Hypercalcaemia to hypocalcaemia: tetany as a side effect of intravenous bisphosphonate treatment.

A woman in her 40s with advanced bladder cancer was admitted to hospital with hypercalcaemia of malignancy. Initially, she presented with non-specific symptoms of malaise, fatigue and general deterioration. She was treated with intravenous fluids and zoledronic acid in order to bring her calcium levels down, but subsequently developed significant hypocalcaemia.