Overview
Definition
A rapidly progressive, fatal transmissible spongiform encephalopathy caused by prions, characterized by dementia, myoclonus, and ataxia.
Epidemiology
Incidence ~1 per million annually. Most cases are sporadic (sCJD), but can be familial or acquired (variant CJD).
Etiology & Risk Factors
- Conformational change of normal prion protein (PrPC) into abnormal, protease-resistant form (PrPSc)
Clinical Symptoms
- Rapidly progressive dementia
- Startle myoclonus (sudden muscle jerks triggered by sound/touch)
- Cerebellar ataxia
- Visual disturbances / Cortical blindness
- Akinetic mutism in late stages
Clinical Approach
Diagnosis
- EEG showing periodic sharp wave complexes
- MRI showing hyperintensity in caudate/putamen ('hockey stick sign') or cortical ribboning
- CSF assay showing 14-3-3 protein or RT-QuIC (highly specific)
Management
- Palliative care (no curative treatment exists; fatal within 1 year of onset)
Complications
- Aspiration pneumonia
- Severe contractures
- Coma and death