcaemia caused by chronic vitamin A ingestion is explained through the up-regulation of osteoclasts by retinol metabolites.