CJD is caused by a protein called a prion. A prion causes normal proteins to fold abnormally. This affects other proteins' ability to function.
CJD is very rare. It occurs in about 1 out of every 1 million people.
There are several types of CJD. It can be grouped into sporadic, familial, or acquired types.
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 (this form of CJD is rare).
Acquired CJD includes variant CJD (vCJD), the form related to mad cow disease; and iatrogenic CJD, in which the disease is sometimes passed through a blood product transfusion, transplant, or contaminated surgical instruments.
Variant CJD is caused by eating infected meat. The infection that causes the disease in cows is believed to be the same one that causes vCJD in humans.
Varient CJD causes less than 1% of all CJD cases. It tends to affect younger people. Fewer than 200 people worldwide have had this disease. Almost all cases occurred in England and France.
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 very rare inherited human diseases, such as Gerstmann-Straussler-Scheinker disease and fatal familial insomnia
Dementia that gets worse quickly over a few weeks or months
CJD is rarely confused with other types of dementia (such as Alzheimer's disease) because the symptoms get worse much more quickly in CJD.
Exams and Tests
Early in the disease, a nervous system and mental examination will show memory problems and changes in other intellectual functions. Later in the disease, a motor system examination (an exam to test muscle reflexes, strength, coordination, and other physical functions) may show:
Abnormal reflexes or increased normal reflex responses
The disease can only be confirmed with a brain biopsy or autopsy. Today, it is very rare for a brain biopsy to be done to look for this disease.
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.
People with this condition may need help controlling unacceptable or dangerous behaviors. This involves rewarding positive behaviors and ignoring negative behaviors (when it is safe). They may also need help getting oriented to their surroundings.
Getting legal help with advance directives, powers of attorney, and other legal actions early in the disorder can make it easier to make ethical decisions about the CJD patient's care.
The outcome of CJD is very poor. People with sporadic CJD are unable to care for themselves within 6 months or less after symptoms begin.
The disorder is fatal in a short time, usually within 8 months. People who have variant CJD get worse more slowly, but the condition is still fatal. A few people survive for as long as 1 or 2 years. The cause of death is usually infection, heart failure, or respiratory failure.
The course of CJD is:
Infection with the disease
Loss of ability to interact with others
Loss of ability to function or care for oneself
When to Contact a Medical Professional
CJD is not a medical emergency. However, getting diagnosed and treated early may make the symptoms easier to control, give patients time to make advance directives and prepare for the end of life, and give families extra time to come to terms with the condition.
Medical equipment should be treated to remove the proteins that may cause the disease. People who have a history of CJD should not donate a cornea or other body tissue.
Most countries now have strict guidelines for managing infected cows to avoid transmitting CJD to humans.
DeKosky ST, Kaufer DI, Hamilton RL, Wolk DA, Lopez OL. The dementias. In: Bradley WG, Daroff RB, Fenichel GM, Jankovic J, eds. Neurology in Clinical Practice. 5th ed. Philadelphia, PA: Elsevier Butterworth-Heinemann; 2008:chap 70.
Swaminathan A, Kedar S. Creutzfeldt-Jakob disease. In: Alvero R, Borkan JM, Ferri FF, et al., eds. Ferri's Clinical Advisor. 1st ed. Philadelphia, PA: Elsevier Saunders; 2014.
Joseph V. Campellone, MD, Division of Neurology, Cooper University Hospital, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.