Elevation above normal of body temperature. Normal body temperature oois 37C in the mouth and 0.6C lower in the axilla (armpit). A fever may be accompanied by symptoms such as shivering, headache, sweating, thirst, faster-thannormal breathing, and a flushed face. Confusion or delirium sometimes occur, especially in the elderly; a high fever may cause seizures in a child under 5 years (see convulsion, febrile) or coma. Most fevers are caused by a bacterial infection such as tonsillitis or a viral infection such as influenza. In these cases, proteins called pyrogens are released when the white blood cells fight the microorganisms that are responsible for the infection. Pyrogens act on the temperature controlling centre in the brain, causing it to raise the body temperature in an attempt to destroy the invading microorganisms. Fever may also occur in conditions, such as dehydration, thyrotoxicosis, lymphoma, and myocardial infarction, where infection is not present. Drugs such as aspirin or other nonsteroidal anti-inflammatory drugs, or paracetamol may be given to reduce fevers that are due to infections. Otherwise, treatment is directed at the underlying cause (for example, giving antibiotic drugs for a bacterial infection).


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