Neuropsychiatric disorders in primary hyperparathyroidism.

This is a report of two middle-aged women whose diagnosis of PHPT was made on hypercalcemia during treatment of depression and paranoid state, leading to the surgical confirmation of parathyroid adenoma. After the operation, their mental symptoms disappeared as the blood level of calcium was depressed in both cases, and there has been no recurrence for 12 and 18 months, respectively. In Case, 1 antipsychotics were effective, though transiently, for the mental symptoms other than physical ones. In Case 2, levodopa and hypercalcemia might have acted synergistically. Abnormal metabolism of magnesium was not noted in either case. A preoperative EEG showed the presence of sporadic slow waves in Case 1 and low voltage activity in Case 2. After the operation, the EEG showed an improvement to regular hypersynchronous alpha activity in both cases. The mechanism involved in the appearance of mental symptoms and EEG findings in hypercalcemia were discussed.