Alternate Names: Jakob-Creutzfeldt Disease, Jakobs Disease, Subacute Spongiform Encephalopathy, Variant (V-CJD) Bovine Spongiform Encephalopathy (BSE), Fatal Familial Insomnia (FFI), Gerstmann-Straussler-Scheinker (GSS) Disease, Prion disease, Mad Cow Disease
CJD belongs to a group of human and animal diseases known as transmissible spongiform encephalopathies (TSE) or prion diseases. Spongiform refers to the characteristic appearance of infected brains, which become filled with holes until they resemble sponges under a microscope.
Typically, onset of symptoms occurs at about age 60 and runs a rapid course.
There are four major categories of CJD:
Sporadic CJD is the most common form of the disease. It accounts for 85% of cases. The cause of sporadic CJD is unknown, but it is believed that a normal cellular protein undergoes a spontaneous change in conformation (prion protein) that results in the disease. This form of the disease is believed to be spontaneous and not the result of an infection.
Hereditary or familial CJD is a very uncommon disease and the consequence of a mutation in the gene that encodes the prion protein. About 5 to 10 percent of cases of CJD in the United States are hereditary.
Acquired or Iatrogenic CJD is also very rare accounting for less than 1% of cases. It results from the accidental transmission during the course of medical interventions. Examples include transmission in cases of corneal transplantation, dural grafts, or treatment with Human Growth Hormone isolated from cadaveric pituitary glands.
Variant CJD was first reported in 1996. It is believed to be the result of eating meat from cattle with bovine spongiform encephalopathy (BSE or mad cow disease). In contrast with sporadic CJD which affects older people, the variant form primarily affects young subjects (i.e., in the late 20s) and may have a longer course, between one and two years.
The diagnosis of CJD is suspected when there are typical clinical symptoms such as rapidly progressing dementia with myoclonus (twitching). Currently, there is no single diagnostic test for CJD except for brain biopsy. The first concern is to rule out treatable forms of dementia such as encephalitis or chronic meningitis.
The following investigations can be performed to support the diagnosis:
Brain biopsy is the definite diagnostic test, but is performed only in selected cases because the procedure may be dangerous to the individual. Since a correct diagnosis of CJD does not help the individual, brain biopsy is discouraged unless it is needed to rule out a treatable disorder.
There is no treatment that can cure or control CJD.
Current treatment is aimed at alleviating symptoms and making the patient as comfortable as possible. Opiate drugs can help relieve pain, and the drugs clonazepam and sodium valproate may help relieve involuntary muscle jerks.
About 90 percent of patients die within 1 year.
In the early stages of disease, patients may have failing memory, behavioral changes, lack of coordination and visual disturbances.
As the illness progresses, mental deterioration becomes pronounced and involuntary movements, blindness, weakness of extremities, and coma may occur.