Long-term hypervitaminosis D-induced hypercalcaemia treated with glucocorticoids and bisphosphonates

Hypercalcaemia is a common diagnosis with the majority of cases resulting from hyperparathyroidism or malignancy. We report a rare case of persistent symptomatic hypervitaminosis D-induced hypercalcaemia in an individual taking 50 000 IU of vitamin D supplement daily for several months following a diagnosis of vitamin D deficiency. His hypercalcaemia was initially treated with calcitonin and intravenous fluids, but due to recurrent symptomatic hypercalcaemia after discharge, additional treatment with glucocorticoids and bisphosphonates was warranted during his second admission. The pathophysiology of hypercalcaemia from vitamin D intoxication results from the long-term effects of vitamin D storage in adipose tissue. In the present case, we discuss this pathophysiology and treatment approaches in the context of increasing awareness of and testing for vitamin D deficiency, and growing access to over-the-counter supplements.