Fever

Fever

Fever is very common, but is not considered a disease in itself. Despite the fact that elevated body temperature in the form of fever is a natural part of the body's defense against infections, in some cases it may be necessary to treat.

What is fever?

Fever is defined as a body temperature higher than 38 °C, measured in the rectum. The body's temperature is regulated from the thermoregulatory center in the hypothalamus in the brain. This center receives information from the whole body about the temperature. If we are too hot, measures are initiated to lower the temperature. In the event of a fever, this "thermostat" in the body is set to too high a temperature, which results in a fever. Fever is very common, and the reason for many doctor's consultations.

Causes of fever

Fever is not a disease, but a symptom. When our immune system starts working, some cells release fever-causing substances called pyrogens. Fever can therefore be caused by increased activity in the immune system.

Common viral infections are the most frequent cause of fever. The body is usually able to deal with this type of infection well on its own. Other causes of fever can be:

• Bacterial infections

• Inflammations

• Burns and other major damages

• Autoimmune diseases

• Allergic reactions

• Drug reactions

When do you have a fever?

You have a fever when you measure a body temperature higher than 38 ° C. A high fever is considered a body temperature higher than 40 ° C. Body temperature can otherwise vary with time of day, age and physical activity. What is considered normal body temperature depends on where you measure, but 37 °C is generally considered normal body temperature.

Normal body temperature depending on the measurement location:

• Rectum – 37.1 °C

• Oral – 36.4 °C

• The ear – 36.6 °C

Symptoms of fever

• Laxity and weakness

• Unwellness

• Aching muscles

• Drowsiness

• Headache

• Decreased appetite

• Chills when the fever rises

• Sweating when the fever subsides

How long does a fever last?

Fever can last from a few hours to several days. How long a fever lasts depends on which disease is responsible for the fever, but most often the fever is short-lived. Treatment with antipyretics can relieve symptoms from fever, but will not affect how long the fever lasts.

How should fever be measured?

Fever can be measured in several ways. Taking the temperature rectally gives the most accurate answer. There is not always a need for completely precise measurements, but in those cases, you should measure rectally. However, it is often sufficient to know approximately what the temperature is.

• Rectum - gives the most precise measurements. It is important that small children are calm during the measurement to avoid injury

• The pan - simple way to measure temperature, but gives an imprecise answer

• Under the tongue - simple and straightforward method, suitable for adults and older children. The temperature of the mouth is affected by hot and cold drinks - therefore avoid drinking 15 minutes before measuring the temperature. The temperature in the mouth is approximately 0.5 °C lower than measured in the rectum

• The armpit - dependent on the thermometer being completely still during the measurement and the armpit being completely closed to give a good result. Here, too, the temperature is on average 0.5 °C lower than measured in the rectum

• Ear - should measure both the right and left ear, and use the average of these measurements as a measure of temperature. Generally not recommended for children

The body's temperature varies throughout the day. It is lowest in the morning and highest in the evening. It is a good idea to measure your own body temperature relatively often so that you know your normal temperature. This also applies to small children - then it is easier to know when you have a fever.

What helps against fever?

Drink plenty. With a fever, fluid loss is higher than usual

Avoid too many clothes or lots of blankets and duvets

Be careful not to keep it too hot inside

People with a high fever should take it easy and stay in bed

Treatment for fever

Fever is an important reaction because the body's immune system works more efficiently at an increased temperature. Therefore, it is not always appropriate to give antipyretic medicine, especially not in the case of a low to moderate fever. Fever-reducing medicine can be used when you have symptoms associated with a fever.

Antipyretic for adults: There are several different preparations that work against fever. These medicines also act as pain relievers. Preparations with paracetamol (Paracet, Panodil, Pinex) are recommended as first choice. Paracetamol has few side effects with normal use and is tolerated by most people. Medicines in the group NSAIDs (non steroidal anti-inflammatory drugs) can also be used as antipyretics. Examples of NSAIDs are ibuprofen and acetylsalicylic acid.

Antipyretic for children: Preparations with paracetamol are also recommended as first choice for children. Strength and dosage adapted to the child's weight and age are important when choosing antipyretic medicine for children. In addition, there are several different formulations suitable for children that you can choose from. Children with fever should not be treated with acetylsalicylic acid.

Remember to read the package insert before using non-prescription medicines.

Is fever dangerous?

Most people who are otherwise healthy and fast tolerate fever well. Fever is a natural reaction when illness occurs, and can help kill or inhibit the growth of bacteria, viruses and fungi. A high fever does not necessarily mean that you are seriously ill. Children in particular can have a relatively high fever without being in bad shape. However, a high fever above 41 °C can be a sign of serious illness. It is also at this temperature that the fever itself is considered negative. Fever as a result of infection rarely rises above 41 °C.

Fever in young children

Small children get a fever more easily than adults due to more immature temperature regulation. Diseases that cause fever in children do not necessarily do so in adults. Small children can easily get a fever of 39 °C, even with normal viral infections. Therefore, general condition is a more important measure of illness than temperature in this group. In young children, fever is often followed by vomiting and diarrhoea. Read more about children and fever here.

When should you contact a doctor if you have a fever?

• In case of febrile convulsions

• In case of fever above 40 °C

• In case of fever for more than 3-5 days

• Lethargy and apathy in children

• If you suspect meningitis. Typical symptoms are neck stiffness, rashes/bleeding on the skin that does not go away when you press on them, reduced consciousness/lethargy, frostbite and vomiting

• In case of other signs of illness and a very weakened general condition in addition to fever

• If you do not take in liquid

• For fever in children under three months

Sources: Norwegian health informatics for healthcare personnel, Store norske lexikon, Norwegian electronic medical handbook, Forskning.no, Norwegian medical handbook, Legevakthandbook.