[Fever with chills].

Abrupt onset of fever with chills represents a body response to various stimuli called exogenous pyrogens. These substances interact with monocytes and macrophages, thus releasing various cytokines including interleukin-1 and tumor necrosis factor (endogenous pyrogens). Endogenous pyrogens act centrally on the thermosensitive neurons in the hypothalamus to increase the core body temperature by increasing heat production and decreasing heat loss. In addition, endogenous pyrogens trigger a non-specific inflammatory response and amplify the specific immune response through activating the T- and B-cell system. Pyogenic infections are the most frequent and most important cause of abrupt onset of fever with chill, but a similar pattern of fever may occur in many other situations. In many instances, a thorough history and a complete physical examination will produce a presumptive diagnosis. Further management decisions depend on the clinical conditions and on the localization of the infection. Patients with compromised vital functions, with involvement of the central nervous system, with chills associated with prolonged fever without localizing symptoms or physical findings, or with symptoms of intraabdominal sepsis, must be promptly hospitalized. The most important aspects of treatment should be directed at the cause of fever, and antipyretic drugs should be used after evaluation of relative risks in the individual case.