HYPOVITAMINOSIS
HYSTEROSCOPY
an early feature of
cerebral palsy
.
It occurs
in disorders of the spinal cord, such as
Werdnig-Hoffman disease
,
and in some
children who have
muscular dystrophy
.
hypovitaminosis
Any condition that re-
sults from insufficiency of
1
or more
vitamins.
Hypovitaminosis may be due to
an inadequate dietary intake or a diges-
tive disorder that causes
malabsorption
.
hypovolaemia
An abnormally low vol-
ume of blood in the circulation, usually
following blood loss due to injury, inter-
nal bleeding, or surgery. It may also be
due to loss of fluid from
diarrhoea
and
vomiting
.
Untreated, it can lead to
shock
.
hypoxia
An inadequate supply of
oxy-
gen
to the tissues. Temporary hypoxia
may result from strenuous exercise. More
serious causes include impaired breath-
ing (see
respiratory failure
),
ischaemia
,
and severe
anaemia
. A rare cause is
carbon
monoxide
poisoning. Severe, prolonged
hypoxia may lead to tissue death.
Hypoxia in muscles forces the muscle
cells to produce energy
anaerobically
,
which can lead to cramps. Hypoxia in
heart muscle may cause
angina pectoris
.
Hypoxia of the brain causes confusion,
dizziness, and incoordination, causing
unconsciousness and death if persistent.
Hypoxia can be assessed by using an
oximeter
to measure the oxygen concen-
tration of blood in the tissues. Severe
hypoxia may require
oxygen therapy
or
artificial
ventilation
.
hysterectomy
Surgical removal of the
uterus
. It is performed in order to treat
TOTAL HYSTERECTOMY
fibroids
, and cancer of the uterus (see
uterus, cancer
of) or cervix (see
cervix,
cancer of
). It may also be performed to
relieve heavy menstrual bleeding or
endometriosis,
and to remove a pro-
lapsed uterus (see
uterus, prolapse of
).
The most common type is a total hys-
terectomy, in which the uterus and
cervix are removed. Occasionally, the
fallopian tubes and ovaries are removed
as well. For cervical cancer, a radical
hysterectomy is performed, in which the
uterus, cervix and pelvic lymph nodes
are removed. Hysterectomy may be per-
formed through the vagina or through
an incision in the abdomen.
hysteria
An old-fashioned term encom-
passing a wide range of physical or
mental symptoms attributed to mental
stress. Symptoms formerly grouped un-
der this term are now included in the
more specific diagnostic categories of
conversion disorder
;
somatization disor-
der; dissociative disorders
;
and
factitious
disorders
. The term is still used loosely
to describe irrational behaviour.
hysterosalpingography
An
X-ray
pro-
cedure in which a dye
(
radiopaque
contrast medium) is introduced into the
cavity of the
uterus
via the
cervix
to
make the uterus and
fallopian tubes
visi-
ble on X-rays. Hysterosalpingography is
used to investigate
infertility
.
hysteroscopy
A technique that uses a
hysteroscope (see
endoscope)
to diag-
nose disorders, such as uterine
polyps
,
inside the
uterus
and
fallopian tubes
.
Hysteroscopy can be performed under
local
anaesthesia
. Minor surgery, such
as the removal of
fibroids
, may also be
carried out through the hysteroscope.
H
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