A part of the brain called the hypothalamus acts as the body’s thermostat. When all is well in the body, the hypothalamus is set at the normal body temperature. Fever develops when the hypothalamus is set to a higher-than-normal temperature. This resetting of the hypothalamus is usually caused by small molecules called pyrogens in the blood.
Pyrogens can come from outside the body (external) or can be produced inside the body (internal). External pyrogens include toxins (poisons) produced by infectious viruses or bacteria. Internal pyrogens include abnormal chemicals that are produced by tumors and proteins that are released during the normal response of the immune system.
A fever is defined as a temperature 1 or more above the normal 98.6. Mild or short-term elevations are common with minor infections. High fevers, with temperatures of 103 and above, can signal a potentially dangerous infection.
There are several medications that can reduce body temperature by blocking the mechanisms that cause a fever. These so-called antipyretic agents include acetaminophen, ibuprofen and aspirin. All three of these drugs appear to be equally effective at reducing...