relieve aches and pains. Other common
ingredients include antihistamine drugs
and decongestant drugsto reduce nasal
congestion; caffeine, which acts as a
mild stimulant; and vitamin C.
cold soreA small skin blister, usually
around the mouth, commonly caused
by a strain of the herpes simplexvirus
called HSV1 (herpes simplex virus type
1). The first attack of the virus may be
symptomless or may cause a flu-like ill-
ness with painful mouth and lip ulcers
called gingivostomatis. The virus then lies
dormant in nerve cells, but may occa-
sionally be reactivated and cause cold
sores. Reactivation may occur after ex-
posure to hot sunshine or a cold wind,
during a common cold or other infection,
or in women around the time of their
menstrual periods. Prolonged attacks can
occur in people with reduced immunity
to infection due to illness or treatment
with immunosuppressant drugs.
In many cases, an outbreak of cold
sores is preceded by tingling in the lips,
followed by the formation of small blis-
ters that enlarge, causing itching and
soreness. Within a few days they burst
and become encrusted. Most disappear
within a week.The antiviral drug aci-
clovirin a cream may prevent cold sores
if used at the first sign of tingling.
colecalciferolAn alternative name for
vitamin D 3 (see vitamin D).
colectomyThe surgical removal of part
or all of the colon. Colectomy is used in
severe cases of diverticular diseaseor to
remove a cancerous tumour in the colon
or a narrowed part of the intestine that
is obstructing the passage of faeces. A
total colectomy is carried out when
ulcerative colitiscannot be controlled by
drugs, and may be used in cases of
familial polyposis.
In a partial colectomy, the diseased
section of the colon is removed, and the
ends of the severed colon are joined. A
temporary colostomymay be required
until the rejoined colon has healed. In a
total colectomy, the whole of the large
intestine is removed, with or without
the rectum. If the rectum is removed, an
ileostomymay be performed. The bowel
usually functions normally after a par-
tial colectomy. In a total colectomy, thereduced ability of the intestines to ab-
sorb water from the faeces can result
in diarrhoea. Antidiarrhoeal drugsmay
therefore be required.
colestyramineA lipid-lowering drug
used to treat some types of hyperlipi-
daemia. The drug is also used to treat
diarrhoea due to excessive amounts of
undigested fats in the faeces in disor-
ders such as Crohn’s disease.
colicA severe, spasmodic pain that
occurs in waves of increasing intensity.
(See also colic, infantile.)
colic, infantileEpisodes of irritability,
and excessive crying in otherwise
healthy infants, thought to be due to
spasm in the intestines. A baby with an
attack of colic cries or screams inces-
santly, draws up the legs towards the
stomach, and may become red in the face
and pass wind. Colic tends to be worse
in the evenings. The condition is dis-
tressing but harmless. Usually, it first
appears at 3–4 weeks and clears up with-
out treatment by the age of 12 weeks.
colistinOne of the polymyxingroup of
antibiotic drugsused in topicalprepara-
tions for eye and ear conditions. It is
only used to treat systemic infections
that are resistant to other antibiotics.
The drug may cause damage to the kid-
neys and nerve tissue.
colitisInflammation of the coloncaus-
ing diarrhoea, usually with blood and
mucus. Other symptoms may include
abdominal pain and fever. Colitis may
be due to infection by various types of
microorganism, such as camphlobacter
and shigellabacteria, viruses, or amoe-
bae. A form of colitis may be provoked
by antibiotic drugsdestroying bacteria
that normally live in the intestine and
allowing CLOSTRIDIUM DIFFICILE, a bacte-
ria that causes irritation, to proliferate.
Colitis is a feature of ulcerative colitis
and Crohn’s disease.
Investigations into colitis may include
examining a faecal sample, sigmoidoscopy
or colonoscopy, biopsyof inflamed areas
or ulcers, and a barium enema (see bari-
um X-ray examinations). If the cause is
an infection, antibiotics may be needed.
Crohn’s disease and ulcerative colitis are
treated with corticosteroid and immuno-
suppressant drugs, and a special diet.COLD SORE COLITISC