At what temperature is a patient considered hyperthermic?

The condition where the body cannot regulate the temperature, resulting in elevated body temperature, is called hyperthermia or overheating. Here, the body produces more heat than what gets dissipated. If the temperature rises extremely, it can result in fatal complications and require immediate medical attention. Around 5 lakh deaths are caused every year due to this condition. The major causes of hyperthermia are heatstroke and severe adverse reactions to drugs that affect the central nervous system.

Hyperthermia and fever are different. Hyperthermia is the opposite of hypothermia, where the body’s temperature falls. 98.6 °F or 37 °C is the average body temperature. Hyperthermia is when the body temperature is above 100.4 °F or 38 °C, and when the body temperature is lower than 95 °F or 35 °C, it is called hypothermia. Temperatures above 104 °F or 40 °C are considered severe hyperthermia.

What Are the Stages and Symptoms of Hyperthermia?

The symptoms of hyperthermia can occur in the following stages. You might or might not develop all of the listed stages or symptoms:

1) Heat Stress - The body’s temperature rises, but the person does not sweat, and cooling off of the body does not take place. This can lead to heat exhaustion and heatstroke. The symptoms include:

• Feeling uncomfortably hot.

• Dizziness.

• Headache.

• Tiredness.

• Nausea.

• Thirst.

2) Heat Fatigue - A person who is working under extremely hot weather, develops physical discomfort and psychological stress. If you are not used to working in hot conditions, you might be susceptible to heat fatigue. The symptoms are:

• Feeling hot.

• Thirsty.

• Tired.

• Difficulty concentrating.

• Loss of coordination.

3) Heat Syncope - A person faints, his or her blood pressure falls, and the blood circulation to the brain is cut off temporarily due to heat. Heat syncope commonly occurs when you exert yourself in a hot climate. People who take beta-blockers for hypertension are more prone to heat syncope. You might experience:

• Dizziness or lightheadedness.

• Fainting.

4) Heat Cramps - Involuntary muscle spasms during intense exercise in a hot environment. They usually result from an electrolyte imbalance. The muscles of the abdomen, arm, and leg are most commonly affected.

5) Heat Edema - Swelling in the hands, legs, or ankles because of sitting or standing in the heat for a long time. Fluid gets filled in the extremities. Edema is because of the resorption of sodium through the kidneys into the blood.

6) Heat Rash - Some people get red bumps on the skin if they spend a lot of time in the sun. These rashes are mainly seen in the skin underneath clothing that becomes wet due to sweat.

7) Heat Exhaustion - In this stage, the body cannot cool itself any longer and is the most serious stage. The symptoms experienced are:

• Sweating profusely.

• Dizziness.

• Thirst.

• Weakness.

• Concentration problems.

• Cool and clammy skin.

• Rapid pulse.

When to Consult a Doctor for Hyperthermia?

As an increase in body temperature can be fatal, it is important to get immediate medical help. In case of the following signs and symptoms, consult a doctor immediately:

1. Fainting.

2. Irritability.

3. Coordination problems.

4. Flushed skin.

5. Rapid pulse.

6. Increase in body temperature.

Who Is at Risk for Hyperthermia?

Working in extremely hot climates increases the risk of hyperthermia. The following people are at risk:

• Construction workers.

• Farmers.

• Athletes.

• Firefighters.

• Children who play outdoors.

• Older adults.

Some health conditions can also increase the risk of hyperthermia. They are:

• Dehydration.

• Impaired circulation.

• Inefficient sweat glands.

• Heart or kidney diseases.

• Being overweight or underweight.

• Consuming alcoholic beverages.

• Hypertension.

• Medications, such as diuretics, tranquilizers, sedatives, and blood pressure drugs, can reduce sweating.

What Causes Hyperthermia?

