Clinical and differential diagnosis of Creutzfeldt-Jakob disease

Until recently, the clinical diagnosis of CJD relied mainly on three criter ia. These include patient history (rapidly progressive dementia), neurologi cal findings (ataxia, pyramidal/extrapyramidal signs, myoclonus, akinetic m utism) and typical electroencephalographic (EEG) findings. These criteria a re fulfilled in typical cases. The occurrence or increase of certain protei ns in cerebrospinal fluid (CSF 14-3-3, neuron-specific enolase) now provide important adjuncts in recognizing variant forms. Although these proteins c an be detected in other neurological diseases accompanied with substantial brain damage such as encephalitis, they are also characterized by their hig h sensitivity and specificity with regard to other dementing processes (Alz heimer and vascular dementia). The increase in the number of positive cases during the last years in Germany reflects an improved case ascertainment r ather than the appearance of the variant CJD (vCJD). Although several recen t cases with a long duration of the disease were actually recognized, they did not reveal the typical florid plaques at autopsy. They were revealed as a rare variant of sporadic CJD, which is characterized by homocygosity for valine at codon 129 and PrPSc type 1. This variant is positive for the 14- 3-3 protein in CSF. Further subtypes described by Parchi et al. [5] can als o be characterized by a certain pattern of clinical symptomatology, EEG- an d 14-3-3-findings. In addition, differential diagnosis revealed some treata ble dementias among the most common diseases (Alzheimer and vascular dement ia) such as herpes encephalitis, multiple sclerosis and Hashimoto encephali tis, particularly in the younger age group.