FAECES, ABNORMAL
F
faeces, abnormal
Faeces that differ from normal in their
colour, odour, consistency, or content.
Abnormal faeces may be an indication
of a disorder of the
digestive system
or
a related organ, such as the
liver
.
A
change in the character of faeces, how-
ever,
is most often the result
of a
change in diet.
Diarrhoea
(frequent passage of liquid
or very loose faeces) may simply be due
to anxiety. However, it may be the result
of an intestinal infection (see
gastro-
enteritis
) ,
an intestinal disorder (such as
ulcerative colitis
or
Crohn’s disease
) ,
or
irritable bowel syndrome
.
Loose stools may
also be an indication of
malabsorption
(impaired absorption of nutrients by
the small intestine).
Constipation
(infrequent
passage
of
very hard faeces) is generally harmless.
Constipation
that
develops
unexpec-
tedly,
however, may be caused by a
disorder of the large intestine, such as
cancer (see
colon, cancer of
) .
Pale faeces may be caused by diarrh-
oea, a lack of bile in the intestine as a
result of
bile duct obstruction
,
or a dis-
ease that causes malabsorption (such
as
coeliac disease
) .
In malabsorption, the
paleness is caused by the high fat con-
tent of the faeces. This type of faeces
may be oily, foul-smelling, and difficult
to flush away.
Dark faeces may result from taking
iron tablets. If the faeces are black,
however, there may be bleeding in the
upper digestive tract.
Faeces that contain excessive mucus
are sometimes associated with constipa-
tion or with irritable bowel syndrome.
Enteritis
,
dysentery
,
or a tumour of the
intestine (see
intestine, tumours of
)
may
also
lead
to
the
passage
of excess
mucus, often accompanied by blood.
Blood in the faeces differs in appear-
ance depending on the site of bleeding.
Bleeding from the stomach or duo-
denum is usually passed in the form of
black, tarry faeces (see
melaena
) .
Blood
from the colon is red and is usually
passed at the same time as the faeces.
Bleeding from the rectum
or anus,
w hich may be due to tumours or to
haemorrhoids
(piles), is usually bright
red. Occasionally, however, it may not
even be visible (see
occult blood, faecal
) .
(See also
rectal bleeding
. )
faeces, blood in the
See
faeces, abnormal; occult blood, faecal;
rectal bleeding
.
Fahrenheit scale
A temperature scale in w hich the melt-
ing point of ice is 3 2° and the boiling
point of water is 2 1 2°. On this scale,
normal body temperature is 98.6°F,
w hich is equivalent to 3 7° Celsius (C ).
To convert a temperature in Fahrenheit
to its Celsius equivalent, subtract 32
and
multiply
by
0.5
6
(or
s/9). To
convert
a
Celsius
temperature
to
Fahrenheit, m ultiply by
1.8
(or
9
/
5
)
then add 3 2. (See also
Celsius scale
. )
Fahr’s disease
A rare, degenerative neurological dis-
order
that
is
characterized
by
the
appearance of abnormal calcium depos-
its and is associated cell loss in certain
areas of the brain. Fahr’s disease may be
familial
,
in w hich it shows either an
autosomal recessive or autosomal dom-
inant pattern of inheritance (see
genetic
disorders
) .
In many cases, however, the
cause of the disorder is unknown.
Symptoms of fahr’s disease include
progressive
dementia
(deterioration in
brain function) and the loss of acquired
motor skills. Increased muscle stiffness
and
restricted
movements
may
also
develop. Possible complications include
athetosis
,
characterized by slow, invol-
untary, w rithing movements, or
chorea
,
characterized by irregular, rapid, jerky
movements. There may also be gradual
deterioration of eyesight.
Individual symptoms of Fahr’s dis-
ease are treated where possible, but
there is no cure.
failure to thrive
Failure of expected growth in an infant
or toddler, usually assessed by compar-
ing the rate at w hich a baby gains
weight w ith measurements on a stan-
dardized
growth chart
.
An undiagnosed m inor illness such
as a urinary infection
may be
the
cause; in some cases, failure to thrive
suggests a more serious disorder such
as congenital
heart disease
or
kidney fail-
ure
.
Emotional or physical deprivation
can result in failure to thrive, especially
if the child is undernourished or neg-
lected. A child who fails to grow at the
appropriate rate needs to undergo tests
to
determine
the
cause.
(See
also
growth, childhood
;
child development
.)
fainting
Temporary loss of consciousness due
to reduced blood flow to the brain. The
medical term is “syncope” .
CAUSES
Episodes of fainting are often due to a
vasovagal attack
- an episode in w hich
overstimulation
of
the
vagus nerve
(which controls vital organs such as the
lungs and
heart)
causes slowing
of
the heartbeat and a fall in blood pres-
sure,
thereby
reducing
the
flow
of
blood to the brain. Attacks are usually
preceded by sweating, nausea, dizzi-
ness, and weakness, and are commonly
the result of pain, stress, shock, a stuffy
atmosphere,
or
prolonged
coughing.
Fainting may also result from postural
hypotension
(low blood pressure), w hich
may occur when a person stands still
for a long time or stands up suddenly.
This problem is common in elderly
people, in those with
diabetes mellitus
,
and
in
those
taking
antihypertensive
drugs
or
vasodilator drugs
.
TREATMENT
In most cases, recovery from fainting
occurs when normal blood flow to the
brain is restored. This restoration usu-
ally happens w ithin minutes because
the loss of consciousness results in the
person falling into a lying position,
w hich restores the flow of blood to the
brain. Medical attention is required in
cases of prolonged
unconsciousness
or
repeated attacks of fainting.
faith-healing
The supposed ability of certain people
to cure disease by a healing force inex-
plicable to science.
falciparum malaria
The
most
severe
form
of
malaria
,
w hich is caused by the parasitic proto-
zoan P
l a s m o d i u m f a i c i p a r u m
.
fallen arches
One of the causes of
flat-feet
.
Fallen
arches can develop as a result of weak-
ness of the muscles that support the
arches of the foot.
fallopian tube
One of the two tubes that extend from
the
uterus
to each
ovary
.
The fallopian
tube transports eggs and sperm and is
where
fertilization
takes place.
STRUCTURE
The
funnel-shaped
fallopian
tube
is
about 10 cm long. It opens into the
uterus at one end. The other end, w hich
is divided into
fimbriae
(fingerlike pro-
jections), lies close to the ovary. The
tube has muscular walls lined by cells
with cilia (hairlike projections).
296
previous page 295 BMA A Z Family Medical Encyclopedia   2004 read online next page 297 BMA A Z Family Medical Encyclopedia   2004 read online Home Toggle text on/off