Creutzfeldt-Jakob Disease
Creutzfeldt-Jakob disease (CJD) is a rare form of progressive dementia characterized by loss of nerve cells and degeneration of nerve cell membrances leading to the production of small holes in the brain.
CJD usually has a rapid onset and decline. Early symptoms include lapses in memory, mood swings similar to depression, lack of interest and social withdrawal. The person may become unsteady on his/her feet. Later symptoms may include blurred vision, sudden jerking movements and rigidity in the limbs. The person may experiences slurred speech and have difficulty swallowing. Eventually, movement and speech are lost.
Both men and women can be affected by CJD. The usual age of onset is 45-75 years. In Canada, all cases of CJD are reported to the National CJD Surveillance Unit in Ottawa, which has been gathering information on the disease since 1997.
What are the types of Creutzfeldt-Jakob Disease?
There are four forms of the disease:
Sporadic CJD. "Sporadic" means occurring here and there in the general population. There are no obvious risk factors. Sporadic CJD is the most common form accounting for 85-90% of all cases. The cause of transmission is unknown. It usually affects people between age 45-75, with the peak age of onset being 60-65. The incidence of sporadic CJD in Canada is around one per million, or 30 new cases every year.
Familial CJD. "Familial" means occurring in families; some families have a mutation in the prion protein gene (PrP gene). Familial CJD accounts for 15 percent of all cases of CJD. IT has an early onset, around age 52. Other mutations of the PrP gene have been identified and are associated with two, rare brain diseases which resemble familial CJD. These are Gertsmann-Straussler-Scheiner disease (GSS) and fatal familial insomnia (FFI). GSS usually starts with unsteadiness in walking and progresses to dementia. The main symptom of FFI is a progressive and untreatable form on insomnia.
Transmissible CJD. This form (also known as "iatrogenic CJD") is caused by direct contact with infected tissue from someone with the disease. This form is the rarest, accounting for 1% of all cases. Transmission of CJD has occurred from certain medical procedures such as brain operations performed with instruments which were previously used on someone with CJD, corneal transplants, and grafts of dura mater, the membrance that covers the brain and is used in various kinds of surgery. CJD has also been transmitted by human growth hormone prepared from human pituitary glands. Today the growth hormone is made synthetically, greatly reducing the risk of this type of CJD. Presently, researchers are unsure of the role of blood transfusions in the transmission of the disease, but the consensus is that it represents a theoretical risk.
Variant CJD. "Variant" CJD is linked to eating contaminated beef products. Variant CJD was first diagnosed in the United Kingdom in 1996. It is believed to be caused by exposure to contaminated meat from cattle suffering from Bovine Spongiform Encephalopathy (BSE or "Mad Cow" disease). Most of the people affected by this variant are young, with a mean age of around 28. It should be noted, however, that the age of onset is wide, ranging from 12 to 74 years of age.
How is Creutzfeldt-Jakob Disease transmitted?
CJD is unique because it can be inherited or transmitted. The infectious agent is believed to be an abnormal form of the prion protein (PrP). However, CJD is not infectious in the usual way - like colds of flu, or by skin contact. It is transmitted only though contact with, or dietary exposure to, CJD brain matter. There are no special risks in caring for a person with CJD. The agent has been compared to a "slow virus" because there is long inclubation period (1-30 years) before signs of the disease appear. Once symptoms are visible, decline is usually rapid. Depending upon the type of CJD, the length of the illness is usually one year, but can range from months to several years after onset.
Currently there is no way to slow the progression of the disease. Some medication can help relieve jerking movements and unsteadiness.
More information, contact the Alzheimer Society or visit the following websites:
The Creutzfeldt-Jakob Disease Surveillance System in Canada Study Team
www.hc-sc.gc.ca/pphp-dgspsp/hcai-iamss/cjd-mcj/index.html
Canadian Food Inspection Agency, BSE Fact Sheet or Web site:
www.inspection.gc.ca/english/anima/heasan/disemala/bseesb/bseesbfse.shtml
CJD Support Network (UK)
www.cjdsupport.net
U.K Web Site
www.cjd.ed.ac.uk
European Collaborative Study Gruop of CJD
www.eurocjd.ed.ac.uk
The information contained on this website is not intended to replace clincial diagnosis by a health professional.
SOURCE: Research - Related Dementia-Creutzfeldt Jakob Disease - Alzheimer Society of Canada
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