January 26, 2022
Fever or pyrexia is an increase in body temperature above the normal limit in response to illness or organic disturbance. There is no universal value for what is considered the upper limit of normal temperature. The values indicated in the medical literature vary between 37.5 ºC and 38.3 ºC. The temperature rise is caused by a rise in the thermal setpoint. This value is controlled by the body's thermoregulatory center in the hypothalamus. This causes the body to produce more heat and strive to conserve that heat, causing muscle contractions and feeling cold. When the temperature set point returns to normal, the person feels hot, the skin becomes red and starts to sweat. In rare cases, a fever can cause febrile seizures, which are more common among younger children. Generally, fevers do not raise the body temperature beyond 41 or 42°C. Fever can be caused by numerous medical conditions, from mild conditions to life-threatening conditions. Among these conditions are viral, bacterial or parasitic infections such as constipation, urinary tract infections, meningitis or malaria. Non-infectious causes include vasculitis, deep vein thrombosis, adverse drug effects, and cancer. It is a distinct condition from hyperthermia, which is an increase in body temperature above the thermal set point temperature, caused by excessive heat production or lack of heat loss. Treatment is usually not necessary to bring the fever down. However, treating the associated pain and inflammation can help a person rest. Medications such as ibuprofen or paracetamol and measures to lower the temperature are usually recommended. Measures such as placing a cold damp cloth on the forehead or taking a hot bath are not effective and can only cause discomfort to the person. Babies younger than three months, people with serious health conditions such as immunosuppression, or people with symptoms other than fever may need medical attention. Hyperthermia requires treatment. Fever is one of the most common medical signs. About 30% of medical consultations for children are related to fever. About 75% of seriously ill adults have a fever. Although fever is a useful defense mechanism, treating fever does not appear to worsen the prognosis of other conditions. Both parents and health professionals tend to overestimate fever.