How Creutzfeldt-Jakob Disease Differs from Alzheimer's

This Disease Is Sometimes Mistakenly Called "Mad Cow Disease"

What Is Creutzfeldt-Jakob Disease (CJD)?

Creutzfeldt-Jakob (pronounced CROYZ-felt YAH-cob) disease is a very rare neurodegenerative brain disorder that affects about one person in a million. It is one of several types of prion diseases.

CJD may also be referred to as transmissible spongiform encephalopathy, vCJD, and Jacob-Creutzfeldt disease.


The United States has about 200 to 300 cases a year.

The average age of onset is 60 years old.

Symptoms of CJD

Very early symptoms include depression-like withdrawal, mood changes and a lack of interest in people or circumstances. Quickly, other symptoms develop, including memory problems, changes in behavior, poor coordination, unsteady walking and impaired vision.

As the disease continues to progress, people with CJD may experience hallucinations, psychosis, deterioration of coordination, involuntary movements, very weak arms and legs, poor ability to swallow and speak, and further mental impairments. Eventually, the person may slip into a coma.

Categories of CJD

  • Sporadic
    Sporadic CJD accounts for approximately 85% of all cases of the disease. Sporadic means that there is no clear cause.
  • Hereditary
    According to the National Institute of Neurological Disorders and Stroke, inherited cases account for approximately 5% to 10% percent. The prion protein gene becomes abnormal in people with all types of CJD. In patients who have the familial form, mutations have been found in the prion protein gene that cause protein abnormalities. These people usually show a family history of prion disease.
    • Acquired
      There are three types of acquired CJD. These include:
    1. Iatrogenic
      This refers to CJD that is contracted through medical procedures, such as unsterilized instruments or infected tissue transplants.
    2. Kuru
      CJD can be acquired through cannibalism, which is referred to as Kuru. This dates back to the 1950s, when people of the Fore tribe in Papua, New Guinea developed many cases of CJD because their funeral practices included women and children eating the brains of the deceased. As that practice has ceased, cases of CJD have decreased, but this has taken several years because the incubation period for CJD appears to be as long as 40 years.
    1. Variant
      Variant CJD is thought to be caused by eating infected meat and may occur in younger people, with an average age of onset occurring at 28. This is often incorrectly called mad cow disease or bovine spongiform encephalopathy. Mad cow disease occurs only in cows; when it is transmitted to humans, it’s called variant CJD. This kind of CJD is very rare; only three cases have been documented in the United States, with two of those in people who had been previously out of the country.

    Diagnosing CJD

    Like several other neurological disorders, there is no simple test to diagnose CJD. The physician’s first goal is to rule out other conditions that might be causing the dementia, especially because some causes of dementia are reversible, such as normal pressure hydrocephalus and vitamin B12 deficiency.

    Tests such as a spinal tap, EEG, CT, and MRI may be used to determine the likelihood of CJD.

    To confirm a diagnosis, surgeons can do a biopsy by removing a tiny piece of the brain to test. The other option is to conduct an autopsy after death.

    With a biopsy and autopsy, there is a risk for the surgeon to become infected with CJD when he or she handles the brain tissue. In variant CJD, there have been cases confirmed following the removal and testing of a person’s tonsils. It’s therefore very important that proper precautions be taken during a procedure.

    How Is CJD Different than Alzheimer’s?

    The progression of CJD is much faster than in Alzheimer’s disease. People with CJD often die within a few weeks to one year. In Alzheimer’s, there is typically a slow decline over the course of several years.

    Treatment of CJD

    Currently, there is no treatment for CJD, although some of the symptoms can be relieved by medications. The goal is to provide comfort and relief. Research continues to be conducted on identifying causes as well as possible medications to treat CJD.


    A.D.A.M. Creutzfeldt-Jakob Disease.Accessed February 10, 2012.

    Alzheimer’s Association. Creutzfeldt-Jakob Disease. Accessed February 10, 2012.

    Creutzfeldt-Jakob Disease Foundation, Inc. CJD Fact Sheet. Accessed February 10, 2012.

    Creutzfeldt-Jakob Disease Foundation, Inc. Creutzfeldt-Jakob Disease and other Prion Diseases. Accessed February 10, 2012.

    World Health Organization. Creutzfeldt-Jakob disease. Accessed February 10, 2012.

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