FIBRIN
F
potential
to
be
serious
because
it
impairs the ability of the chambers to
contract efficiently.
fibrin
A substance that is produced in the
blood
during
the
process
of
blood
clotting
.
Fibrin is formed from a dis-
solved protein called
fibrinogen
.
It forms
long
filaments that bind
clumps
of
platelets
and other blood cells into a
mass that plugs the bleeding point,
thereby preventing further blood loss.
fibrinogen
A protein that is present in blood and
w hich is converted into
fibrin
during
the
blood clotting
process.
fibrinolysis
The breakdown of
fibrin
,
the principal
component of any blood clot. Fibrin is
a stringy protein that is formed in
blood as the end product of coagula-
tion (see
blood clotting
) .
Blood also
contains a fibrinolytic
system, w hich is activated in parallel
w ith the coagulation system when a
blood vessel is damaged. The fibrino-
lytic system prevents the formation of
clots
in
undamaged
blood
vessels,
thereby preventing a blockage in these
vessels, and it acts to dissolve a clot
once healing of a broken blood vessel
w all has taken place.
Thrombosis
(abnormal formation of
blood
clots)
occurs in situations in
w hich there is a disturbance in the nor-
mal balance between the coagulation
and fibrinolytic mechanisms.
Drugs
that
achieve
the
effect
of
fibrinolysis (see
thrombolytic drugs
)
can
be used to treat certain disorders, such
as
pulmonary embolism
and
myocardial
infarction
,
in w hich blood clots block
the circulation.
fibrinolytic drugs
Another name for
thrombolytic drugs
,
w hich are used to dissolve blood clots.
fibroadenoma
A noncancerous fibrous tumour most
commonly found in the breast. Fibro-
adenomas occur most often in women
under the age of 3 0
and in black
women. M ultiple tumours may devel-
op in one or both breasts.
Fibroadenomas
of the
breast
are
painless, firm, round lum ps that are
usually between
1
and 5 cm in diame-
ter and movable. Although the cause of
fibroadenomas is not fully understood,
their
development
in
the
breast
is
believed to be linked to the sensitivity
of breast tissue to female sex hor-
mones. The lum ps tend to grow more
quickly
during
pregnancy,
probably
due to the increased levels of female
sex hormones.
A sample of tissue from the lump is
removed and examined to confirm the
diagnosis (see
biopsy
) .
Fibroadenomas
are harmless and do not require treat-
ment unless they become very large or
cause discomfort.
fibroadenosis
An
outdated
term
for
the
general
lumpiness that
is
a norm al feature
of some
wom en’s
breasts.
Cyclical
changes in hormone levels often lead
to the appearance of lumps in the
breasts, and the lumpiness is more
obvious before a menstrual period.
Lumpy breasts do not increase the
risk of developing breast cancer. H ow -
ever, a new solitary, discrete
breast lump
should be assessed by a doctor to rule
out the possibility of breast cancer.
(See also
mammary dysplasia
. )
fibrocystic disease
A term that is used to refer either to
the
inherited
disorder
cystic fibrosis
or to general lumpiness of the breasts
(see
fibroadenosis
) .
fibroid
A
slow-growing
and
noncancerous
tumour that is found in the w all of the
uterus
.
A
fibroid
is
composed
of
smooth muscle and
connective tissue
.
There may be one or more fibroids,
and they may range in size from as
small as a pea to as large as a grape-
fruit. Fibroids are common, appearing
most often in women between the
ages of 3 5 and 45.
CAUSE
The cause of a fibroid is thought to be
related to an abnormal response to
oes-
trogen hormones
.
Oral contraceptives
that
contain oestrogen can cause enlarge-
ment
of fibroids,
as
can
pregnancy
.
Decreased
production
of
oestrogen
after the
menopause
usually causes any
fibroids to shrink.
SYMPTOMS
In many cases, there are no symptoms.
If a fibroid enlarges and projects into
the cavity of the uterus, it may cause
heavy or prolonged periods. A large
fibroid may exert pressure on the blad-
der, causing frequent passing of urine,
or on the bowel, causing backache or
constipation. Fibroids that distort the
uterine cavity may cause recurrent
mis-
carriage
or
infertility
.
Rarely, a fibroid
may become twisted, resulting in sud-
den pain in the lower abdomen.
DIAGNOSIS AND TREATMENT
Fibroids that do not cause symptoms
are often discovered during a routine
pelvic examination.
Ultrasound scanning
can confirm the diagnosis.
Small, symptomless fibroids gener-
ally require no treatment, but regular
examination may be needed to assess
growth. Surgery or microwave
endome-
trial ablation
(MEA)
is
required
for
fibroids causing serious symptoms. In
some cases, they can be removed with
a
hysteroscope
(a
tubelike
viewing
instrument with surgical attachments)
under general anaesthesia (see
anaes-
thesia, general
) ,
leaving
the
uterus
intact.
Removal
of fibroids
usually
results in regained fertility. Sometimes,
however, a
hysterectomy
(removal of the
uterus) is required.
fibroma
A noncancerous tumour of the cells
that form
connective tissue
.
For exam-
ple, a neurofibroma is a tumour of the
cells that surround nerve fibres (see
neurofibromatosis
) .
Treatment
is
only
needed if there are symptoms.
fibromyalgia
Pain
and
stiffness
in
the
muscles,
w hich is often associated with distur-
bance of sleep. Fibromyalgia is most
common in women aged between 40
and 60 years. The condition is also
known
as
chronic widespread
pain
(CW P) and was formerly referred to as
fibrositis. Medical investigation usually
fails to reveal any underlying cause
and, for this reason, some doctors do
not recognize fibromyalgia as a medical
condition. However, the lives of affected
people are often severely disrupted.
308
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