CJD Diagnostic Criteria | Classic CJD

Sporadic CJD

Definite

Diagnosed by standard neuropathological techniques

• And/Or immunocytochemically
• And/Or Western blot confirmed protease-resistant PrP
• And/Or presence of scrapie-associated fibrils.

Probable

Neuropsychiatric disorder plus positive RT-QuIC in cerebrospinal fluid (CSF) or other tissues.

OR

Rapidy progressive dementia and at least two out of these four clinical features:

• Myoclonus
• Visual or cerebellar signs
• Pyramidal/extrapyramidal signs
• Akinteic mutism

AND

A positive result on at least one of the following laboratory tests:

• a typical EEG (periodic sharp wave complexes) during an illness of any duration
• a positive 14-3-3 CSF assay in patients with a disease duration of less than 2 years
• High signal in caudate/putamen on magnetic resonance imaging (MRI) brain scan or at least two cortical regions (temporal, parietal, occipital) either on diffusion-weighted imaging (DWI) or fluid attenuated inversion recovery (FLAIR)

AND

Without routine investigations indicating an alternative diagnosis.

Possible

Progressive dementia; and at least two out of these four clinical features:

• Myoclonus
• Visual or cerebellar signs
• Pyramidal/extrapyramidal signs
• Akinteic mutism

AND

The absence of a positive result for any of the four tests above that would classify a case as “probable”

AND

Duration of illness less than two years

AND

Without routine investigations indicating an alternative diagnosis.

Iatrogenic CJD

About 1 percent of Classic CJD cases are iatrogenic, meaning spread through healthcare products or in a healthcare setting.

To meet the definition for an iatrogenic case, the case must meet the following criteria:

Progressive cerebellar syndrome in a recipient of human cadaveric-derived pituitary hormone

OR

Sporadic CJD with a recognized exposure risk, such as neurosurgery with dura mater implantation.

Familial CJD

An estimated 5-15 percent of classic CJD cases are familial, due to an inherited gene mutation. To meet the case definition for familial CJD, a case must:

Have definite or probable CJD and definite or probable CJD in a first-degree relative

AND/OR

Neuropsychiatric disorder and disease-specific PrP gene mutation.