CJD belongs to family of human transmissible spongiform encephalopathy. This is a rare and fatal degenerative brain disease caused by an abnormal prion protein. 

Incidence: 1 case per million per year

Sporadic: Most common type. Cause is uncertain but likely due to spontaneous 

mutation resulting in abnormal prion protein

Genetic: Autosomal dominant; commonest mutation - E200K mutation in PRNP 

gene on chromosome 20

Iatrogenic: Transmission is through infected human growth hormone, corneal 

grafts, dural grafts, intracranial EEG electrodes

New variant: Human form of bovine spongiform encephalopathy; acquired by 

consumption of infected beef

Incoordination, pyramidal/extrapyramidal/cerebellar signs, myoclonus, blindness, coma

Early Stage: Lethargy, headache, insomnia, poor appetite and depression. 

Later Stage: Impaired memory, personality changes, visual hallucinations, impaired 

speech/swallow, dementia.

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 only performed post mortem,

spongiform changes with vacuolation, neuronal loss and gliosis evident.

No curative treatment available yet

Symptoms relentlessly progress resulting in death. 

Sporadic CJD patients have a prognosis of about 4-6 months.