Creutzfeldt-Jakob disease, a transmissible, rapidly progressive dementia of unknown etiology, mimics Alzheimer\u27s disease, presents in middle life, and affects many central nervous system structures. The disease progresses in three distinct stages, culminating in death. Its occurrence is sporadic and its distribution worldwide. Pathological changes are varied, but spongy degeneration of the neuropil is classic. Research on scrapie, the animal model of Creutzfeldt-Jakob disease, has demonstrated that this unconventional, slow disease is transmitted via a small (less than 50,000 mW) particle, which is composed principally of protein. How this infectious particle, variably named prion, virino, or slow virus, invokes disease or is transmitted is unclear. The agent does not evoke a host immune response, nor does it appear to contain nucleic acid. No treatment has proven successful, although amantadine has been partially effective in some cases. Decreased brain concentrations of dopamine and norepinephrine are associated pharmacological abnormalities
