CHALAZION
CHEST PAIN
insects commonly called cone-nosed or
assassin bugs. The
parasites
live in the
bloodstream and can affect the heart,
intestines, and nervous system. Symp-
toms include swelling of the lymph nodes
and fever. Long-term complications in-
clude damage to the heart. The drug
nifurtimox kills the parasites in the
blood but has unpleasant side effects.
chalazion
A round, painless swelling in
the upper or lower eyelid caused by
obstruction of one of the meibomian
glands that lubricate the edge of the
eyelids. Chalazions are sometimes called
meibomian cysts. They are particularly
common in people suffering from
acne
,
rosacea,
or seborrhoeic
dermatitis
. If the
cyst becomes infected the eyelid becomes
more swollen, red, and painful. A large
swelling putting pressure on the
cornea
at the front of the eye can cause blurring
of vision. About a 3rd of chalazions dis-
appear without treatment, but large
cysts may need to be removed surgically.
chancre, hard
An
ulcer,
usually on the
genitals, that develops during the first
stage of
syphilis.
chancroid
A sexually transmitted disease,
found mainly in the tropics, character-
ized by painful
ulcers
on the genitals
and enlarged lymph nodes in the groin.
The disorder is caused by the bacterium
Haemophilus ducreyi.
Prompt treatment
with
antibiotic drugs
is usually effective.
chapped skin
Sore, cracked, rough skin,
usually on the hands, face, and particu-
larly the lips, due to dryness. Chapping
is caused by the lack, or removal, of the
natural oils that keep skin supple. It tends
to occur in cold weather, when oil-secret-
ing glands produce less oil, or after
repeated washing or wetting. Treatment
is with a lanolin-based cream.
charcoal
A form of carbon used in
medicine mainly as an adsorbent agent
in the emergency treatment of some
types of poisoning and drug overdose.
Charcot-Marie-Tooth disease
An in-
herited muscle-wasting disease of the
legs (see
peroneal muscular atrophy
).
Charcot's joint
A joint that is repeated-
ly damaged by injuries that have gone
unnoticed because of loss of sensation
in the joint (see
neuropathic joint
).
check-up
See
examination, physical.
cheilitis
Inflammation, cracking, and dry-
ness of the lips that may be caused by
ill-fitting dentures, a local infection, aller-
gy to cosmetics, excessive sunbathing,
or deficiency of riboflavin (vitamin B3).
chelating agents
Chemicals used in
the treatment of metal poisoning that
act by combining with metals such as
lead, arsenic, and mercury to form less
poisonous substances.
Penicillamine
is
a commonly used chelating agent.
chemist
Another term for a pharmacist.
chemotherapy
The term that usually
describes the use of drugs to treat
can-
cer
but which may also describe the use
of
antibiotics
to treat infectious diseases.
Chemotherapy works by destroying bac-
teria or cancer cells or by preventing
them from multiplying. Cancer chemo-
therapy drugs may also have effects on
normal tissue such as bone marrow,
the intestinal lining, the hair follicles, the
ovaries and testes, and the mouth,
sometimes causing severe side effects.
chenodeoxycholic acid
A chemical in
bile
that reduces the amount of
choles-
terol
released by the
liver
into the bile.
It is sometimes used to treat small gall-
stones, if they contain mainly cholesterol
and no calcium. Side effects include
diarrhoea and, rarely, liver damage.
chest
The upper part of the trunk.
Known technically as the
thorax
, the
chest extends from the base of the neck
down to the
diaphragm.
chest compression
Also called cardiac
compression massage (see
cardiopul-
monary resuscitation
).
chest pain
Pain in the chest, which is
often without serious cause, but which
may be a symptom of an underlying dis-
order requiring urgent treatment. The
pain may be in the chest wall or in an
organ within the chest. The most com-
mon causes of pain in the chest wall are
a strained muscle or an injury, such as
a broken rib. A sharp pain that travels
to the front of the chest may be due to
pressure on a nerve root attached to the
spinal cord as a result of, for example,
osteoarthritis
of the
vertebrae
. Pain in
the side of the chest may be due to
pleurodynia.
The viral infection
herpes
zoster
(shingles) may cause severe pain
along the course of a nerve in the chest
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