Heat stroke

Introduction

Heat stroke - also known as hyperthermia syndrome - is a heat illness. Heat illness occurs when the body overheats. This occurs due to high temperatures combined with high humidity and physical exertion. The various heat illnesses - heat cramps, heat oedema, sunstroke, heat exhaustion or heat stroke - differ mainly in the severity of the symptoms.

Heat stroke patients have hot, reddened and dry skin (no sweat) and an accelerated heartbeat with low blood pressure. People with heatstroke should be moved to a cool place as soon as possible and should drink fluids. Heat stroke is the most severe form of heat illness. It is a medical emergency that can be fatal if left untreated.

Symptome

ISymptoms
In many cases, those affected underestimate the symptoms of heatstroke. These are similar to heat exhaustion, which is a precursor to heatstroke. However, the symptoms of heatstroke are more pronounced than those of heat exhaustion.

The symptoms of heat stroke are

• Fever > 40 °C (measured rectally)
• Confusion, hallucinations, seizures, loss of consciousness
• Gait disturbance, slurred speech
• Hot, dry, red skin, no sweat
• Accelerated heartbeat with low blood pressure
• Accelerated breathing, vomiting, diarrhoea

In heat stroke, the skin all over the body is red and feels hot and dry; in sunstroke, however, only the skin on the head is affected. In heat exhaustion, on the other hand, the skin is pale, cool and moist.

Experts distinguish between two main forms of heatstroke: classic and exertional heatstroke. Classic heatstroke occurs more frequently in older people - especially those with chronic illnesses or people who take medication or consume alcohol or drugs. Classic heatstroke can develop over several days as the water and electrolyte balance becomes increasingly unbalanced. Exertional heatstroke often develops as a result of exertion in the sun and heat and mainly affects people who are active outdoors.

Progression

If heatstroke is not treated, the patient's condition deteriorates - complications such as loss of consciousness, unconsciousness, shock or cerebral oedema (swelling of the brain due to water retention) can occur. Heatstroke can lead to death. A person with suspected heatstroke should never be left alone. Once the emergency services have been notified, the patient should be placed in the recovery position or, in the event of cardiac or respiratory arrest, chest compressions should be performed.

Causes

In the event of heatstroke, the body overheats; it can no longer regulate the heat. The risk of suffering a heat stroke increases if the outside temperature is 33 °C or higher if you are wearing warm clothing, exercising outdoors or not drinking enough. The same applies to fever or a lack of acclimatisation to the heat in the event of a sudden change in weather or travelling to hot climates. As the regulation of body temperature fails, perspiration is reduced. The lack of sweat can no longer cool the body through evaporation, resulting in a build-up of heat. The body temperature rises steadily. Above a core body temperature of 42 °C, many enzymes consisting of proteins lose their function and multi-organ failure can occur.

Heat also increases the cells' oxygen consumption, the heart beats faster and breathing speeds up. In addition, the blood vessels dilate so that the heat can be better transferred to the surface of the skin. As a result, blood pressure drops, which in extreme cases can lead to circulatory collapse.

People with chronic illnesses, young children and older people are more at risk of suffering heatstroke. Medication, alcohol and certain drugs can also affect the natural temperature regulation and the water and electrolyte balance, thus favouring heat illnesses. A pronounced obesity also makes you more susceptible to heat illness.

Diagnosis

The diagnosis of heat illness or heat stroke is obvious if those affected suffer from symptoms such as headaches, nausea, dizziness, light-headedness and severely reddened and hot-dry skin in hot and humid weather or intensive physical activity (combined with an increased body temperature, which is 40 °C or higher in heat stroke). The diagnosis is made based on the symptoms present and does not require any further laboratory tests. In principle, the diagnosis can also be made remotely using telemedicine, but heatstroke requires emergency treatment on-site. However, a mild heat illness can be treated well by telemedicine. It usually improves relatively quickly: an elevated body temperature should return to normal within an hour.

Treatment

The basic aim of treating heatstroke is to lower the elevated body temperature as quickly as possible. It is also important to recognise the first signs and take early signs of heat illness such as headaches, dizziness or muscle cramps seriously. Those affected should first get out of direct sunlight and away from the heat, get some rest and drink electrolyte-containing drinks. A doctor should be consulted if you feel very unwell, dizzy, have a high body temperature, vomit or if there is no rapid improvement after taking the above measures. If the body temperature exceeds 40 °C, heatstroke is suspected and must be treated in hospital as an emergency. Antipyretic medication is not effective for heatstroke.

Prevention

In principle, overheating of the body should be avoided by not exposing the body to excessively high temperatures. The best means of preventing heat stroke are the following measures:

• Avoiding direct and intense sunlight
• Wear loose and light clothing
• Move activities such as outdoor work or sport to the early morning or late evening hours
• Adequate intake of chilled non-alcoholic drinks such as mineral water, unsweetened teas or fruit juices diluted with water. Light food with a high fluid content is beneficial and refreshing. Fruit and vegetables with a high water content are particularly suitable.