analgesic drugs, and exercising the facial
muscles may aid recovery. In some cases,
it may be necessary to tape the eyelid
shut at bedtime in order to avoid the
risk of corneal abrasion. Bell’s palsy may
be treated with corticosteroid drugs to
reduce inflammation and speed recov-
ery. Re-routing or grafting of nerve tissue
may help people with palsies as a result
of injury or a tumour.
facial spasmAn uncommon disorder
in which there is frequent twitching of
facial muscles, which are supplied by the
facial nerve. Facial spasm affects pre-
dominantly middle-aged women and is
of unknown cause.
factitious disordersA group of disor-
ders in which a patient’s symptoms
mimic those of a true illness but which
have been invented by, and are control-
led by, the patient. There is no apparent
cause for a factitious disorder other
than a wish for attention. The most
common disorder of this type, Munch-
ausen’s syndrome, is characterized by
physical symptoms. In a second form,
Ganser’s syndrome, there are psycholo-
gical symptoms. These disorders differ
from malingering, in which the person
claims to be ill for a particular purpose,
such as obtaining time off work.
factor VOne of the blood proteins that
maintains the balance between the
blood clotting too easily or too slowly
after an injury. About 5 per cent of the
population have an inherited mutation
in the gene controlling factor V produc-
tion, known as factor V Leiden. They are
at increased risk of deep-vein thrombo-
sis(see thrombophilia), particularly if
they are taking the oral contraceptive
pill or go on long aircraft journeys.
factor VIIIOne of the blood proteins
involved in blood clotting. People with
haemophiliahave a reduced level of
factor VIII in their blood and, conse-
quently, have a tendency to abnormal
and prolonged bleeding when injured.
factor IXA protein in blood that plays
an important role in the clotting mecha-
nism. A deficiency of factor IX causes a
rare geneticbleeding disorderknown as
Christmas disease.
faecal impactionA condition in which
a large mass of hard faecescannot be
evacuated from the rectum. It is usually
associated with long-standing constipa-
tion. Faecal impaction is most common
in very young children and in the elder-
ly, especially those who are bedridden.
The main symptoms are an intense
desire to pass a bowel movement; pain
in the rectum, anus, and centre of the
abdomen; and, in some cases, watery
faeces that are passed around the mass.
Treatment is with enemasor by manual
removal of the faecal mass.
faecalithA small, hard piece of impac-
ted faeces that forms in a sac in the
wall of the intestine. A faecalith is
harmless unless it blocks the entrance
to the sac, causing diverticulitis, or to
the appendix, causing appendicitis.
faecesWaste material from the diges-
tive tract that is expelled through the
anus. Solidified in the large intestine,
faeces are composed of indigestible food
residue (dietary fibre), dead bacteria,
dead cells from the tract lining, intesti-
nal secretions, bile (which makes faeces
brown), and water.
faeces, abnormalFaeces that differ
from normal in colour, odour, consis-
tency, or content. Abnormal faeces may
indicate a disorder of the digestive sys-
temor related organ, such as the liver,
but a change in the character of faeces
is most often due to a change in diet.
Diarrhoeamay be due simply to anxi-
ety or may be caused by an intestinal
infection (see gastroenteritis); by an in-
testinal disorder such as ulcerative colitis
or Crohn’s disease; or by irritable bowel
syndrome. Loose stools may indicate
malabsorption. Constipationis generally
harmless but, if it develops unexpected-
ly, may be caused by a large-intestine
disorder such as colon cancer.
Pale faeces may be caused by diar-
rhoea, 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). Such faeces may be
oily, foul-smelling, and difficult to flush
away. Dark faeces may result from tak-
ing iron tablets. However, if faeces are
black, there may be bleeding in the
upper digestive tract.
Faeces containing excessive mucus are
sometimes associated with constipationFACIAL SPASM FAECES, ABNORMAL
F