Pathology: CJDbelongs to family of human transmissible spongiform encephalopathy. This is arare and fatal degenerative brain disease caused by an abnormal prion protein.
Incidence:1 case per million per year
Aetiology: Sporadic:Most common type. Cause is uncertain but likely due to spontaneous
mutation resulting in abnormal prion protein
Genetic: Autosomal dominant; commonest mutation - E200Kmutation in PRNP
gene on chromosome 20
Iatrogenic: Transmission is through infected human growthhormone, corneal
grafts, dural grafts, intracranial EEG electrodes
New variant: Human form of bovine spongiform encephalopathy; acquiredby
consumption of infected beef
Symptoms: EarlyStage: Lethargy, headache, insomnia, poor appetite and depression.
Later Stage: Impaired memory, personality changes, visualhallucinations, impaired
speech/swallow, dementia.
Signs: Incoordination, pyramidal/extrapyramidal/cerebellarsigns, myoclonus, blindness, coma
Investigations: Imaging:MRI brain: may show changes in basal ganglia/thalamus
Lumbar Puncture: Presence of 14-3-3 and S100
EEG: Biphasic or triphasic periodic sharp waves
Biopsy: Brain biopsy is the gold standard test but onlyperformed post mortem,
spongiform changes withvacuolation, neuronal loss and gliosis evident.
Treatment: No curative treatment availableyet
Complications: Infection, heart failure, respiratory failure, death
Prognosis: Symptoms relentlessly progress resulting in death.
SporadicCJD patients have a prognosis of about 4-6 months.
VariantCJD patients with a prognosis of around 1 year
