Clinical and Pathologic Characteristics
Important Note: Classic CJD is not related to “mad cow” disease. Classic CJD also is distinct from “variant CJD”, another prion disease that is related to BSE.
Classic CJD characteristics, as compared to variant CJD, are presented in the table below.
| Characteristic | Classic CJD | Variant CJD |
|---|---|---|
| Median age at death | 68 years | 28 years |
| Median duration of illness | 4-5 months | 13-14 months |
| Clinical signs and symptoms | Dementia; early neurologic signs | Prominent psychiatric/behavioral symptoms; painful dysesthesias; delayed neurologic signs |
| Periodic sharp waves on electroencephalogram | Often present | Often absent |
| “Pulvinar sign” on MRI* | Not reported | Present in >75% of cases |
| Presence of “florid plaques” on neuropathology | Rare or absent | Present in large numbers |
| Immunohistochemical analysis of brain tissue | Variable accumulation | Marked accumulation of protease-resistance prion protein |
| Presence of agent in lymphoid tissue | Not readily detected | Readily detected |
| Increased glycoform ratio on immunoblot analysis of protease-resistance prion protein | Not reported | Marked accumulation of protease-resistance prion protein |
*An abnormal signal in the posterior thalami on T2- and diffusion-weighted images and fluid-attenuated inversion recovery sequences on brain magnetic resonance imaging (MRI); in the appropriate clinical context, this signal is highly specific for vCJD.
Source: Adapted from Belay E., Schonberger L. Variant Creutzfeldt-Jakob Disease and Bovine Spongiform Encephalopathy. Clin Lab Med 2002;22:849-862.
Page last reviewed: October 18, 2021