SUNSTROKE, prostration due to ex posure to intense external heat. Such exposure may be to the direct or indirect rays of a trop ical sun or to the excessive heat of an engine room. In either case heat and physical exer tion combine to bring about the results. A high degree of humidity of the atmosphere is one of the most important features, since this hind ers free evaporation of fluid from the body which is one of the most important devices for cooling the body. Sunstroke is an old disease. Osier mentions that two instances are on record in the Bible and many of the ancients described it very well, confounding the severer forms with apoplexy. Two main types are seen — heat exhaustion and heat stroke. Other terms for heat stroke are isolation, thermic fever, coup de soleil.
Heat exhaustion is frequently seen among worlcmen who are exposed to the direct action of the sun. Bricklayers, drivers, farmers, etc., or firemen and stokers in large vessels, while in the midst of their work suffer from extreme prostration. There is great restlessness, muscu lar weakness, fainting spells and collapse, and often delirium. The surface of the body is usually cool and the temperature may be sub normal, 95° to 96° F., the pulse is small and rapid and unconsciousness rapidly develops. In heat stroke or thermic fever, the symptoms are quite different. Here marked physical exertion and direct exposure to the sun with high hu midity are important factors — in addition some form of alcoholic drink is being taken, notably ale, beer or whislcy. In the severe grades the patient may be suddenly struck down and die with rapid breathing, heart weakness and uncon sciousness. These cases are rare and frequently, on autopsy, turn out to be something else. The more common type commences with severe head ache, dizziness, a sense of weight in the head, and nausea and vomiting. If these signs are disregarded and the patient continues to march, if a soldier; or to stoke, if a stoker; or to work, if a laborer, symptoms of disordered vision develop; diarrhea and increased urina tion are present and then unconsciousness sets in. Seen in this condition the patient is usually flushed, the eyes blood-shot, the skin is hot and dry, the temperature, an important sign, is very high, 105° to 110° F., or in some cases even higher. The pulse is rapid and bounding; the
breathing is apt to be noisy, and the patient, apart from his very high temperature and dry may seem to be suffering from alcoholism. The pupils may be dilated or contracted and there may be an eruption on the skin. In these cases that end fatally the unconsciousness deep ens, the temperature mounts, convulsions and twitching occur, the breathing becomes very irregular and shallow. A gradual fall in tem perature and a return to consciousness are symptoms of recovery. Many patients after re covery have a permanent susceptibility to high temperatures.
It is important to distinguish between these two forms of heat poisoning as the treatment is radically different. In heat exhaustion there is vasomotor paralysis with cold wet skin and subnormal temperature, and patients should receive alcohol hot bottles and supportive treat ment. Heat stroke should be treated by cold and stimulants. The body should be drenched with cold water. The wrists and sides of the neck rubbed with icewater or ice, as the large arteries are here more readily reached and the blood more rapidly cooled. Icewater rectal injections are also useful to reduce the tempera ture rapidly and also to empty the bowels, an important indication. It may be necessary to immerse the patient directly into an ice bath. During this treatment careful readings of the clinical thermometer must be taken and as soon as the temperature sinks below 102,° to F., and stays there, the cold applications may be dis continued. Moderate venesection is not contra indicated, but that is a technical question for the physician to decide. In malarial countries, particularly below Mason and Dixon's line, quinine may be used to advantage to obviate possible malarial combinations. Coal tar anti pyretics are not advisable if signs of heart weakness are present. Of cardiac stimulants ammonia is the most serviceable, as it can be breathed by an unconscious patient. Sometimes chloroform is essential to control convulsions.
The mortality from heat exhaustion is about 9 per cent, whereas the high mortality of 25 per cent is recorded for heat stroke or thermic fever. Consult Manson, 'Tropical Diseases' (1900); 'Sunstroke' in 'Encyclopedia Medica' (1902); Wood, 'Thermic Fever, or Sunstroke> (1872).