Creutzfeldt-Jakob disease
DEFINITION
Creutzfeldt-Jakob (KROITS-felt YAH-kobe) disease is a degenerative brain disorder that leads to dementia and, ultimately, death. Symptoms of Creutzfeldt-Jakob disease (CJD) sometimes resemble those of other dementia-like brain disorders, such as Alzheimer’s, but Creutzfeldt-Jakob disease usually progresses much more rapidly.
Creutzfeldt-Jakob disease captured public attention in the 1990s when some people in the United Kingdom developed a form of the disease — variant CJD (vCJD) — after eating meat from diseased cattle. However, “classic” Creutzfeldt-Jakob disease has not been linked to contaminated beef.
Although serious, CJD is rare, and vCJD is the least common form. Worldwide, there is an estimated one case of Creutzfeldt-Jakob disease diagnosed per million people each year, most commonly in older adults.
CAUSES
Creutzfeldt-Jakob disease and its variants belong to a broad group of human and animal diseases known as transmissible spongiform encephalopathies (TSEs). The name derives from the spongy holes, visible under a microscope, that develop in affected brain tissue.
The cause of Creutzfeldt-Jakob disease and other TSEs appears to be abnormal versions of a kind of protein called a prion. Normally, these proteins are harmless, but when they’re misshapen they become infectious and can wreak havoc on normal biological processes.
How CJD is transmitted
The risk of CJD is low. The disease can’t be transmitted through coughing or sneezing, touching, or sexual contact. The three ways it develops are:
- Sporadically. Most people with classic CJD develop the disease for no apparent reason. CJD that occurs without explanation is termed spontaneous CJD or sporadic CJD and accounts for the majority of cases.
- By inheritance. In the United States, about 5 to 10 percent of people with CJD have a family history of the disease or test positive for a genetic mutation associated with CJD. This type is referred to as familial CJD.
- By contamination. A small number of people have developed CJD after being exposed to infected human tissue during a medical procedure, such as a cornea or skin transplant. Also, because standard sterilization methods do not destroy abnormal prions, a few people have developed CJD after undergoing brain surgery with contaminated instruments. Cases of CJD related to medical procedures are referred to as iatrogenic CJD. Variant CJD is linked primarily to eating beef infected with bovine spongiform encephalopathy (BSE), the medical term for mad cow disease.
SYMPTOMS
Creutzfeldt-Jakob disease is marked by rapid mental deterioration, usually within a few months. Initial signs and symptoms of CJD typically include:
- Personality changes
- Anxiety
- Depression
- Memory loss
- Impaired thinking
- Blurred vision
- Insomnia
- Difficulty speaking
- Difficulty swallowing
- Sudden, jerky movements
As the disease progresses, mental symptoms worsen. Most people eventually lapse into a coma. Heart failure, respiratory failure, pneumonia or other infections are generally the cause of death. The disease usually runs its course in about seven months, although a few people may live up to one or two years after diagnosis.
In people with the rarer vCJD, psychiatric symptoms may be more prominent in the beginning, with dementia — the loss of the ability to think, reason and remember — developing later in the course of the illness. In addition, this variant affects people at a younger age than classic CJD does, and appears to have a slightly longer duration — 12 to 14 months.
