Heat related illnesses occur due to increase or rise in environmental temperature above 32? C and at high relative humidity of atmosphere.
Heat related illnesses are of five types which are as follow-
1. Heat cramps.
2. Heat oedema.
3. Heat exhaustion.
4. Exertional heat injury.
5. Heat stroke.
1. Heat cramps-
Heat cramps are caused due to hyponatraemia which results from loss of sodium in the sweat coupled with inadequate sodium replacement. Hyperventilation producing respiratory alkalosis and mild hypokalaemia may cause heat cramps.
In heat cramps, there occurs painful spasm of skeletal muscles, both of extremities and abdomen and inthose muscles which have been predisposed to excessive exercise.
2. Heat oedema-
It occurs as ankle and wrist swelling in the first few days of heat exposure, which get resolved within a few days.
3. Heat exhaustion-
It usually occurs in elderly patients and occurs due to fluid and electrolyte losses coupled with inadequate replacement. It causes fatigue and vertigo along with increased thirst. Loss of appetite is there along with nausea and vomiting. It also causes anxiety, headache, hyperventilation and muscular incoordination. Skin is cold and there is dilated pupils and high pulse rate with low blood pressure.
4. Exertional heat injury-
It occurs in people or workers who work in hot and humid weather or environment for example, in long distance runners. In it there occurs headache, chills, hyperventilation, nausea, vomiting and muscular incoordination along with
Excessive sweating is there along with high body temperature with tachycardia and low blood pressure. Hypernatraemia is there along with hypocalcaemia and hypophosphataemia and hypoglycaemia.
5. Heat stroke-
Heat stroke is characterized by hyperthermia and neurological symptoms. It is of two types-
a) Exertional heat stroke- is that type of heat stroke which occurs due to increased endogenous heat production. It occurs in healthy, young people usually during the acclimatisation who exert in hot environment.
b) Classic heat stroke- which occurs due to impairment of heat dissipation. It occurs in elderly persons with underlying predisposing conditions during hot weather.
In heat stroke, there occurs headache, hyperventilation, vertigo and abdominal distress before losing consciousness. Hyperthermia is there with body temperature more than or above 41.1?C. Skin is dry but there is no sweating. Tachycardia is there with low blood pressure, stupor or coma in severe cases. Respiratory alkalosis, metabolic acidosis and proteinuria are there along with ECG changes.
Do you know about- Causes of Acute Onset Dyspnoea
References- Book- Medicine by Methew and Parveen Aggarwal