Thirty years ago, few people had heard of Creutzfeldt-Jakob disease (CJD).
Today, it has made the news mostly from its possible link to mad cow disease. To help
make
sense of this puzzling disease, take this quiz, based on information from the CDC
and the
National Institute of Neurological Disorders and Stroke (NINDS).
1. CJD is a rare, degenerative, fatal brain disorder.
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It was
named after 2 German psychiatrists, Hans Gerhard Creutzfeldt and Alfons Maria Jakob.
CJD
is classified as a transmissible spongiform encephalitis (TSE). Spongiform refers
to the
description of the affected brain, which becomes filled with so many holes that it
resembles a sponge. There are 4 forms of CJD: sporadic, which arises spontaneously;
familial, or inherited; acquired (very rare), which is passed on by pituitary growth
hormone obtained from cadavers or through contaminated surgical tools; and a new variant
of CJD (v-CJD), linked to "mad cow disease." Besides CJD, there are 4 other TSEs that
affect people: kuru, which was found in an isolated tribe in Papua, New Guinea;
Gerstmann-Sträussler-Scheinker syndrome (an inherited condition); fatal familial
insomnia (an inherited condition); and sporadic fatal insomnia. These diseases are
very
rare. CJD itself occurs only in 1 case per 1 million people. In the U.S., about 200
cases are reported each year.
2. CJD usually appears in childhood.
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Symptoms
of classic CJD typically appear about age 60. Symptoms of new variant CJD (v-CJD)
or of
CJD caused by contaminated pituitary growth hormone can first appear in the early
20s to
early 40s. About 9 in 10 people die within a year of symptoms.
3. A failing memory and lack of coordination are early symptoms of classic CJD.
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But these
symptoms are the same as for other forms of dementia or illness, which makes it
difficult to diagnose. Other symptoms of CJD include behavioral changes and visual
disturbances. As the disease gets worse, symptoms include mental deterioration,
involuntary movements, blindness, weakness of limbs, and coma.
4. Radiation exposure causes CJD.
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The exact
cause is still under investigation, but most researchers believe that CJD is caused
by
an abnormal prion, which is a particular kind of protein. Normal prions are harmless
and
found in every cell in the body. Abnormal prions take a slightly different shape and
clump together in fibers and plaques. Researchers aren't sure what role these fibers
and
plaques play in CJD. In up to 3 in 20CJD cases, the abnormal prion has been inherited.
5. CJD can be passed on through sexual contact.
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CJD is
not a sexually transmitted infection, nor is it a contagious one. It can't be passed
from person to person. People in the same home as a person with CJD will not get the
disease. The FDA now bans blood donations from people who have spent an extended time
in
England or Europe because of concerns that CJD may be passed through blood products.
But
there is no documented case in which prions have been passed through blood products.
The
only proven manner in which CJDhas been passed on from an infected person is through
contaminated tissue (a cornea, for instance) or contaminated surgical tools. Normal
sterilization procedures such as cooking or boiling do not destroy prions.
6. A biopsy is the only way to confirm a diagnosis of CJD.
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In a
brain biopsy, a neurosurgeon removes a small piece of the brain to be examined. But
a
biopsy has several drawbacks. The procedure may be dangerous for the patient, and
the
brain sample removed may not be a part that's affected by CJD. Researchers have
developed a safer test, which looks for a particular protein in a patient's
cerebrospinal fluid. But this test is not yet commercially available. An autopsy after
death can also confirm the illness.
7. CJD can be treated with antiviral medicine.
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Currently, there is no treatment for CJD. Medicine is given to relieve symptoms, but
does not change the course of the disease. It is always fatal.
8. CJD is the same disease as bovine spongiform encephalopathy
(BSE), also known as mad cow disease.
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BSE and
CJD are similar but not the same. BSE is a progressive nervous system disorder in
cattle. It's similar to a disease in sheep called scrapie. BSE has been found mainly
in
cattle in the United Kingdom, but also in other areas of Europe. It has not been found
in U.S. cattle, according to the USDA. The USDA has banned beef imports from England
and
Europe to prevent bringing in contaminated meat. Researchers believe that BSE may
be
caused by feeding scrapie-infected sheep meat-and-bone meal to cattle. They also believe
that a new form of CJD in people called v-CJD, which first showed up in England in
the
early 1990s, is caused by eating beef contaminated by BSE. (Cooking the meat does
not
destroy the prions believed to cause the disease.) The new variant CJD differs from
CJD
in that people who have it are typically much younger (30 versus 60) and that symptoms
are more psychiatric and sensory than neurological.
9. Childhood vaccines given for other illnesses may pose a risk for contracting the
new variant CJD.
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The FDA
and several advisory committees have determined that the risk of contracting v-CJD
through any vaccine (for polio or hepatitis, for example) is remote. The concern about
vaccines surfaced because some vaccines are made using substances derived from cattle.
Some of the bovine components have come from countries where BSE is found. But there
is
no evidence in Europe that any vaccines have caused v-CJD.
