Heat Cramps.—Among those working in firerooms on board ships cruising in tropical waters, there is met frequently a condition characterized by cramps of the voluntary muscles, chiefly those of the extremities and abdomen.
Ill health and individual susceptibility appear to predispose toward attacks, but apparently hard physical labor, in conjunction with the environmental conditions, is the factor that determines the occurrence of the cramps. Their causation is usually attributed to dehydration of the tissues, or to accumulation of metabolic products, but some believe that they represent a condition differing from all other conditions recognized as being due to heat. Cases, probably identical in nature and having the same causative factors, have been noted as occurring among workers in steel-mills.
The cramps are usually preceded by fibrillation of the muscles later to be affected. When frankly spastic attacks are developed, they recur at intervals of from 2 to 10 minutes, and may be severe and very painful. The pupil is dilated, but so far as known, no other organs are involved. The cramps are commonly accompanied by signs of heat prostration. This, however, is not necessarily so, there often being absolutely no thermal disturbance.
The treatment is in general that of heat prostration. Immediate relief may be obtained by sudden slapping of an affected muscle. For mild cases, immersion in a warm bath is recommended. Apomorphine in sub-emetic doses is said to confer immediate relaxation.
Treatment
With heat stroke we have a condition in which every moment lost before the institution of proper treatment reduces the chances of recovery. The two important measures are reduction of temperature and elimination of toxic material. For the former ice packs or ice baths are the most efficient. When the temperature starts down it may fall with great rapidity and collapse result. Consequently when giving these ice packs or baths the treatment should be discontinued when the temperature by rectum reaches about 103°F., the patient then being removed from the bath and covered with a blanket. If the temperature again shoots up the ice bath can be repeated. Many have reported great benefit from the use of enemata cooled with ice. Some prefer to apply ice to the head and rub the body with pieces of ice. This can be carried out on a rubber sheet placed on a cot. If there is no ice available a sheet wet in dilute alcohol, plus the effects of a current of air from the electric fan or otherwise, may be tried. In a case with marked cyanosis venesection may be necessary. In asphyxial types of sun stroke prolonged artificial respiration is indicated.
Above has been noted the inefficiency of ice in reducing temperature and the far greater effect from evaporation, brought about by directing the current from a fan on the body covered with a wet sheet.
To promote elimination of toxic products venesection plus the use of intravenous injections of normal saline is the best treatment. In those terrible paralytic type cases which show a mortality of more than 50% it is well to think of acidosis and give slowly about a liter of a 1 or 2% solution of sodium bicarbonate. (See under treatment of cholera.) The use of alkaline enemata often gives good results, about a liter of a solution containing 2% of sodium chloride and 2% of sodium carbonate or bicarbonate.
As soon as possible after the more urgent hydrotherapeutic methods have controlled the case we should give calomel followed by salines. The coal tar products should be avoided as far as possible, from the danger of cardiac depression.
In the nonfebrile heat prostration the treatment is entirely eliminative and stimulant. The patient should be placed on his back in a cool shady place and tight clothing released, particularly about the neck. Rubbing the limbs as for any syncope-type affection, with hot water bottles if the collapse is marked, should be one line of treatment. Many give a little aromatic spirits of ammonia or whiskey but a hypodermic of strychnine would be better in a severe case.