Creutzfeldt-Jakob disease (CJD) is an infectious disease that causes the brain to degenerate. The hallmark of this brain disease is an inability to think clearly and take care of oneself. Over time, the disease causes an increasing difficulty with memory, personality changes, and dementia. CJD progresses rapidly and can be fatal.
According to the World Health Organization (WHO), CJD occurs all over the world, but it is not very common. Only one person per million will get this illness (WHO, 2012). In the United States, only 200 cases per year are diagnosed, according to the National Institutes of Health (NIH, 2011).
There is a connection between CJD and mad cow disease. Mad cow disease (also known as bovine spongiform encephalopathy, or BSE), is a well-known brain disease. BSE affected cattle in the United Kingdom primarily in the 1990s and early 2000s. The connection? One form of CJD, variant Creutzfeldt-Jakob disease (vCJD), first appeared in humans in 1996 about a decade after mad cow first appeared. The Centers for Disease Control and Prevention states that scientists believe that this decade was the exact amount of time needed for mad cow to mutate into a form that could affect humans (CDC, 2012).
CJD is caused by an infectious agent called a prion. Prions are a type of small protein normally found in the tissues of many mammals. In prion disease, these proteins are abnormally folded, form clumps, and destroy nerve cells. When they infect a mammal, the normal proteins start to take on the incorrect structure as well. This causes disease.
The prions involved in CJD cause brain injuries by clumping into abnormal plaques called amyloids. These plaques disrupt the structure of the brain. CJD and BSE are called “spongiform” encephalopathies because on brain images, the brain appears to contain holes where cells have died—resembling a sponge.
The two main types of human CJD are classic and variant CJD.
Classic CJD can develop anytime between the ages of 20 and 70. However, it most commonly occurs in the late 50s. Classic CJD has no connection to mad cow disease. The two types of classic CJD are sporadic and inherited.
Sporadic CJD occurs when there is a spontaneous mutation of normal proteins to the abnormal prion type. According to the National Institute of Neurological Disorders and Stroke, 85 percent of CJD cases are sporadic (NINDS, 2003). Sporadic CJD is most common in people over the age of 65.
Inherited CJD is rare. It occurs when you inherit a gene associated with prion disease from a parent. Inherited CJD is dominant. That means you only need to inherit the mutated gene from one parent. It may also be possible to inherit the protein directly. People with inherited CJD often have family members with the disease.
Variant CJD or vCJD occurs in both animals and humans. When it appears in cattle, it is referred to as mad cow disease, or BSE (bovine spongiform encephalopathy). According to the Mayo Clinic, vCJD affects mostly young people in their 20s (Mayo Clinic, 2010).
Humans become infected with vCJD by eating meat that is contaminated by infectious prions. However, your risk of eating infected meat is very low. You could also become infected after receiving blood or transplanted tissues (such as a cornea) from an infected donor. The disease can also be transmitted by surgical instruments that have not been properly sterilized.
For all the press on mad cow disease, vCJD is very rare. From October 1996 to March 2011, only 175 cases were reported worldwide (WHO, 2012). Less than one percent of people with CJD have the variant type.
The risk of classic CJD increases with age. You cannot get CJD from casual exposure to people who are infected.
You can get CJD from exposure to infected bodily fluids. Therefore, caregivers of the sick should take extra precautions. The NIH recommends the following precautions if you are a caregiver for a person with CJD or variant CJD:
Difficulty swallowing is one of the most dangerous symptoms of CJD. This increases your risk of aspiration pneumonia, which is a major cause of death. Being disoriented or having problems walking are also dangerous. They increase your risk of falls and other types of accidents. Other symptoms of CJD include:
- dementia: a decreasing ability to think, reason, communicate, and maintain self-care
- ataxia: a loss of balance or coordination
- changes in personality and behavior: these are more common in variant CJD
- confusion or disorientation
- muscle twitching and stiffness
- difficulty talking
Symptoms of CJD will get worse until you lapse into a coma. The most frequent causes of death for CJD patients are pneumonia and other infections.
The dementia of variant and classic CJD causes your mind and body to deteriorate quickly. This is very different from Alzheimer’s-associated dementia, which progresses slowly. Sadly, ninety percent of people with classic CJD die within a year. People with variant CJD tend to have a longer clinical course than those with classic CJD.
The diagnosis of CJD begins with a complete history, physical examination, and neurological evaluation. The rapid progression of symptoms distinguishes CJD from other causes of dementia. A number of tests can also be used to establish the diagnosis:
Lumbar Puncture (With a Single-Use Kit)
This test uses a thin needle to puncture the lining of your spinal cord to obtain spinal fluid. Spinal fluid may test positive for a protein called 14-3-3.
This test uses scalp electrodes to examine brain waves. Brain waves in CJD may show sharp spikes.
CAT Scan of the Brain
CAT scans obtain detailed X-ray images that help doctors determine the extent of damage to the brain.
This test obtains information that is similar to a CAT scan. It uses magnetic fields instead of X-rays.
Blood tests can identify and rule out problems like hypothyroidism and syphilis, which can also cause dementia.
There is no known cure or effective treatment for CJD. However, medications can be used to treat some of the mental changes and personality abnormalities that occur. Treatment is usually focused on making patients comfortable and to help them function safely in their environment.