Acute hyperparathyroidism caused by hemorrhage into a parathyroid adenoma

Acute hyperparathyroidism is a rare and dangerous condition. It is supposed to result from transformation of a mild chronic form into an acute and stormy illness. The causes and the mechanism of such a transformation are usually unknown. A case of acute hyperparathyroidism is presented in which hemorrhage into a parathyroid adenoma was recognized and diagnosed as the immediate cause of the transformation from the mild long-standing form of the disease into the severe acute form.