soft paraffin, and liquid paraffin that is
used to smooth, soothe, and hydrate
the skin in all dry or scaling conditions.
Rarely, ingredients such as preserva-
tives may result in sensitization.
enalaprilAn ACE inhibitor drugused to
treat hypertensionand heart failure.
enamel, dentalThe hard outer layer of
a tooththat covers and protects the
inner structures.
encephalitisInflammation of the brain,
and sometimes also the meninges, usu-
ally due to a viral infection. Encephalitis
varies in severity from mild, in which
symptoms are barely noticeable, to
serious and potentially life-threatening.
Mild cases can be due to glandular
fever (see infectious mononucleosis) or
may be a complication of childhood
diseases such as mumpsor measles.
The most common cause of life-threat-
ening encephalitis is herpes simplex,
particularly in people with HIV.
Mild cases usually develop over sever-
al days and may cause only a slight
fever and mild headache. In serious
cases, symptoms develop rapidly and
include weakness or paralysis, speech,
memory, and hearing problems, and
gradual loss of consciousness; coma
and seizuresmay also occur. If the
meninges are inflamed, other symp-
toms may develop, such as a stiff neck
and abnormal sensitivity to light.
Diagnosis is based on results of blood
tests, CT scanningor MRI, EEG, lumbar
puncture, and, rarely, a brain biopsy.
Encephalitis due to herpes simplex is
treated with intravenous infusion of the
antiviral drug aciclovir, but there is
no known treatment for encephalitis
caused by other viral infections.
encephalitis lethargicaAn epidemic
form of encephalitis. There have been no
major outbreaks since the 1920s, but
rare sporadic cases still occur. Many
people who survived the initial illness
during the major epidemics developed
post-encephalitic Parkinson’s disease.
encephaloceleA type of neural tube
defectthat results in defects of the
brain rather than of the spinal cord, as
occurs in spina bifida.
encephalomyelitisInflammation of the
brain and spinal cord, causing damage
to the nervous system. Encephalomyeli-
tis develops as a rare complication of
measlesor, less commonly, of other viral
infections such as chickenpox, rubella,
or infectious mononucleosis. Symptoms
include fever, headache, drowsiness,
seizures, partial paralysisor loss of sen-
sation, and, in some cases, coma.
Diagnosis is as for encephalitis. There is
no cure, but corticosteroid drugsare
given to reduce inflammation and anti-
convulsant drugsto control seizures.
The disease is often fatal; those who
survive may have permanent damage to
the nervous system.
Myalgic encephalomyelitisis another
term for chronic fatigue syndrome.
encephalopathyAny disorder affecting
the brain, especially chronic degenera-
tive conditions.
Wernicke’s encephalopathy is a degen-
erative condition of the brain caused by
a deficiency of vitamin B1 (see Wer-
nicke–Korsakoff syndrome).
Hepatic encephalopathy is caused by
the effect on the brain of toxic sub-
stances (see toxin) that have built up in
the blood as a result of liver failure. It
may lead to impaired consciousness,
memory loss, a change in personality
tremors, and seizures.
Bovine spongiform encephalopathy, or
BSE, is a disorder contracted by cattle
after they are given feed containing
material from sheep or cattle. The cause
seems to be an infective agent known
as a prion. Some cases of new variant
Creutzfeldt–Jakob disease in humans
have been attributed to infection with
the prions responsible for BSE, proba-
bly transmitted in meat products.
encopresisA type of soilingin which
children pass normal faeces in unac-
ceptable places after the age at which
bowel control is normally achieved. The
cause of encopresis is usually an under-
lying behavioural problem.
endarterectomyAn operation to re-
move the lining of an arteryaffected by
atherosclerosis,restoring normal blood
flow. Endarterectomy is used to treat
cerebrovascular diseaseand peripheral
vascular disease. The procedure can be
performed endoscopically (see endos-
copy) or by open surgery.ENALAPRIL ENDARTERECTOMY
E