Diagnosing Creutzfeldt-Jakob diseaseBMJ 1996; 313 doi: https://doi.org/10.1136/bmj.313.7061.833 (Published 05 October 1996) Cite this as: BMJ 1996;313:833
- Robert Will, Consultant neurologist,
- Martin Zeidler, Research fellow
- National Creutzfeldt-Jakob Disease Surveillance Unit, Western General Hospital, Edinburgh EH4 2XU
Case identification depends on neurological and neuropathological assessment
Central to the identification and classification of patients with Creutzfeldt-Jakob disease (CJD) is the application of standardised diagnostic criteria based on accumulated data on the clinical and pathological features of the disease. Typically, patients present clinically with rapidly progressive dementia and myoclonus associated with various focal neurological signs. The diagnosis is confirmed by identifying characteristic neuropathological features, which include spongiform change, astrocytic gliosis, and neuronal loss. Diagnostic criteria originally proposed in 19791 have been validated by the “gold standard” of experimental transmissibility in primates.2 This indicates that the clinical diagnosis is highly accurate, particularly if there is a characteristic appearance on an electroencephalogram.
However, not all cases are straightforward: about 10% of patients have a protracted clinical course, which makes the distinction from Alzheimer's disease difficult3; 20–40% of patients do not exhibit a typical electroencephalogram4; and unusual clinical phenotypes occur in patients with genetic and iatrogenic forms of the disease.4 Updated diagnostic criteria have been published, including new definitions for “familial” and iatrogenic Creutzfeldt-Jakob disease,5 but case ascertainment in the small proportion of atypical cases depends on review of a wide spectrum of suspect cases and a high necropsy rate.
Since 1990 in Britain, the criterion for referral to the National Creutzfeldt-Jakob Disease Surveillance Unit has been any suspected case, and about 70% of these cases will go to necropsy. About half of all suspect cases fulfil criteria for …