[Primary hyperparathyroidism as a differential diagnosis of Creutzfeldt-Jakob disease].

We report the case of a 79-years-old woman, hospitalized for a suspicion of Creutzfeldt-Jakob disease because of subacute dementia associated with gait disorder. Laboratory testing revealed elevated serum calcium at 3.51 mmol/l (N=2.25-2.60 mmol/l) caused by a hyperparathyroidism. After symptomatic treatment of hypercalcemia by biphosphonate, cognitive functions as well as the gait disorder improved quickly. A double parathyroid adenoma was removed surgically. Primary hyperparathyroidism is a curable cause of a Creutzfeldt-Jakob like syndrome. Serum calcium should be checked in this clinical setting.