#x203A; Although infection is the most common cause of fever, fever is also a common finding in hypersensitivity reaction, autoimmune diseases, and malignancy.
› Febrile response is mediated by endogenous pyrogens (cytokines) in response to invading exogenous pyrogens, primarily microorganisms or their direct products (toxins).
› These endogenous pyrogens act on thermosensitive neurons in the hypothalamus, which ultimately upgrade the set point via prostaglandins.
› The body reacts by increasing the heat production and decreasing the heat loss until the body temperature reaches this elevated set point.
› Fever, in contrast to hyperthermia, will not climb up relentlessly because of an effective central control of the hypothalamic center.
› Cytokines play a pivotal role in the immune response by activation of the B cells and T lymphocytes. The production of fever simultaneously with lymphocyte activation constitutes the clearest and strongest evidence in favor of the protective role of fever.
› The protective processes of the immune response are optimal at high temperature (around 39.5°C).
› Not all effects resulting from fever generation benefit the host; some are harmful and even lethal. This occurs mainly by overproduction of the cytokines or imbalance between cytokines and their inhibitors, such as severe and fulminate infections and septic shock.
KeywordsKawasaki Disease Heat Production Chronic Granulomatous Disease Skin Blood Flow Toxic Shock Syndrome