HAEMOLYTIC-URAEMIC SYNDROME
HAEMOSTASIS
H
may increase to a dangerous level, caus-
ing a risk of
kemicterus
(a type of brain
damage). Severely affected babies have
marked anaemia while still in the uterus.
They become swollen
(
hydrops fetalis)
and are often stillborn.
In mild cases, no treatment is neces-
sary. In other cases, the aim is to deliver
the baby before the anaemia becomes
severe, usually by
induction of labour
at
35-39 weeks' gestation. If the baby is
too young to be delivered safely, fetal
blood transfusions may be necessary.
After birth,
phototherapy
(light treat-
ment that converts bilirubin in the skin
into a water-soluble form that is more
easily excreted from the body) can help
to reduce
jaundice
.
An exchange blood
transfusion may be needed.
haemolytic-uraemic syndrome
A rare
disease in which red
blood cells
are
destroyed prematurely and the
kidneys
are damaged, causing acute
kidney fail-
ure
.
Thrombocytopenia
can also occur.
Haemolytic-uraemic
syndrome
most
commonly affects young children and
may be triggered by a serious bacterial
or viral infection. Symptoms include
weakness, lethargy, and a reduction in
the volume of urine.
Seizures
may occur.
Blood and urine tests can determine
the degree of kidney damage.
Dialysis
may be needed until the kidneys have
recovered. Most patients recover nor-
mal renal function.
haemophilia
An inherited
bleeding dis-
order
caused by deficiency of a blood
protein,
factor VIII
, which is essential
for blood clotting. Haemophiliacs suffer
recurrent bleeding, usually into their
joints, which may occur spontaneously
or after injury. The lack of factor VIII is
due to a defective gene, which shows a
pattern of
sex-linked inheritance
;
haem-
ophilia affects males in most cases.
Episodes of bleeding are painful and,
unless treated promptly, can lead to
joint deformity. Injury, and even minor
operations such as tooth extraction,
may lead to profuse bleeding. Internal
bleeding can lead to blood in the urine
or extensive bruises.
Haemophilia is diagnosed by
blood-
clotting tests
, and by
amniocentesis
or
chorionic villus sampling
in a fetus.
Bleeding can be prevented or controlled
by infusions of factor VIII concentrates.
haemophilus influenzae
A bacterium
(see
bacteria
) responsible for numerous
cases of the infectious diseases
epiglot-
titis
and
meningitis
.
haemoptysis
The medical term for
cough-
ing up blood
.
haemorrhage
The medical term for
bleeding
. (See also
haematoma
.)
haemorrhoidectomy
The surgical re-
moval of
haemorrhoids
. The procedure
is used to treat large, prolapsing, or
bleeding haemorrhoids.
haemorrhoids
Swollen veins in the
lining of the
anus
.
Sometimes these
veins protrude outside the anal canal,
in which case they are called prolapsing
haemorrhoids. Straining repeatedly to
pass hard faeces is one of the main
causes of haemorrhoids. Haemorrhoids
are also common during pregnancy and
just after childbirth.
Rectal bleeding and discomfort on
defaecation are the most common fea-
tures. Prolapsing haemorrhoids often
produce a mucous discharge and itch-
ing around the anus. A complication of
prolapse is
thrombosis
and
strangula-
tion
;
this can cause extreme pain.
Diagnosis is usually by
proctoscopy
.
Mild cases are controlled by drinking
plenty of fluids, eating a high-fibre diet,
and establishing regular toilet habits.
Rectal suppositories and creams con-
taining
corticosteroid drugs
and local
anaesthetics
reduce pain and swelling.
More troublesome haemorrhoids may
be treated by
sclerotherapy
,
cryosurg-
ery
, or by banding, in which a band is
tied around the haemorrhoid, causing it
to wither and drop off. A
haemorrh-
oidectomy
is
generally required for
prolapsing haemorrhoids.
haemosiderosis
A general increase in
iron
stores in the body. Haemosiderosis
may occur after repeated blood transfu-
sions or, more rarely, as a result of
excessive intake of iron.
haemospermia
The medical term for
blood in the semen (see
semen, blood
in the
).
haemostasis
The arrest of
bleeding
.
There are 3 main natural mechanisms
by which bleeding is stopped after
264
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