A rise in body TEMPERATURE that frequently accompanies certain illnesses. It is caused by the release of fever-producing proteins (pyrogens) by MONOCYTES and MACROPHAGES in response to a variety of infectious, immunological and other stimuli. The LYMPHOCYTES play a part in fever production because they recognise the foreign material provoking the immune response (ANTIGEN) and release LYMPHOKINES which promote the production of pyrogen. This acts on the thermo-regulatory centre in the HYPOTHALAMUS and results in an increase in heat generation and a reduction in heat loss, so body temperature rises. The body's temperature will also rise if exposed for too long to a high ambient temperature. (See HEAT STROKE.)
The average temperature in health ranges from 36.9 to 37.5 °C (98.4 to 99.5 °F). It varies with eating, exercise, the menstrual cycle, and the temperature of the surrounding atmosphere.
The average temperature of the body in health ranges from 36·9 to 37·5 °C (98·4 to 99·5 °F). It varies with eating, exercise, the menstrual cycle, and the temperature of the surrounding atmosphere. Fever is measured by how high the temperature rises above normal. At 41.1 °C (106 °F) the patient is in a dangerous state of hyperpyrexia (abnormally high temperature). If this persists for very long, the patient usually dies.
The body's temperature will also rise if exposed for too long to a high ambient temperature. (See HEAT STROKE.)
The onset of a fever, especially if sudden may be marked by a RIGOR, or shivering. The skin feels hot and dry and the pulse and breathing rates increase. The person is likely to be thirsty but will not want to eat; they may pass little but concentrated urine. Fever often causes a headache and sometimes nausea, and young children may experience a convulsion (see FEBRILE CONVULSIONS).
Fever is a physical sign rather than a disease in itself so the logical treatment is that of the underlying condition. It may make the person more comfortable to reduce the temperature by more direct methods: physical cooling by, for example, tepid sponging, and also the use of antipyretic drugs such as aspirin (adults) or paracetamol (adults and children).