Reversible Cause of Rapidly Progressive Dementia as Presenting Symptom of Primary Hyperparathyroidism

Primary hyperparathyroidism (PHPT) is imbalance of calcium, phosphate, and bone metabolism attributed to an increased secretion of parathyroid hormone (PTH). Although PHPT is mainly associated with musculoskeletal and kidney dysfunction, variable symptoms can be presented in the elderly patients. A 75-year-old man presented with rapidly progressive dementia (RPD). Through etiological work-up of hypercalcemia and increased PTH, parathyroid adenoma was found. Subtotal parathyroidectomy resulted in recovery of cognitive impairment. Primary hyperparathyroidism should be considered in a differential diagnosis of RPD.