Entropion in babies does not disturb
the eye and usually disappears within a
few months. In later life, entropion can
cause irritation, conjunctivitis, damage
to the cornea, or problems with vision.
Surgery to correct entropion can pre-
vent such conditions.
ENT surgerySee otorhinolaryngology.
enuresisThe medical term for bed-wet-
ting. In most cases, it occurs in children
and affects boys slightly more common-
ly than girls. Usually, enuresis occurs as
a result of slow maturation of nervous
system functions concerned with blad-
der control. It may also result from
psychological stress. In a small number
of bed-wetters, there is a physical
cause, such as a urinary tract infection.
If a child wets the bed persistently,
tests, including urinalysis, may be per-
formed to rule out a physical cause. For
bed-wetting that is not caused by a dis-
order, treatment starts with training the
child to pass urine regularly during the
day. Getting the child to go to the toilet
just before bed may be helpful. Alarm
systems are available that involve the
placement of humidity-sensitive pads
in the child’s bed. The child is woken by
the alarm if urine is passed and eventu-
ally learns to wake before urinating.
environmental medicineThe study of
the effects on health of natural environ-
mental factors, for example climate,
altitude, sunlight, and the presence of
various minerals. The study of working
environments is a separate discipline
(see occupational medicine.)
enzymeA proteinthat regulates the
rate of a chemical reaction in the body.
There are thousands of enzymes, each
with a different chemical structure. It is
this structure that determines the spe-
cific reaction regulated by an enzyme.
Different enzymes occur in different
tissues, reflecting their specialized func-
tions. In order to function properly,
many enzymes need an additional com-
ponent, known as a coenzyme, which is
often derived from a vitaminor mineral.
Enzyme activity is influenced by many
factors, and can be increased or inhibit-
ed by certain drugs.
Measuring enzyme levels in the blood
can be useful in diagnosing certain dis-orders. For example, the level of heart
muscle enzymes is raised following a
myocardial infarctionbecause the dam-
aged heart muscle releases enzymes
into the bloodstream. Many different
inherited metabolic disorders, includ-
ing phenylketonuria, galactosaemia, and
G6PD deficiency, are caused by defects
in, or deficiencies of, specific enzymes.
Enzymes can play a valuable role in
treating certain disorders. Pancreatic
enzymes may be given as digestive aids
to people who have malabsorptionrelat-
ed to pancreatic disease. Enzymes such
as streptokinase and tissue-plasminogen
activatorare used to treat acute throm-
bosisand embolism.
eosinophilA type of leukocyte (white
blood cell) that plays a role in the body’s
allergic responses and in fighting para-
sitic infections.
ependymomaA rare brain tumourof
the gliomatype that occurs most often
in children.
ephedrineA drug that stimulates the
release of the neurotransmitter nor-
adrenaline. It is used as a decongestant
drugto treat nasal congestion.
epicanthic foldA vertical fold of skin
extending from the upper eyelid to the
side of the nose. Epicanthic folds are
common in Oriental people but rare in
other races, except in babies, in whom
they usually disappear as the nose de-
velops. Abnormal epicanthic folds are a
feature of Down’s syndrome.
epicondyleA bony outgrowth to which
tendonsare attached (for example, at
the lower end of the humerusbone of
the upper arm where it forms part of the
elbowjoint). Overuse of muscles, lead-
ing to repeated tugging on the tendons,
can cause pain and inflammation at an
epicondyle (see epicondylitis).
epicondylitisPainful inflammation of
an epicondyle, specifically one of the
bony prominences of the elbowat the
lower end of the humerus. It is due to
overuse of forearm muscles, which
causes repeated tugging on the tendons
attaching to the bone. Epicondylitis
affecting the prominence on the outer
elbow is called tennis elbow. When the
prominence on the inner elbow is
affected it is called golfer’s elbow.ENT SURGERY EPICONDYLITISE