Also known as “Mad Cow Disease.”
Creutzfeldt-Jakob disease (CJD) is one of a group of progressive neurological diseases called transmissible spongiform encephalopathies (TSEs). TSEs, which can affect humans and animals, cause brain tissue to become so filled with holes that it resembles a sponge upon microscopic examination.
Transmissible spongiform encephalopathies are also called prion diseases. Prions are proteins that lack nucleic acids (e.g., DNA, RNA), which are complex compounds present in all other living cells. Prions occur in a normal, harmless form, and in an infectious form, which causes disease. Prion diseases occur when infectious prions bind to normal proteins in the central nervous system and cause abnormal cell conformation.
Prion diseases can occur in animals that consume prion-contaminated food. These diseases include scrapie, which occurs in sheep and goats, and bovine spongiform encephalopathy (BSE), which occurs in cows and is also called "mad cow disease."
Transmission of prion diseases from one species to another is not fully understood, but it can occur. Variant Creutzfeldt-Jakob disease (vCJD) is an acquired disease that develops in people who ingest beef from cattle with BSE. In Europe, recent outbreaks of mad cow disease have resulted in several cases of vCJD in young adults.
There are three general types of Creutzfeldt-Jakob disease: sporadic, familial, and acquired (e.g., vCJD). Sporadic CJD (sCJD) occurs with no known risk factors and is the most common type. It accounts for at least 85% of cases.
Familial Creutzfeldt-Jakob disease (fCJD) occurs as a result of an inherited genetic abnormality. This type accounts for 5-15% of cases and is similar to other inherited neurological diseases such as Gerstmann-Straussler-Sheinker disease (GSS) and fatal familial insomnia (FFI).
Rarely, CJD is acquired as a result of a medical procedure or treatment (e.g., organ or tissue transplant, graft, human growth hormone [hGH] therapy) that exposes the central nervous system to prion-contaminated tissue or medical instruments. This type accounts for less than 1% of cases and is called iatrogenic Creutzfeldt-Jakob disease (iCJD).
Creutzfeldt-Jakob disease affects on average about one person in a million worldwide each year. Now that an expert British committee has tentatively linked it to mad cow disease, a question is raised: how many, if any, of these cases are caused by something in the diet or environment.
The natural history of the mysterious malady may shed light on its cause, and may also help clarify the nature of other brain-destroying diseases like Alzheimer's
, to which Creutzfeldt-Jacob disease seems related by symptoms and pathology. With both diseases, waxy deposits known as amyloid plaques are seen under the microscope in stricken nerve cells.
Until now, the best known of the spongiform diseases has been kuru, believed to result from ritualistic cannibalism among the Fore group in the highlands of Papua-New Guinea. It has largely disappeared now that such practices have ceased.
Creutzfeldt-Jakob disease usually strikes people in their 50's and 60's, after taking years or even decades to develop. But once symptoms begin, the course is swift and relentless. Destruction of brain cells impairs an individual's ability to think, see, speak and move. Muscles go into spasm, becoming rigid and jerky. Balance is lost. The dementia that develops mimics Alzheimer's disease, a related disorder that is not classified as a spongiform disease.
Doctors have found Creutzfeldt-Jakob disease everywhere in the world they have looked. Among its most famous victims was George Balanchine, the choreographer, who died in New York City in 1983.
Additional symptoms that may be associated with this disease:
- Blurred vision (sometimes).
- Changes in gait (walking).
- Lack of coordination (for example, stumbling and falling).
- Muscle twitching.
- Muscle stiffness.
- Myoclonic jerks or seizures.
- Nervous, jumpy feelings.
- Personality changes.
- Profound confusion, disorientation.
- Rapidly developing delirium or dementia.
- Speech impairment.
Causes and Risk factors:
No one is sure what causes mad cow disease. One theory is that the disease is caused by a change in the shape of some of the proteins found in animal cells. This change may be caused by other abnormal proteins called prions. In affected cows, the abnormal proteins (prions) are found in the brain, spinal cord, and small intestine. There is no evidence that these abnormal proteins are found in muscle meat (such as steak) or in milk. Another theory is that mad cow disease is caused by a virus that causes the proteins to change and become abnormal (prions).
Sporadic Creutzfeldt-Jakob diseasedevelops when normal prions spontaneously change into infectious prions and then alter other cells. Infectious prions stick together, forming fibers and plaques that accumulate in brain tissue. These fibers and plaques can be detected years before CJD symptoms develop.
Familial Creutzfeldt-Jakob diseaseis caused by a genetic abnormality (mutation) that results in infectious prion formation. Several types of prion gene mutations have been identified, and the specific type affects how often the disease occurs within a family and the severity of the symptoms. Other risk factors play a role in the development of the disease because not all people with the genetic abnormality will develop CJD.
