Autopsy-proven Creutzfeldt-Jakob disease in a patient with a negative 14-3-3 assay and nonspecific EEG and MRI.

Detection of 14-3-3 protein in cerebrospinal fluid (CSF), in combination with findings on electroencephalography (EEG) and magnetic resonance imaging (MRI), is a highly sensitive and specific diagnostic test for sporadic Creutzfeldt-Jakob disease (CJD) in patients premortem. We present a case of classic, sporadic CJD, confirmed on autopsy and by Western blot. However, all routine premorbid testing was negative, the CSF was negative for the 14-3-3 protein, EEG did not show periodic sharp wave complexes (PSWC), and MRI failed to show hyperintense signal in the basal ganglia. Thus, laboratory support for the diagnosis of CJD was not obtained premortem. The chances of all three diagnostic testing modalities to be negative in a single case of sporadic CJD are extremely remote. Autopsy with neuropathologic confirmation remains the only definitive way to make a diagnosis of CJD.