Creutzfeldt Jakob disease
Related Subjects:
|Dementias
|Gerstmann-Straussler-Scheinker Syndrome (GSS)
|Fatal Familial Insomnia (FFI)
|Creutzfeldt Jakob disease (CJD)
|Variant Creutzfeldt Jakob disease (vCJD)
|Kuru
🧾 About
- The classical form of Creutzfeldt-Jakob Disease (CJD) is a prion disease unrelated to bovine spongiform encephalopathy (BSE).
- It affects mainly older adults and follows a very aggressive course compared with the variant form.
- Caused by misfolded prion proteins (PrPSc) that induce abnormal folding of normal host proteins (PrPC), leading to neurodegeneration.
🔎 Types
- Sporadic CJD (sCJD): Most common form (~85-90%).
- Familial CJD: 5–15%, autosomal dominant inheritance (mutations in PRNP gene).
- Iatrogenic CJD: Transmission through contaminated medical procedures (pituitary extracts, corneal transplants, dura mater grafts).
- Variant CJD (vCJD): Linked to BSE (“mad cow disease”), affecting younger patients.
📋 Diagnostic Criteria
- Definite: Neuropathology, immunocytochemistry, or Western blot confirming prion protein (PrPSc).
- Probable:
- Positive RT-QuIC (real-time quaking-induced conversion) in CSF or tissue OR
- Rapidly progressive dementia + ≥2 of:
- Myoclonus
- Visual/cerebellar disturbance
- Pyramidal or extrapyramidal features
- Akinetic mutism
- AND one of:
- EEG with periodic sharp-wave complexes
- CSF 14-3-3 protein (within 2 years of onset)
- MRI: High signal in caudate/putamen or cortical regions on DWI/FLAIR
- Possible: Dementia + ≥2 clinical features listed above, without confirmatory investigations.
🧠 Diagram
⚖️ Classic vs Variant CJD
| Characteristic | Classic CJD | Variant CJD |
|---|
| Median age at death | 68 years | 28 years |
| Duration of illness | 4–5 months | 13–14 months |
| Clinical onset | Dementia; early neurologic signs | Psychiatric/behavioral symptoms, painful dysesthesias |
| EEG | Periodic sharp waves often present | Often absent |
| MRI | Basal ganglia hyperintensity | Pulvinar sign (>75%) |
| Neuropathology | Spongiform change ± rare plaques | Florid plaques common |
| Lymphoid tissue prions | Not detected | Readily detected |
🩺 Clinical Presentation
- Rapidly progressive dementia with myoclonus (classic triad).
- Other features: ataxia, visual disturbance, behavioral change, extrapyramidal signs.
- Variant CJD: Younger patients, psychiatric prodrome, delayed dementia.
🧪 Investigations
- EEG: Periodic triphasic sharp-wave complexes (seen in ~2/3 of sCJD).
- MRI: DWI/FLAIR hyperintensity in caudate, putamen, or cortical ribboning.
- CSF: 14-3-3 protein (non-specific, can be positive in stroke/MS); RT-QuIC is more specific.
- Brain biopsy/post-mortem: Gold standard – spongiform change, neuronal loss, and PrPSc deposition.
💊 Management
- No curative treatment – management is supportive.
- Report suspected cases to the CJD surveillance unit (UK requirement).
- Genetic counseling for familial cases.
- Emphasis on infection control (prion proteins resist sterilisation).