People who consume contaminated beef may be at increased risk for developing an acquired form of Creutzfeldt-Jakob disease called variant Creutzfeldt-Jakob disease (vCJD). Although this risk has not been proven, there is a strong similarity between the prions that cause mad cow disease (BSE) and vCJD. In Europe, several cases of the disease have occurred in younger than average patients following an outbreak of BSE.
Rarely, iatrogenic C reutzfeldt-Jakob disease(iCJD) is acquired as a result of a medical procedure or treatment (e.g., organ or tissue transplant, graft, human growth hormone [hGH] therapy) that exposes the central nervous system to prion-contaminated tissue or medical instruments.
Creutzfeldt-Jakob disease is not contagious, but direct or indirect contact with the blood, tissue, or spinal cord fluid of patients with the disease should be avoided to prevent transmission. Patients with suspected or confirmed CJD, and those at increased risk for the disease because of family history, should never donate blood, tissue, or organs.
Genetic analysis in people with iatrogenic and variant Creutzfeldt-Jakob disease suggest that inheriting identical copies of certain variants of the prion gene may predispose a person to developing CJD if exposed to contaminated tissue.
Age: Sporadic Creutzfeldt-Jakob disease tends to develop later in life, usually around the age of 60. Onset of familial CJD occurs only slightly earlier. On the other hand, vCJD has affected people at a much younger age, usually in their late 20s. This suggests that older adults may not be as susceptible to vCJD as children and young adults are.
Genetics: People with familial CJD have a genetic mutation that causes the disease. The disease is inherited in an autosomal dominant fashion, which means you only need to inherit one copy of the mutated gene, from either parent, to develop the disease. If you have the mutation, the chance of passing it on to your children is 50 percent.
Exposure to contaminated tissue: People who've received human growth hormone derived from human pituitary glands or who've had dura mater grafts may be at risk of iatrogenic Creutzfeldt-Jakob disease.
A neurological and motor system examination shows muscle twitching and spasm. There is a strong startle response. Muscle tone may be increased, or there may be weakness and muscle wasting (loss of muscle tissue). There may be abnormal reflexes or an increase in the response of normal reflexes.
There is loss of coordination related to visual-spatial perception changes 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 realize are present.
Tests used to diagnose this condition may include:
- Memory loss.
- Anxiety, stress, and tension.
- 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.
- Electroencephalogram (EEG): Using electrodes placed on your scalp, this test measures your brain's electrical activity. People with Creutzfeldt-Jakob disease and vCJD show a characteristically abnormal pattern.
- Magnetic resonance imaging (MRI): This technique uses radio waves and a magnetic field to create cross-sectional images of your head and body. It's especially useful in diagnosing brain disorders because of its high-resolution images of the brain's white matter and gray matter.
- Spinal fluid tests: Cerebral spinal fluid surrounds and cushions your brain and spinal cord. In a test called a lumbar puncture — popularly known as a spinal tap — doctors use a needle to withdraw a small amount of this fluid for testing. The presence of a particular protein in spinal fluid is often an indication of CJD or vCJD.
- Tonsil biopsy: Scientists have learned that tissue from the tonsils tends to harbor evidence of vCJD. Examination of a sample of tonsil tissue may help diagnose vCJD, but this method seems less reliable for other forms of CJD.
There is no known cure. Custodial care may be required early in the course of the disease. Medications may be needed to control aggressive behaviors. These include sedatives, antipsychotics, and others.
Providing a safe environment, controlling aggressive or agitated behavior, and meeting physiologic needs may require monitoring and assistance in the home or in an institutionalized setting. Family counseling may help in coping with the changes required for home care.
Visiting nurses or aides, volunteer services, homemakers, adult protective services, and other community resources may be helpful in caring for the person with Creutzfeldt-Jakob disease.
Behavior modification may be helpful, in some cases, for controlling unacceptable or dangerous behaviors. This consists of rewarding appropriate or positive behaviors and ignoring inappropriate behaviors (within the bounds of safety). Reality orientation, with repeated reinforcement of environmental and other cues, may help reduce disorientation.
Legal advice may be appropriate early in the course of the disorder to form advance directives, power of attorney, and other legal actions that may make it easier to make ethical decisions regarding the care of an individual with Creutzfeldt-Jakob disease.
Medicine and medications:
As was mentioned earlier, there is no treatment at this time for Creutzfeldt-Jakob disease. Medications can be given on a trial and error basis however; there has been no evidence of effectiveness. Sleeping pills may help your loved one if they are having difficulty sleeping at night. Sedatives may be needed if your loved one becomes aggressive or has violent hallucinations. Morphine can be used if breathing becomes extremely labored near the end of life. Morphine in small dose opens the airway making breathing easier for your loved one. Again, please check with your physician and/or care provider to obtain the right course of therapy for your loved one.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.