Treatment of heat exhaustion involves
rest and the replenishment of lost water
and salt. Prevention is usually by grad-
ual acclimatization to hot conditions,
heatstroke A life-threatening condition
in which overexposure to heat coupled
with a breakdown of the body's heat-
regulating mechanisms cause the body
to become dangerously overheated.
Heatstroke is most commonly caused
by prolonged, unaccustomed exposure
to the sun in a hot climate. Strenuous
activity, unsuitable clothing, overeating,
and drinking too much alcohol are
sometimes contributory factors.
Heatstroke is often preceded by
heat
exhaustion,
which consists of fatigue
and profuse
sweating.
With the onset of
heatstroke,
the sweating diminishes
and may stop entirely. The skin be-
comes hot and dry, breathing is shallow,
and the pulse is rapid and weak. Body
temperature rises dramatically and, with-
out treatment, the victim may lose
consciousness and even die.
Heatstroke can be prevented by grad-
ual acclimatization to hot conditions
(see
heat disorders).
If heatstroke deve-
lops, emergency treatment is required.
This consists of cooling the victim by
wrapping him or her in a cold, wet
sheet, fanning, sponging with water,
and giving salt solution,
heat treatm ent The use of heat to treat
disease, aid recovery from injury, or to
relieve pain. Heat treatment is useful
for certain conditions, such as ligament
sprains, as it stimulates blood flow and
promotes healing of tissues.
Moist heat may be administered by
soaking the affected area in a warm
bath, or applying a hot
com press
or
poultice.
Dry heat may be administered
by a heating pad, hot-water bottle, or by
a heat lamp that produces
infra-red
rays. More precise methods of adminis-
tering heat to tissues deeper in the
body include
ultrasound treatment
and
short-wave
diathermy
.
heel
The part of the
foot
below the
ankle
and behind the arch. The heel consists
of the
calcaneus
(heel bone), an under-
lying pad of fat that acts as a cushion,
and a layer of skin, which is usually
thickened due to pressure from walking.
HEATSTROKE
HEMIANOPIA
HEIMLICH MANOEUVRE
Heimlich manoeuvre A first-aid treat-
ment for
choking.
The sole aim of the
Heimlich manoeuvre is to dislodge the
material that is causing the blockage by
placing one fist, covered by the other,
just below the victim's rib cage, and
pulling sharply inwards and upwards to
give an abdominal thrust.
Helicobacter pylori A
bacterium
now
known to be the cause of most
peptic
ulcers
as well as a factor in
stomach can-
cer.
The bacterium is thought to damage
the mucus layer of the
stomach
and
duodenum,
allowing gastric acid to cause
ulceration. Treatment with
antibiotics
to
eradicate the infection has proved suc-
cessful in achieving long-term recovery
from peptic ulcers.
heliotherapy A form of
phototherapy
involving exposure to sunlight,
helminth infestation Infection by any
parasitic worm. (See
worm infestation
.)
hemianopia
Loss of half of the
visual
field
in each eye. Hemianopia may be
“homonymous” (in which the same side
of both eyes is affected) or “heterony-
mous” (in which the loss is in opposite
sides of the eyes). Visual loss may be
temporary or permanent.
Hemianopia is not due to a disorder
of the eyes themselves but results from
damage to the
optic nerves
or brain.
Transient homonymous hemianopia in
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