Severe neurological disease associated with hyperparathyroidism.

Two patients, one with ataxia, internuclear ophthalmoplegia, muscle weakness, atrophy, fasciculations, and bilateral Babinski's signs, the other with dysarthria, dysphagia, muscle weakness, atrophy, fasciculations, and hyperreflexia, had elevated serum calcium and parathyroid hormone levels, establishing the diagnosis of primary hyperparathyroidism (HPT). Removal of a parathyroid adenoma in one patient and three hyperplastic parathyroid glands in the other resulted in remission of the hyperparathyroidism but left both patients with residual neurological damage. Postmortem examination of the second patient showed typical features of amyotrophic lateral sclerosis. The findings in these patients show that hyperparathyroidism may be associated with signs of severe central nervous system disease and that patients with unexplained neurological signs or symptoms should be checked for hyperparathyroidism.