The following are the causes of hyperthermia:

1. Increased heatwaves or humidity.

2. Excess heat production due to overexertion, malignant hyperthermia, and other conditions.

3. Poor heat dissipation due to reduced sweating or humid environment.

Typically, proper temperature is maintained by sweating and peripheral vasodilation (constriction of blood vessels in the hands and feet). When the climate is hot, these cooling mechanisms are insufficient, leading to heat-related illnesses.

Are Fever and Hyperthermia the Same?

The hypothalamus, a part of the brain, regulates the body’s temperature. It maintains the body temperature at around 98.6 °F (37 °C). In the case of infection, the hypothalamus makes the body hot (fever) to make the environment hostile for the pathogens. Once the pathogen gets eliminated, the body temperature gets back to normal.

In hyperthermia, the body tries to adjust to the hot environment. If the body finds it hard to keep its body cool despite the hot climate, the body’s temperature climbs in response.

A fever can be treated with Paracetamol or other medicines, but it is not effective in hyperthermia.

How Is Hyperthermia Managed?

If you develop signs of hyperthermia, make sure you:

• Move to a cooler location with air conditioning, if possible.

• Drink sports drinks containing electrolytes or water.

• Take a cool shower.

• Ice bags can be kept under your arms or the groin area.

The treatment for different stages of hyperthermia are:

For heat stress, fatigue, and cramps - Move to a colder area and take a rest. Drink water or other fluids containing electrolytes to prevent dehydration. Electrolyte liquid contains calcium, sodium, and potassium, regulating your heart rate and muscle health. When you start feeling dizzy, put your legs up. Move to a more relaxed location.

Edema or swelling subsides over time. Make sure you are well hydrated and put your feet up. Heat rashes disappear on their own when you cool down. The rash can get infected, so avoid scratching them. If they are infected, you might have to apply a topical antibiotic cream. Heatstroke is a medical emergency that needs hospitalization and immediate medical attention.

How to Prevent Hyperthermia?

You can prevent hyperthermia by:

1. Do not let your children play outdoors in extremely hot conditions.

2. Take breaks in a cool place frequently.

3. If not absolutely necessary, stay indoors.

4. Keep drinking water and stay hydrated.

5. Wear loose-fitting cotton clothes outdoors.

For more information on hyperthermia, consult a doctor online now.

Hyperthermia refers to a group of heat-related conditions characterized by an abnormally high body temperature. In lay terms it is "overheating". It is an abnormally high body temperature caused by a failure of the heat-regulating mechanisms of the body to deal with the heat coming from the environment.

• Hyperthermia is defined as a body temperature greater than 40°C and consists of a spectrum of conditions that range from mild (heat oedema, heat rash) to life-threatening (heat stroke).
• Risk for these conditions can increase with the combination of outside temperature, general health and individual lifestyle.
• In humans, core body temperature ranges from 95.9°F to 99.5°F (35.5°C to 37.5°C) during the day.[1]

See also Heat Illness in Sports

Levels of Heat Illness[edit | edit source]

Patient is being sprayed with cool water,1943.

Heat-related illnesses start out mildly uncomfortable and progress all the way to life-threatening. The conditions are, from least serious to most serious: heat oedema, heat rash, heat syncope, heat cramps, heat exhaustion and heatstroke.

