HYPHAEMA
HYPOHIDROSIS
H
a sensation of not being able to take a
full breath. Breathing into a paper bag
may help to reduce the symptoms in
people with anxiety.
hyphaema
Blood in the front chamber
of the
eye
,
usually caused by an injury
that ruptures a small blood vessel in
the
iris
or
ciliary body
.
Initially, there
may be blurred vision, but the blood
usually disappears completely within a
few days and vision is restored.
hypnosis
A trance-like state of altered
awareness characterized by extreme sug-
gestibility. Some psychoanalysts induce
a hypnotic state as a means of helping
patients remember and come to terms
with disturbing events. More often, hyp-
nosis is used to help patients to relax. It
may be useful in people suffering from
anxiety
,
panic attacks
,
or
phobias
,
or in
those wishing to correct addictive habits.
hypnotherapy
The use of
hypnosis
as
part of a psychological therapy.
hypnotic drugs
Drugs that induce sleep
(see
sleeping drugs
).
hypo-
A prefix meaning under, below, or
less than normal.
hypoaldosteronism
A rare deficiency
of the hormone
aldosterone
, which is
produced by the
adrenal glands
.
The
condition may be caused by damage or
disease affecting the adrenal glands. It
may produce weakness, and is treated
by the drug fludrocortisone.
hypocalcaemia
An abnormally low level
of
calcium
in the blood. The most com-
mon cause is
vitamin D
deficiency. Rarer
causes include chronic
kidney failure
and
hypoparathyroidism
.
In mild cases, hypo-
calcaemia is symptomless; in severe
cases, it leads to
tetany
. It may also result
in bone softening, causing
rickets
in chil-
dren and
osteomalacia
in adults.
hypochondriasis
A person's unrealis-
tic belief that he or she is suffering
from a serious illness, despite medical
reassurance. Hypochondriacs worry con-
stantly about their health and interpret
any symptom, however trivial, as evi-
dence of disease.
Hypochondriasis may be a complica-
tion of other psychological disorders,
including
phobia
,
obsessive-compulsive
disorder
,
generalized a ^ iety disorder
,
and brain diseases such as
dementia
.
Other factors include social stresses
and personality type. Where possible,
treatment is of the underlying mental
disorder. Hypochondriasis without an
underlying cause is difficult to treat.
hypochondrium
The region on each
side of the upper abdomen, situated
below the lower ribs.
hypoglossal nerve
The 12th
cranial
nerve
,
which controls tongue movement.
hypoglycaemia
An abnormally low level
of
glucose
in the blood. Almost all cases
of hypoglycaemia occur in people with
diabetes mellitus
, in whom the
pancreas
fails to produce enough
insulin
, result-
ing in an abnormally high level of
glucose. To lower the blood glucose
level,
hypoglycaemic drugs
or insulin
are given. Too high a dose of either can
reduce the blood glucose to too low a
level. Hypoglycaemia can also occur if a
diabetic person misses a meal or takes
strenuous exercise. Rarely, the condi-
tion can result from drinking too much
alcohol or from an insulin-producing
pancreatic tumour.
The main symptoms include
sweating
,
hunger, dizziness, trembling, headache,
palpitations
, confusion, and sometimes
double vision. Behaviour is often irra-
tional and aggressive.
Coma
may occur
in severe cases. Hypoglycaemia may
also be the cause of seizures and jittery
behaviour in newborns.
Sugar should be eaten at the first sign
of a diabetic attack. An injection of either
glucose solution or the hormone gluca-
gon may be given in an emergency.
hypoglycaemics, oral
A group of
anti-
diabetic drugs
that are used to lower
blood glucose. Too high a dose may
provoke the onset of
hypoglycaemia
.
hypogonadism
Underactivity of the
tes-
tes
or
ovaries
. Hypogonadism may be
caused by disorders of the gonads or a
disorder of the
pituitary gland
that causes
deficient production of
gonadotrophin
hormones
. In men, hypogonadism causes
the symptoms and signs of
androgen
hormone
deficiency; in women, it causes
those of
oestrogen
deficiency.
hypohidrosis
Reduced activity of the
sweat glands
.
Hypohidrosis is a feature
of hypohidrotic ectodermal dysplasia, a
rare, inherited, incurable condition that
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