EXOTOXIN
SYMPTOMS
In most cases, exostosis produces no
symptoms. Often it is recognized only
after an injury, when it appears as a
hard swelling. Occasionally, the tumour
presses on a nerve, causing pain or
weakness in the affected area.
DIAGNOSIS AND
TREATMENT
Diagnosis can be confirmed by
X-rays
.
The tumour may be surgically removed
if it is causing symptoms or for cos-
metic reasons.
exotoxin
A poison, released by certain types of
bacteria
(including
tetanus
bacilli and
diphtheria
bacilli), that enters the blood-
stream and causes widespread effects
around the body Exotoxins are among
the most poisonous substances known.
Infections by tetanus, diphtheria, and
some other bacteria that release life-
threatening exotoxins can be prevented
by
immunization
with vaccines consisting
of detoxified exotoxins. Treatment of
such infections usually includes adminis-
tration of
antibiotic drugs
and an
antitoxin
to neutralize the exotoxin.
(See also
endotoxin
;
enterotoxin
. )
exotropia
An
alternative term
for
a divergent
squint
,
in w hich one eye is used for
detailed vision and the other is directed
outwards. (See also
esotropia
. )
expectorants
Cough remedies
that encourage expect-
oration (the coughing up of
sputum
) .
expectoration
The coughing up and spitting out of
sputum
(phlegm). (See also
cough
. )
expiratory reserve volume
The extra volume of air expired in the
fullest possible exhalation; this amount
is in addition to the volume that is nor-
mally expelled when a person is at rest.
The expiratory reserve volume may be
measured in pulmonary function tests.
expiratory stridor
An abnormal noise that is heard when a
person exhales. Expiratory stridor may
occur if the
vocal cords
are partially
obstructing the flow of air or if there is
an obstruction in the
trachea
(the w ind-
pipe) or bronchi (see
bronchus
) ,
w hich
are
the main airways to the
lungs.
Expiratory stridor
may
occur
either
alone or w ith
inspiratorystridor
.
expire
To exhale (breathe out air from the
lungs).The term also means “to die” .
expired gas
Any gas that has been expelled from the
lungs. Expired gas usually contains a
high proportion of
carbon dioxide.
It
may also contain other substances, such
as
alcohol
and
carbon monoxide,
that are
carried in the circulation.
exploratory surgery
Any operation carried out to investigate
or examine part of the body to discover
the extent of known disease or to estab-
lish a diagnosis. Advances in imaging,
such as
MRI
(a technique that produces
cross-sectional
or
three-dimensional
images of body structures), have redu-
ced the need for exploratory surgery.
exposure
A term used to describe the effects on
the body of being subjected to very
low temperatures, or to a combination
of low temperatures, wetness, and high
winds. The prim ary danger in these
conditions is
hypothermia
(a sharp fall
in body temperature).
The term is also used to describe sub-
jection to
radiation,
to environmental
pollutants, or to infectious diseases.
expressing milk
A technique sometimes used by women
who are
breast-feeding,
for removing
m ilk from the breasts. The technique
may be needed if the woman’s breasts
are overfull (see
engorgement
). A woman
may also want to express milk so that it
can be given to the baby in her absence
or so that an infant who is unable to
feed at the breast (due to prematurity,
for example) can still benefit from breast
milk. M ilk can either be expressed by
hand or using a
breast pump.
The milk
may also be frozen for later use.
expressive dysphasia
A type of
dysphasia
(disturbance in the
ability to use and/or understand words)
in w hich the person can understand
others
and
knows
what
he
or she
wishes to say, but has difficulty putting
thoughts into words. (See also
aphasia;
speech; speech disorders; speech therapy.)
exsanguinate
To remove, withdraw, or deprive the
body of circulating
blood.
Exsanguina-
tion usually results from severe internal
or external bleeding. It can also be
performed during surgery to create a
blood-free area for the procedure. (See
also
Esmarch’s bandage
. )
exstrophy of the bladder
A rare
birth defect
in w hich the
bladder
is inside-out and is open to the outside
of the body through a space in the
lower abdominal wall. There are also,
usually, other defects, such as
epispadias
in males (in w hich the opening of the
urethra is on the upper surface of the
penis) and failure of the pubic bones to
join at the front. Untreated, an affected
child constantly leaks urine.
Surgical
treatment
involves
recon-
structing the bladder and closing the
abdominal wall. If the bladder is very
small,
it is removed and the urine
diverted (see
urinary diversion
) .
extensor
Any
muscle
that moves a
joint
in order to
straighten a limb. An example of an
extensor muscle is the
triceps muscle
in
the arm, w hich straightens the elbow.
external cardiac massage
Rhythmic pressure applied to the chest
in order to maintain circulation if a per-
son’s heart has stopped beating. The
lower breastbone is squeezed repeatedly
with the heels of the hands, in order to
compress the heart
(see
cardiac mas-
sage
) .
External cardiac massage may be
used in first aid, as part of
cardiopul-
monaryresuscitation
.
external fixation
The insertion of pins through the skin
to hold together parts of a broken bone
(see
fracture
) .
The pins are held in place
by an external metal frame. Usually, the
affected limb can be used w ithin a few
days; the frame and pins are removed
under anaesthesia when the bone has
healed. (See also
internal fixation
. )
external haemorrhoids
Haemorrhoids
(dilated veins) that form
around the outside of the
anus
.
Haem-
orrhoids are commonly known as piles.
The condition is sometimes associated
with
internal haemorrhoids
,
those
that
develop higher up inside the anal canal.
If the blood in an external haemorrhoid
clots, the resulting swelling is termed a
perianal
haematoma
.
This condition is
very
painful
but
usually
disappears
within about five days. (See also
haem-
orrhoidectomy
;
internal haemorrhoids
. )
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