RT Book, Section A1 Jameson, J. Larry A1 Fauci, Anthony S. A1 Kasper, Dennis L. A1 Hauser, Stephen L. A1 Longo, Dan L. A1 Loscalzo, Joseph SR Print(0) ID 1167062918 T1 Fever, Hyperthermia, and Rash T2 Harrison's Manual of Medicine, 20e YR 2020 FD 2020 PB McGraw-Hill Education PP New York, NY SN 9781260455342 LK accessmedicine.mhmedical.com/content.aspx?aid=1167062918 RD 2024/03/28 AB Temperature: The hypothalamic thermoregulatory center balances excess heat production from metabolic activity in muscle and liver with heat dissipation from the skin and lungs to maintain a normal body temperature of 36.8° ± 0.4°C (98.2° ± 0.7°F), with diurnal variation (lower in A.M., higher in P.M.)Fever: An elevation of body temperature (>37.2°C/98.9°F in the morning and >37.7°C/99.9°F in the evening) in conjunction with an increase in the hypothalamic set pointFever of unknown origin(FUO): Temperatures >38.3°C (>101°F) on two or more occasions and an illness duration of ≥3 weeks, with no known immunocompromised state and unrevealing laboratory and radiologic investigations into the causeHyperpyrexia: Temperatures >41.5°C (>106.7°F) that can occur with severe infections but more commonly occur with CNS hemorrhagesHyperthermia: An uncontrolled increase in body temperature that exceeds the body’s ability to lose heat without a change in the hypothalamic set point. Hyperthermia does not involve pyrogenic molecules.Pyrogen: Any fever-causing substance, including exogenous pyrogens (e.g., microbial toxins, lipopolysaccharide, superantigens) and pyrogenic cytokines (e.g., IL-1, IL-6, TNF)