Creutzfeldt-Jakob Disease is a rapidly progressive degenerative disease of the nervous system that can be transmitted by blood or tissues between human beings.
It is estimated that 50-100 cases occur each year in the UK, with an equal sex ratio and onset typically occurring between the ages of 40 and 60.
The disease is caused by the accumulation of an abnormal prion protein in the brain, which is encoded on chromosome 20. Those with the E4 allele of apolipoprotein are at a higher risk of developing the disease, and the familial form, known as Gerstmann-Straussler-Scheinker, accounts for 10% of patients and principally affects the cerebellum. It is also autosomal dominant.
Clinical features of the disease can include personality changes, seizures, intellectual deterioration, and neurological deficits such as cerebellar ataxia, spasticity, extrapyramidal signs, and myoclonus sensitivity to noise or touch. In new-variant CJD (nvCJD), initial psychiatric symptoms are followed by a cerebellar syndrome leading to memory failure and akinetic mutism. There are four forms of the disease: subacute spongiform encephalopathy (SSE 1), which is rapidly fatal, SSE 2 (Heidenhaim’s – blindness and dementia), thalamic form, and ataxic form.
Diagnosis can be confirmed by abnormal EEG results, which are present in 90% of patients, low voltage with bi/triphasic discharges, and repetitive complexes that coincide with the myoclonus. Atrophy may be apparent in the later stages with CT or MRI, and the CSF protein is sometimes moderately elevated.
The prognosis for Creutzfeldt-Jakob Disease is poor, with the disease progressing rapidly over the course of 1-2 years.