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Fever, also known as pyrexia and febrile response, is defined as having a temperature above the normal range due to an increase in the body's temperature set-point. There is not a single agreed upon upper limit for normal temperature with sources using values between . The increase in set-point triggers increased muscle contraction and causes a feeling of cold.〔 This results in greater heat production and efforts to conserve heat.〔 When the set-point temperature returns to normal a person feels hot, becomes flushed, and may begin to sweat. Rarely a fever may trigger a febrile seizure. This is more common in young children.〔 Fevers do not typically go higher than .〔 A fever can be caused by many medical conditions ranging from the not serious to potentially serious. This includes viral, bacterial and parasitic infections such as the common cold, urinary tract infections, meningitis, malaria and appendicitis among others. Non-infectious causes include vasculitis, deep vein thrombosis, side effects of medication, and cancer among others. It differs from hyperthermia, in that hyperthermia is an increase in body temperature over the temperature set-point, due to either too much heat production or not enough heat loss.〔 Treatment to reduce fever is not required.〔 Treatment, however, may increase comfort and help a person rest. Measures such as putting a cool damp cloth on the forehead and having a slightly warm bath may help.〔(【引用サイトリンク】url=http://www.cdc.gov/flu/homecare/treatfever.htm )〕 Medications such as ibuprofen or paracetamol may also be effective at lowering the temperature. Children younger than three months, people with serious medical problems such as a compromised immune system, and people with other symptoms may require medical attention. Hyperthermia does require treatment.〔 Fever is one of the most common medical signs. It is part of about 30% of healthcare visits by children and occurs in up to 75% of adults who are seriously sick. While fever is a useful defense mechanism, treating fever does not appear to worsen outcomes. Fever is viewed with greater concern by parents and healthcare professionals than it usually deserves, a phenomenon known as fever phobia.〔 ==Definition== A wide range for normal temperatures has been found. Central temperatures, such as rectal temperatures, are more accurate than peripheral temperatures. Fever is generally agreed to be present if the elevated temperature is caused by a raised set point and: * Temperature in the anus (rectum/rectal) is at or over 〔〔 * Temperature in the mouth (oral) is at or over * Temperature under the arm (axillary) or in the ear (otic) is at or over In healthy adult men and women, the range of normal, healthy temperatures for oral temperature is , for rectal it is , for tympanic membrane (the ear drum) it is , and for axillary (the armpit) it is . Harrison's textbook of internal medicine defines a fever as a morning oral temperature of >37.2 °C (>98.9 °F) or an afternoon oral temperature of >37.7 °C (>99.9 °F) while the normal daily temperature variation is typically 0.5 °C (0.9 °F). Normal body temperatures vary depending on many factors, including age, sex, time of day, ambient temperature, activity level, and more. A raised temperature is not always a fever. For example, the temperature of a healthy person rises when he or she exercises, but this is not considered a fever, as the set-point is normal. On the other hand, a "normal" temperature may be a fever, if it is unusually high for that person. For example, medically frail elderly people have a decreased ability to generate body heat, so a "normal" temperature of may represent a clinically significant fever. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Fever」の詳細全文を読む スポンサード リンク
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