Medical Edge Newspaper Column

CJD an Uncommon, Degenerative Brain Disease

March 9, 2012
Dear Mayo Clinic:
Recently I read of research done on Creutzfeldt-Jakob disease that indicated a correlation between this disease and people who previously had a major surgical procedure. Is this true? What can you tell me about how this disease develops?

Answer:
No research to date has shown that just having a major surgical procedure raises a person's future risk of developing Creutzfeldt-Jakob disease (CJD). A small number of people have developed CJD after being exposed to infected human tissue or contaminated instruments during a medical procedure. But that is very rare.

CJD is an uncommon degenerative brain disorder that leads to dementia and, eventually, death. The disease, which has no known cure, often progresses quickly and is characterized by rapid mental and physical deterioration that takes place over several weeks or months. It belongs to a group of human and animal diseases known as transmissible spongiform encephalopathies. The name comes from the microscopic spongy holes, called spongiform change, that appear in brain tissue affected by the disease.

Creutzfeldt-Jakob disease is the result of abnormal folding of a human protein called a prion, which is found within nerve cells. The normal form of this protein is harmless. But when misfolded, it becomes infectious and can destroy nerve cells in the brain. The space in and around the dying nerve cells is the spongiform change.

The brain cell death leads to a variety of symptoms. CJD often affects cognitive skills, including memory, thinking and language. It can also cause motor problems, particularly a rapid, jerking movement known as myoclonus, as well as muscle rigidity and loss of balance. These symptoms often appear and progress rapidly.

As the disease progresses, most people with CJD eventually lapse into a coma. Heart failure, respiratory failure, pneumonia or another infection are usually the immediate cause of death. The disease usually runs its course in two to three months, although a few people may live up to one or two years after diagnosis.

Creutzfeldt-Jakob disease has several forms. A related disease gained public attention in the 1990s when some people in the United Kingdom developed a type called variant CJD (vCJD) after eating meat from cattle infected with bovine spongiform encephalopathy — the medical term for mad cow disease. However, other forms of CJD have not been linked to contaminated beef.

The most common form is sporadic CJD, which people develop for no known reason. Presently, no clear environmental or other risk factors are associated with sporadic CJD. Worldwide, there is only about one case of sporadic Creutzfeldt-Jakob disease diagnosed per million people each year. Another form is familial Creutzfeldt-Jakob disease, which accounts for about 10 percent of people who have the disorder. In familial CJD, people have a family history of the disease or a genetic mutation associated with prion formation.

Finally, there is a form known as iatrogenic CJD that occurs when the disease is transmitted through infected human tissue or contaminated medical instruments. This transmission takes place because the prion protein is not inactivated by the normal procedures used to sterilize medical instruments. Iatrogenic CJD is very rare. It usually happens via a medical procedure, such as a corneal transplant or brain surgery with infected materials, which brings protein from a person who has the disease to an unaffected recipient. Because CJD does not involve a virus or bacteria, it is not transmitted through coughing or sneezing, touching or sexual contact.

Although a very serious disease, CJD is rare, with iatrogenic CJD being the least common form of this rare disorder.

— Allen Aksamit, M.D., Neurology, Mayo Clinic, Rochester, Minn.