INSOLATION.
Synonyms.—Sun-stroke; heat-stroke; thermic fever.
Definition.—The terms "insolation," "sun-stroke," "heat-stroke," and "ther mic fever" are applied to a series of symptoms occurring as the result of ex posure to undue heat of the whole or parts of the system, while the latter is in a condition of physical debility, and re sulting from intoxication by products of metabolism.
Symptoms.—The symptoms vary in intensity and nature, and three forms of insolation are recognized: heat-prostra tion, heat-apoplexy, and thermic fever.
HEAT-rnosTBATioN.—This form is frequently observed in cities during sum mer-heat, especially in persons in whom the powers of resistance have been weak ened by alcoholism, ill health, and over work. It is also the variety of insolation usually observed in soldiers, and is espe cially marked in men unused to march ing or who are laboring under a malarial toxaemia. These two associated varieties as described by de Santi illustrate thor oughly the series of phenomena most fre quently met with in active practice.
In the form characterized by indi vidual weakness, the man who has so far marched well becomes silent, unbuttons his coat, and, if asked, complains of violent headache and oppression; but he continues his march up to the moment when he becomes pale and falls, with convulsive movements, as if in an attack of epilepsy. The teeth are firmly closed, the insensibility is absolute, the respira tion difficult, the pulse small and irregu lar, and he often urinates involuntarily. A waxy pallor of the face appears also.
The patient moans, he streams with sweat, he drags in the rear, and if he continues his march he becomes still paler, while his lips become cyanosed; the jugular and temporal veins swell; the eyes become injected; the respira tions shallow and quick, until the suf ferer falls gently to the ground. He generally does not entirely lose con sciousness, and, when he is laid down and relieved of everything which inter feres with respiration, breathes deeply and quickly becomes himself again. Sometimes, however, on coming around. various nervous symptoms, usually not important, supervene.
The malarial form generally occurs in old soldiers who have long struggled with paludism. The man marches badly
on starting, but becomes more animated as he goes along. His face is red, he does not seem to feel the fatigue, but is thirsty; suddenly, as if struck down by a club, he falls face downward in a state of absolute coma. Here, generally the face is turgid, but sometimes it is pale. This state may last for hours,—twenty four or thirty-six,—and may terminate in death without recovery of conscious ness.
Series of 31 cases: in 19 the heat pre disposing to the attack was solar, in 11 it was artificial, while in 2 both factors were at work. The highest temperature attained was 112° F., more of the cases having temperatures, upon reception, be tween 110° and 111° F. than between any other two degrees. Twenty of the cases were unconscious, S were conscious, and 3 were partially conscious, while 4 were wildly delirious. Consciousness was maintained in every case where the temperature was below 10S° F., except in one, where the temperature was 102.4° F. The pupils in 24 cases were extremely contracted, in 5 they were natural, in 1 they were sluggish, while in 1 only they were dilated. Where the pupils were contracted there was also present unconsciousness. except in 3 eases, and in these the temperature was 106° or over. Convulsions occurred in but 6 cases. The pulse varied much in different eases, being invariably absent at the wrist, where the temperature reached 10S° P. Respiration in almost all eases was accelerated. Color of the face varied from flushed in the lighter cases, to livid and mottled in the cases with marked alteration in respiration and circulation. Involuntary evacuation of liquid, offensive stools was present in many of the cases, with the typical mousy, repulsive odor characteristic of these discharges. The longest time re quired to reduce temperature to within safe limits was within one hour, the average time being from ten to fifteen minutes. The prognosis could be made easily from the facility with which the temperature was reduced. The mortality in the whole series was 12 out of 31. The manner of death was, as a rule, by almost simultaneous cardiac and respira tory failure. F. A. Packard (Amer. Jour. Med. Sci., June, 'SS).