What is It?
Creutzfeldt-Jakob disease (CJD) is a form of brain damage that leads to a rapid decrease of mental function and movement.
Causes, incidence, and risk factors
CJD is thought to be caused by a protein called a prion. A prion causes normal proteins to fold abnormally. This affects the other proteins’ ability to function.
There are several types of CJD. The disorder is very rare, occurring in about 1 out of 1 million people. It usually first appears between ages 20 and 70. Symptoms usually start in the late 50s.
CJD can be grouped into two types: classic or new variant disease.
The classic types of CJD are:
- Sporadic CJD makes up most cases. It occurs for no known reason. The average age at which it starts is 65.
- Familial CJD occurs when a person inherits the abnormal prion from a parent (inherited CJD is rare)
Classic CJD is not related to mad cow disease (bovine spongiform encephalitis).
However, variant CJD (vCJD) is a form of the disease that is related to mad cow disease. The infection that causes the disease in cows is believed to be the same one that causes vCJD in humans.
Variant CJD accounts for less than 1% of cases, and it tends to affect younger people. However, fewer than 200 people worldwide have had this disease.
Variant CJD can be caused by exposure to contaminated products. Other vCJD cases have occurred when people were given corneal transplants, other tissues, or blood transfusions from infected donors. It may also have been caused by contaminated electrodes used in brain surgery (before instruments started to be properly disinfected).
There have not been any cases of vCJD reported in the U.S.
CJD may be related to several other diseases caused by prions, including:
- Chronic wasting disease (found in deer)
- Kuru (seen in New Guinea women who ate the brains of dead relatives as part of a funeral ritual)
- Scrapie (found in sheep)
- Other rare human diseases, such as Gerstmann-Straussler-Scheinker disease and fatal familial insomnia
- Blurred vision (sometimes)
- Changes in gait (walking)
- Confusion, disorientation
- Dementia that occurs over a few weeks or months
- Lack of coordination (for example, stumbling and falling)
- Muscle stiffness
- Muscle twitching
- Myoclonic jerks or seizures
- Nervous, jumpy feelings
- Personality changes
- Speech impairment
CJD is rarely confused with other types of dementia (such as Alzheimer’s disease) because in CJD, the symptoms get worse much more quickly. Both forms of CJD are different than dementia because the symptoms progress quickly to disability and death.
Signs and tests
Early in the disease, a nervous system and mental examination will show memory problems and changes in other mental functions. Later in the disease, a motor system examination may show:
- Abnormal reflexes or increased normal reflex responses
- Increase in muscle tone
- Muscle twitching and spasms
- Strong startle response
- Weakness and loss of muscle tissue (muscle wasting)
There is loss of coordination and changes in the cerebellum, the area of the brain that controls coordination (cerebellar ataxia). An eye examination shows areas of blindness that the person may not notice.
Tests used to diagnose this condition may include:
- Blood tests to rule out other forms of dementia and to look for markers that sometimes occur with the disease
- CT scan of the brain
- Electroencephalogram (EEG)
- MRI of the brain
- Spinal tap to test for a protein called 14-3-3
The disease can only be confirmed with a brain biopsy or autopsy.
There is no known cure for this condition. Interleukins and other medications may help slow the disease. The person may need care early in the disease. Medications may be needed to control aggressive behaviors.
Providing a safe environment, controlling aggressive or agitated behavior, and meeting the person’s needs may require monitoring and assistance in the home or in a care facility. Family counseling may help the family cope with the changes needed for home care.
Visiting nurses or aides, volunteer services, homemakers, adult protective services, and other community resources may help care for the person with CJD.
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