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.

Clinical and Pathologic Characteristics Distinguishing Classic CJD from Variant CJD
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 dyesthesiasis; 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
Immunohitochemical 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.