Creutzfeldt-Jakob disease (CJD) A rare degen-
erative, and at present fatal, BRAINcondition that
results from the distortion and malfunction of pro-
teins in the brain. Protein particles called prions
appear to be the responsible agents. Prions are
infectious, meaning they can pass from one per-
son to another to cause disease. CJD is a brain-
wasting disease that destroys brain tissue, leaving
spongelike holes throughout the brain. Doctors
diagnose about 300 cases of CJD a year in the
United States, though many researchers feel this is
an inaccurate representation of how many people
develop the condition because diagnosis can take
place only by examining brain tissue at autopsy.
Autopsy is not a standard procedure in the United
States or in most countries.
Though known to doctors for more than a cen-
tury, CJD came to international prominence in the
early 1990s with the discovery that a form of
prion infection in cows, bovine spongiform
encephalopathy (BSE), could be transmitted to
humans through consumption of meat in which
the nervous tissues present in the meat contained
infectious prions (infectious prions occur only in
nervous tissue). Researchers designated this form
as variant CJD (vCJD) to distinguish it from the
classic form of CJD.
Another form of CJD is iatrogenic CJD in
which an individual acquires the disease as a
result of medical treatments using tissues from a
cadaver donor with had undiagnosed CJD. Cur-
rent methods for harvesting such tissues and sub-
stances, notably dura mater for transplantation
and human growth HORMONE (hGH) extracted
from cadaver PITUITARY GLAND, now include proce-
dures to reduce the risk for INFECTION.
CJD is a difficult disease to track to its origins
because the time from onset to show of symptoms
can be several decades. Before BSE (also called
“mad cow disease”) focused attention on CJD,
doctors believed the malformed proteins charac-
teristic of CJD occurred spontaneously in individ-
uals who perhaps had a GENETIC PREDISPOSITIONfor
such damage or had unknown environmental
exposure that set the chain of events in motion.
Some forms of CJD appear to have a genetic com-
ponent as they tend to run in families, and
researchers have identified GENEmutations that
produce the defective proteins.
The discovery of infectious prions has caused
some researchers to suspect that these protein par-
ticles cause nearly all CJD. Researchers do not
know, however, how most people would acquire
infectious prions. Only about 110 people world-
wide (mostly in England where BSE first surfaced)
are known to have died from CJD acquired
through eating BSE-contaminated beef. About
150 people worldwide are known to have died
from iatrogenic CJD acquired through medical
procedures. Health-care providers and suppliers of
donor tissues and products now follow more strin-
gent preparation and sterilization techniques to
kill infectious prions. These measures significantly
reduce, though do not eliminate, the risk of
acquired CJD.Symptoms and Diagnostic Path
Though the incubation period for CJD is typically
very long (10 to 25 years), once symptoms
develop the course of the disease is quite rapid.
Symptoms tend to appear with dramatic sudden-
ness and include- erratic behavior and emotional outbursts
- memory disturbances
- DEMENTIA
- loss of motor function (jerky movements and
unsteady gait) - cognitive dysfunction
- loss of motor function (jerky movements and
The diagnostic path includes a comprehensive
PERSONAL HEALTH HISTORYto determine any family
history or exposures that suggest CJD as well as
imaging procedures such as COMPUTED TOMOGRAPHY
(CT) SCANand MAGNETIC RESONANCE IMAGING(MRI),
which can show the damage in the brain. The
neurologist makes the diagnosis on the basis of
clinical findings, including the progression of
symptoms, after ruling out other causes. Definitive
diagnosis can be made only by analysis of brain
tissue after death.Treatment Options and Outlook
All forms of CJD are, at present, progressive and
fatal. Treatment is primarily palliative, aiming to
improve the person’s comfort and QUALITY OF LIFE
to the extent possible. CJD typically results in loss248 The Nervous System