(Heat Exhaustion: Sunstroke)
An affection produced by exposure to excessive heat. Two varieties are
recognized; heat exhaustion and thermic fever.
=Heat Exhaustion.=—This is caused by prolonged exposure to high
temperatures, combined with physical exertion. Fatigue, overeating,
alcoholic drinking, and poor sanitation predispose. This may occur
without exposure to the direct rays of the sun, the heat being
artificial, or in mid-summer, in close, confined rooms the same result
will be produced. There is vasomotor paralysis, the surface of the body
is usually cool, the temperature may be as low as 95 degrees F., while
the pulse is small and rapid.
=Sunstroke= or =Thermic Fever=.—This is usually caused by prolonged
work under the direct rays of the sun in a humid, very hot and sultry
atmosphere. This is caused by the action of the heat upon the heart
centers producing a paralysis of those centers.
=Pathologically=, rigor mortis develops early and is marked.
Putrefactive changes appear early, owing to the high temperature of
the cadaver. The various organs are deeply congested, the venous
engorgement is extreme in the cerebrum. There is rigid contraction of
the left ventricle; while the right is dilated and filled with blood.
The blood is fluid and dark. Parenchymatous changes take place in the
liver and kidneys.
In heat exhaustion with lowered temperature there is a paralysis of
the vasomotor center in the medulla, and the heat is dissipated more
rapidly than it is produced. In thermic fever the heat regulating
centers become paralyzed by the action of the excessive temperature and
more heat is produced, and less dissipated than normal.
=Symptoms.=—=Heat Exhaustion.=—This may occur gradually or suddenly
with a severe attack of faintness, pallor, dizziness, headache,
cold perspiration and sometimes blindness as the first symptoms.
Consciousness is rarely entirely lost. In severe cases there is more
permanent collapse. The pulse is rapid and feeble and there is great
restlessness and delirium. Under prompt treatment mild cases may
recover in a few hours, while in extreme cases death may occur almost
at once from heart failure.
=Thermic Fever.=—In some cases the patient is struck down, becomes
quickly unconscious, and may die within an hour, or death may be
almost instantaneous. In other cases there is pain in the head,
oppression, dizziness, nausea, vomiting and sometimes diarrhea or
frequent micturition. Soon unconsciousness sets in, the face is
flushed, the eyes injected, the breathing labored and there is a
temperature of from 105° to 110° F. The pulse is full and rapid, the
skin hot and dry and the pupils are contracted. There is usually
complete relaxation of the muscles, and in some cases there is
twitching and jactitation. Epileptiform convulsions are rare. In fatal
cases the coma deepens, the pulse becomes feeble, rapid and irregular,
the breathing hurried and shallow and death occurs in a few hours.
Favorable cases are indicated by a fall in the temperature and by the
return of consciousness. In these cases recovery may be complete. In
some cases the patient may never be able to stand even moderate degrees
of temperature, which often produce excitement, headache and pain in
the cervical region. Failure of the memory, and the loss of power to
concentrate the mind are sometimes sequelæ. Meningitis, epilepsy and
insanity are also sequelæ.
=Diagnosis.=—This presents little difficulty. The history and
circumstances preceding the attack are very important in making the
diagnosis. The diagnosis between heat exhaustion and sunstroke fever
is readily made. In heat exhaustion the temperature is =lowered=, the
pulse is feeble, consciousness is rarely completely lost; in sunstroke
fever the temperature is extremely =high=, there is usually complete
unconsciousness, and the pulse is full and rapid.
=Prognosis.=—This should be guarded, depending upon the severity of the
case.
=Treatment.=—In cases of =heat exhaustion= remove the patient to a
shady place and apply water to the face, chest and spine. Thoroughly
treat the upper cervical region, in order to control the impaired
vasomotor centers and nerves. If the temperature is below normal a hot
bath should be given. Keep the heart and lungs stimulated.
In =sunstroke=, place the patient in a recumbent position and loosen
all constricted clothing, and stimulate the heart’s action. The high
fever is to be met promptly. Place the patient in a bath of water,
to which add ice freely. The patient may also be rubbed with ice,
and ice water enemata may be employed. The muscles of the neck will
be found contracted, probably due to cerebral hyperemia. A thorough
relaxation of these muscles will be of great aid in equalizing the
vascular system. It is a good plan to thoroughly relax all the muscles
along the spinal column for the same purpose. When the temperature
nears normal the baths should be stopped. After the temperature has
been reduced place the patient upon a cot with ice to the head. The
cervical treatment should be repeated as often as necessary. The diet
of the patient should be liquid for a few days. Plenty of water and
stimulation of the kidneys and bowels will be found beneficial. The
sequelæ are to be treated according to the condition. Much can be done
for the sequelæ of heat exhaustion and sunstroke. Lesions will be found
corresponding to the regions involved. Deep contracted muscles are
common.