1. Heat Oedema and Heat Rash: Heat oedema and heat rash are both the mildest sorts of heat illness. Heat oedema may occur as the body tries to dissipate heat by vasodilation and a shift of blood flow to the skin. This mostly happens in the lower extremities as fluid creates inflammation in the feet and ankles. Heat rash (also known as prickly heat or miliaria Rubra) is a pinpoint red rash that forms on the skin that was covered by clothing. This generally occurs in areas that have a higher concentration of heat glands, such as the trunk and groin, and is caused by the rise in sweat saturating the clothing and skin surface clogging sweat ducts.
2. Heat Syncope: Heat syncope, or fainting caused by heat, can happen during excessive heat exposure because blood is being shunted to the skin and extremities. Rapid changes in body position (frequently seen in sitting to standing, or bending over and standing back up) may lead to a temporary change in blood pressure that causes an individual to faint. Most athletes recover quickly once laid flat, which allows blood flow to normalise. That being said, falling due to a rapid loss of consciousness could lead to a concussion, and an athlete who faints due to heat should be evaluated before being allowed to continue training or competing.
3. Heat Cramps: Heat cramps or muscle spasms have been notoriously linked with dehydration and electrolyte imbalances over the years. However, exercise-associated muscle cramps are more commonly related to a wider range of variables like fatigue and muscular imbalances. Although harmful to performance, exercise-associated muscle cramps are generally harmless to our health and most ordinarily occur on one side of the body. If experiencing bilateral, or both sides, cramping or full body cramping, this is often linked to a more serious condition like extreme dehydration or hyponatremia (depleted electrolytes from excessive water consumption) and should be immediately addressed by a physician or the medical team at the event.
4. Heat Exhaustion: Heat exhaustion should be taken seriously and managed quickly because it can advance to severe and potentially life-threatening conditions like heat stroke. Heat exhaustion classically presents with fatigue, dizziness, excessive sweating, nausea, vomiting, headache, fainting, weakness, and cold, clammy skin. An athlete with exhaustion typically still has normal cognitive and neurological function. They should be able to answer questions about their condition, where they are, who they are, etc.
5. Heat Stroke: Heatstroke is characterized by a core body temperature >104°F (40°C) with altered central nervous system functions such as irritability, confusion, combativeness, or maybe worse, loss of consciousness. Hot and dry skin is a sign of heat stroke, but it is important to understand an athlete may be sweating and still have heat stroke. The altered CNS function is the hallmark difference between heat exhaustion and heat stroke, but when unsure, treat the situation as if the athlete has heat stroke. Athletes showing signs of heat stroke have to be treated by medical professionals as soon as possible. It should be stressed that heat stroke is incredibly severe and may cause death if not treated quickly[2].

People at risk[edit | edit source]

• The Elderly
• Being dehydrated.
• Age-related changes to the skin such as impaired blood circulation and inefficient sweat glands.
• Heart, lung and kidney diseases, as well as any illness that causes general weakness or fever.
• High blood pressure or other conditions that require changes in diet. eg people on salt-restricted diets may be at increased risk. However, salt pills should not be used without first consulting a doctor.
• Reduced sweating, caused by medications such as diuretics, sedatives, tranquilizers and certain heart and blood pressure drugs.
• Taking several drugs for various conditions. It is important, however, to continue to take prescribed medication and discuss possible problems with a physician.
• Being substantially overweight or underweight.
• Drinking alcoholic beverages.[3]
• Traumatic brain injured patients
• Exercise overdose

Management[edit | edit source]

If you suspect that someone is suffering from a heat-related illness:[3]

1. Get the person out of the heat and into a shady, air-conditioned or other cool place. Urge them to lie down.
2. If you suspect heat stroke, call emergency number.
3. Encourage the individual to shower, bathe or sponge off with cool water.
4. Apply a cold, wet cloth to the wrists, neck, armpits, and/or groin. These are places where blood passes close to the surface of the skin, and the cold cloths can help cool the blood.[3]
5. If the person can swallow safely, offer fluids such as water, fruit and vegetable juices, but avoid alcohol and caffeine

Cooling Technique[edit | edit source]

Indications for cooling include any signs of heat-related illness in the presence of an elevated body temperature. Previously, heat-related illness has been defined as core body temperature greater than 40 C. However, any elevation above normal body temperature in asymptomatic patient is an indication to consider cooling.

• The objective is to rapidly decrease the temperature below 40 C, with the final goal of reaching normal range (36°C to 38°C).
• It is important to note if the patient's other vital signs, like hemodynamic instability, indicate severe heat stroke, in which case, rapid cooling is the most crucial intervention to stabilize the patient.[4]

Reference[edit | edit source]