ENCEPHALOPATHY
E
CAUSES
Encephalomyelitis develops as a rare
complication of
measles
or, less com-
monly, of other viral infections, such as
chickenpox
,
rubella
(German measles),
or glandular fever (see
mononucleosis,
infectious
) .
It may also occasionally fol-
low vaccination against
rabies
.
SYMPTOMS
Symptoms of encephalomyelitis include
fever, drowsiness, headache, seizures,
partial
paralysis
or loss of sensation,
and, in some cases,
coma
(a state of
unconsciousness and unresponsiveness
to internal or external stimuli).
DIAGNOSIS AND
TREATMENT
Diagnosis is based on the results of blood
tests;
CTscanning
or
MRI
(techniques that
produce cross-sectional or three-dimen-
sional images of the body structures);
EEG
(a method of recording the electrical
activity of the brain);
lumbar puncture
(taking a sample of fluid from the spinal
canal for analysis); and, rarely, a brain
biopsy
(removal of a small sample of
brain tissue for microscopic analysis).
There is no cure for the disease, but
corticosteroid drugs
are given to reduce
inflammation and
anticonvulsant drugs
to control seizures.
OUTLOOK
The disease is often fatal; those who
survive may suffer permanent damage
to the nervous system.
encephalomyelitis, myalgic
Another term for the disorder
chronic
fatigue syndrome
.
encephalopathy
Any disorder affecting the
brain
,
espe-
cially chronic degenerative conditions.
TYPES
Wernicke’s encephalopathy is a degen-
erative condition of the brain caused by
a deficiency of vitamin Bj
(see
Wer-
nicke-Korsakoff syndrome
) .
Hepatic encephalopathy is caused by
the effect on the brain of
toxins
that
have built up in the blood as a result of
liver failure
.
It may lead to impaired con-
sciousness, memory loss, a change in
personality, tremors, and
seizures
.
In
spongiform
encepalopathy,
the
brain tissue shrinks and spaces develop
w ithin it; this leads to severe problems,
such as paralysis and
dementia
.
Bovine
spongiform encephalopathy (BSE) is a
disorder contracted by cattle after they
are given feed containing material from
sheep or cattle. The cause of BSE is
believed to be an infective agent that is
known as a
prion
.
Some cases of variant
Creutzfeldt-Jakob disease
in humans have
been attributed to infection with the
prions responsible for BSE, w hich were
probably transmitted to
humans
via
consumption of meat products.
(See
also
hypertensive encephalopathy
.)
enchondroma
A noncancerous bone tumour that orig-
inates in cartilage in the
metaphysis
(the
area in w hich new tissue is added as
the bone grows).
encoding
The first stage in the
memory
process,
also called registration. In this stage,
information received by one
of the
senses (such as hearing or sight) is reg-
istered and then modified ready for
storage by the brain. The information
can then be retrieved when it is needed.
encopresis
A type of
soiling
in w hich children pass
normal faeces in unacceptable places
after the age at w hich bowel control has
been
achieved. There
is
usually
an
underlying behavioural problem
(see
behavioural problems in children
).
endarterectomy
An
operation
to
remove
the
lining
of an
artery
affected by
atherosclerosis
(narrowing
due to
deposits of fatty
material). Removing the diseased lining
restores normal blood flow to the part
of the body supplied by the artery.
WHY IT
IS DONE
Endarterectomy is used to treat
cere-
brovascular disease
(in w hich the blood
supply to the brain is seriously reduced)
and
peripheral vascular disease
(in which
blood supply to the limbs is impaired).
HOW
IT IS DONE
Endarterectomy is a delicate procedure
that may take several hours. The opera-
tion may be performed endoscopically
(see
endoscopy
) or by open surgery. In
open surgery, the artery is exposed,
clamps are applied, an incision is made,
and the diseased lining, as well as any
thrombus (blood clot) that may have
formed, are removed. The incision is
closed with stitches.
RESULTS
New lining grows in the artery w ithin a
few weeks of surgery. W hen narrowing
of the arteries is widespread (in other
words, it is not confined to a single
artery),
arterial reconstructive surgery
may
have to be performed.
endarteritis
Inflammation of the inner
(intimal)
layer of an
artery
wall. Endarteritis most
commonly occurs as a result of a bac-
terial infection such as
syphilis
.
The
causative infection is treated with
anti-
biotic drugs
,
such as penicillin.
end artery
An
artery
(a blood vessel that carries
blood away from the
heart
) ,
or the final
branch
of an artery,
that
does
not
communicate with any other arteries.
An end artery is therefore the sole sup-
plier
of
blood
to
its
surrounding
tissues. If an end artery is damaged and
can no longer supply blood to an area,
the tissues of that area may die. End
arteries are found in the
brain
,
heart,
retina, kidneys, and spleen.
endemic
A term applied to a disease or disorder
that is constantly present in a particular
region or in a specific group of people.
AIDS
,
for example, has become endemic
in central Africa. An endemic disease
contrasts with an
epidemic,
w hich is
not generally present but occasionally
affects a large group of people.
endemic goitre
A type of
goitre
(a swelling of the neck
due to enlargement of the
thyroid gland
)
that occurs in certain parts of the world
due to a deficiency of
iodine
in the diet.
Iodine is necessary for the production
of the
thyroid hormones
triiodothyronine
(T3) and thyroxine (T4). If there is too
little iodine in the diet, the thyroid
gland compensates for the deficiency by
enlarging in order to produce sufficient
amounts of thyroid hormones.
Endemic goitre is rare in the devel-
oped world. It may be treated using
dietary measures alone.
endocarditis
Inflammation of the endocardium (the
membrane
that
lines
the
inside
of
the heart), particularly the endocardium
lining the
heart valves
.
CAUSES AND
INCIDENCE
Endocarditis is most often caused by
infection w ith
bacteria
,
fungi
,
or other
microorganisms, w hich may be intro-
duced into the body during surgery
(including dental procedures); by
intra-
venous
injection using dirty needles; or
through breaks in the skin or mucous
membranes. The organisms travel in the
bloodstream to the heart. As a result, the
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