VOMITING
VON WILLEBRAND'S DISEASE
be present from birth or may be a result
of
adhesions.
It requires emergency
treatment, usually by surgery.
vomiting Involuntary forcible expulsion
of stomach contents through the mouth.
Vomiting may be preceded by nausea,
pallor, sweating, excessive salivation,
and slowed heart-rate. It occurs when
the vomiting centre in the
brainstem
is
activated by signals from 1 of 3 places
in the body: the digestive tract; the bal-
ancing mechanism of the inner
ear
; or
the brain, either due to thoughts and
emotions or via the part of the brain
that responds to poisons in the body.
The vomiting centre sends messages to
both the
diaphragm,
which presses
down on the stomach, and the abdomi-
nal wall, which presses inwards, thereby
expelling the stomach contents upwards
through the
oesophagus.
Vomiting may be due to overindulgence
in food or alcohol, is a common side
effect of many drugs, and may follow
general
anaesthesia
. Vomiting is also
common in gastrointestinal disorders
such as
peptic ulcer,
acute
appendicitis,
gastroenteritis,
and
food poisoning.
Less
commonly, it is due to obstruction (see
pyloric stenosis; intussusception)
or a tu-
mour of the digestive tract. It may also
be due to inflammation (see
hepatitis
;
pancreatitis
;
cholecystitis
).
Other possible causes are pressure on
the skull (see
encephalitis; hydrocepha-
lus; brain tumour; head injury; migraine),
conditions affecting the ear's balancing
mechanism (see
Meniere's disease; laby-
rinthitis; motion sickness),
and hormonal
disorders (see
Addison's disease).
Vomiting may be a symptom of keto-
acidosis in poorly controlled
diabetes
mellitus
. It may also be a symptom of an
emotional problem or be part of the
disorders
anorexia nervosa
or
bulimia.
Persistent vomiting requires medical
investigation. Treatment depends on the
cause.
Antiemetics
may be given. (See also
vomiting blood; vomiting in pregnancy.)
vomiting blood A symptom of bleed-
ing from within the digestive tract.
Vomiting blood may be caused by a
tear in the lower oesophagus (see
Mal-
lory-Weiss syndrome),
bleeding from
oesophageal varices
, erosive
gastritis
,
peptic ulcer
, or, rarely,
stomach cancer
.
Blood can also be vomited if it is swal-
lowed during a nosebleed. Vomited
blood may be dark red, brown, black, or
may resemble coffee grounds. Vomiting
of blood is often accompanied by the
passing of black, tarry faeces.
The cause of vomiting blood is investi-
gated by
endoscopy
of the oesophagus
and stomach, or by
barium X-ray exami-
nations
. If blood loss is severe,
blood
transfusion
, and possibly surgery to
stop the bleeding, may be required.
vomiting in pregnancy Nausea and
vomiting in early
pregnancy
are com-
mon and are most likely to be caused
by changes in the hormone levels. Vom-
iting occurs most frequently in the
morning, but it may occur at any time. It
is sometimes precipitated by stress,
travelling, or food.
In rare cases, the vomiting becomes
severe and prolonged. This can cause
dehydration, nutritional deficiency, altera-
tions in blood acidity, and weight loss.
Immediate hospital admission is then
required to replace lost fluids and
chemicals by
intravenous infusion
, to
rule out any serious underlying disor-
der, and to control the vomiting.
von
Recklinghausen's
disease An-
other name for
neurofibromatosis
.
von Willebrand's disease An inheri-
ted lifelong
bleeding disorder
similar to
haemophilia
. People with the condition
have a reduced concentration in their
blood of a substance called von Wille-
brand factor, which helps
platelets
in
the blood to plug injured blood vessel
walls and forms part of
factor VIII
(a
substance vital to blood coagulation).
Symptoms of deficiency of this factor
include excessive bleeding from the
gums and from cuts and nosebleeds.
Women may have heavy menstrual bleed-
ing. In severe cases, bleeding into joints
and muscles may occur.
The disease is diagnosed by
blood-
clotting tests
and measurement of blood
levels of von Willebrand factor. Bleeding
episodes can be prevented or controlled
by desmopressin (a substance resem-
bling
ADH).
Factor VIII or concentrated
von Willebrand factor may also be used
to treat bleeding.
V
591
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