CANCER
CAPGRAS' SYNDROME
C
are harboured by animals and can be
passed to humans in contaminated food,
especially poultry, causing
food poison-
ing.
The bacteria also cause a form of
the inflammatory colon disease
colitis.
cancer
A group of diseases character-
ized by the abnormal and unrestrained
growth of cells in body organs or tissues.
Tumour-forming cells develop when the
oncogenes
(genes controlling cell growth
and multiplication) in a cell or cells
undergo a series of changes. A small
group of abnormal cells develop that
divide more rapidly than normal, lack
differentiation
(they no longer perform
their specialized task), and may escape
the normal control of hormones and
nerves. Cancers differ from benign
n eo-
plasms
(abnormal growths, such as
warts)
in that they spread and infiltrate sur-
rounding tissue and may cause blockages,
destroy nerves, and erode bone. Cancer
cells may also spread via the blood ves-
sels and lymphatic system to form
secondary tumours (see
metastasis).
Causes of cancer include environmen-
tal factors such as sunlight, smoking,
pollutants, alcohol consumption, and
dietary factors. These factors may pro-
voke critical changes in body cells in
susceptible people. Susceptibility to cer-
tain cancers may be inherited.
Many cancers are now curable, usually
by combinations of surgery,
radiothera-
py,
and
anticancer drugs.
For information
on particular cancers, refer to the organ
in question (for example
lung cancer;
stomach cancer
).
cancerphobia
An intense fear of devel-
oping cancer, out of proportion to the
actual risk, that significantly affects the
sufferer's life. Patterns of behaviour typ-
ical of
obsessive-compulsive disorder
(for
example,
prolonged washing
rituals)
may be adopted in an attempt to reduce
the risk of cancer.
Psychotherapy
includ-
ing
behaviour therapy
may be of benefit.
cancer screening
Tests to detect early
signs of cancer in groups of people who
are susceptible to cancer because of
their age, occupation, lifestyle, or genetic
predisposition. Tests for cancers of the
cervix (see
cervical sm ear test)
, breast
(see
mammography
), bladder, and colon
have proven to be effective.
cancrum oris
See
noma.
candidiasis
Infection
by
the
fungus
Candida albicans,
also known as thrush
or moniliasis. Candidiasis affects areas
of mucous membrane in the body, most
commonly the vagina and the inside of
the mouth. In infants, it can occur in
conjunction with
nappy rash.
The fungus is normally present in the
mouth and vagina but may multiply
excessively if
antibiotic drugs
destroy the
harmless bacteria that control its growth,
or if the body's resistance to infection is
lowered. Certain disorders, notably
dia-
betes mellitus,
and hormonal changes due
to pregnancy or
oral contraceptives
, may
also encourage its growth. Candidiasis
can be contracted by sexual intercourse
with an infected partner. The infection is
far more common in women than in men.
Symptoms of vaginal infection include a
thick, white discharge, genital irritation,
and discomfort when passing urine. Less
commonly, the penis is infected in men,
usually causing
balanitis.
Oral candidia-
sis produces sore, creamy-yellow, raised
patches in the mouth. Candidiasis may
spread to other moist areas of the body
and may also affect the gastrointestinal
tract, particularly in people with im-
paired immune systems. Treatment for
candidiasis is with topical preparations
such as creams, pessaries, or lozenges,
or with oral
antifungal drugs.
canine tooth
See
teeth.
cannabis
Preparations that are derived
from the hemp plant
cannabis sativa,
which produce euphoria and hallucina-
tions (see
marijuana).
cannula
A smooth, blunt-ended tube
inserted into a blood vessel, lymphatic
vessel, or body cavity, in order to intro-
duce or withdraw fluids. Cannulas are
used for
blood transfusions
and
intra-
venous infusions
and for draining
pleural
effusions.
They may be left in place for
several days if continuous testing of, or
introduction of, fluids is required.
cap, cervical
A flexible contraceptive
device placed directly over the
cervix
to
prevent sperm from entering (see
con-
traception, barrier methods
of).
Capgras' syndrome
The delusion that
a relative or friend has been replaced by
an identical impostor. Also known as the
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