Creutzfeldt-Jacob Disease
Alternate Names : New Variant CJD - "the Human Form of Mad Cow Disease", Transmissible Spongiform Encephalopathy
Definition Creutzfeldt-Jacob disease is a disorder involving rapid decrease of mental function and movement. These are abnormalities believed to be caused by damage done to the brain by a protein called a prion. This protein folds abnormally, and seems to encourage other proteins to become similarly misshapen, affecting their ability to function.
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Overview, Causes, & Risk Factors
Creutzfeldt-Jakob disease can occur sporadically (for no known reason), as a result of exposure to contaminated products. Rarely, it can be genetically inherited. The disorder itself is rare, occurring in about 1 out of 1 million people. It usually first appears in midlife, beginning between ages 20 and 70, with average age at onset of symptoms in the late 50s.
However, some cases have occurred in adolescents who have received growth hormone derived from the pituitary glands of cadavers (dead bodies). Prions cannot be destroyed by ordinary disinfection techniques used to prevent transmission of viruses and bacteria. As a result, the hormone remains contaminated, and this exposure is believed to be responsible for the early onset of the disease in these people.
Cadaver-derived growth hormone has been replaced by synthetically manufactured growth hormone, so this source of contagion is no longer a problem. Other cases have occurred when people were given corneal transplants from infected donors, and from contaminated electrodes that were used in brain surgery (before it was known how to properly disinfect instruments).
More recently, a type of disease called new variant Creutzfeldt-Jakob disease has emerged. It was first reported in the U.K. in people who had eaten meat from cows who were fed infected bone meal.
The version of the disease found in cows has come to be known as "mad cow disease", and nvCJD has been called "the human form of mad cow disease," in news accounts. This disease tends to affect younger people and has early psychiatric manifestations. There have not been any cases of nvCJD reported in the U.S.
Once symptoms appear, the disorder progresses rapidly and may be confused with other types of dementia -- like Alzheimer's disease. Both forms of CJD, however, are distinguished by extremely rapid progression from onset of symptoms to disability and death. There may be a familial tendency to acquire the disorder. Early symptoms include personality changes and difficulty with coordination.
Creutzfeldt-Jacob disease may be related to several other diseases also thought to be caused by prions, including kuru (seen in New Guinea women who ate the brains of deceased relatives as part of a funerary ritual), scrapie (found in sheep), bovine spongiform encephalitis -- "mad cow disease," and other rare human diseases, such as Gerstmann-Straussler-Scheinker disease and fatal familial insomnia.
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