Creutzfeldt-Jakob-Like Syndrome due to Hypercalcemic Encephalopathy.

Hypercalcemia can cause a subacute syndrome of progressive dementia and marked changes in the electroencephalogram (EEG). We report a case of iatrogenic hypercalcemia with a close correlation between the clinical course and the EEG changes. A 73-year-old woman presented with a subacute syndrome of progressive dementia and bursts of 1.5 to 2 Hz intermittent rhythmic delta activity superimposed on a low-voltage background activity in the EEG. Clinical and EEG abnormalities rapidly resolved after normalization of serum calcium levels. As part of the diagnostic workup of a subacute progressive dementia, a serum calcium level and an EEG should be obtained to detect a Creutzfeldt-Jakob like syndrome in hypercalcemia. Unlike in Creutzfeldt-Jakob disease, and Creutzfeldt-Jakob-like syndrome induced by lithium intoxication, there are rarely myoclonic jerks and periodic discharges in hypercalcemic encephalopathy.