Metabolic effects of infection.

The metabolic effects of infection influence a wide variety and number of host biochemical pathways and molecular mechanisms. These responses function in support of the many diverse defense systems used by the body to control or eliminate invading microorganisms. Despite their complexity and diversity, these responses develop in relatively consistent, almost stereotypic pattern of progression during the course of generalized febrile infections caused by many kinds of different agents. If an infection localizes within an organ system, derangements of function of that organ may be superimposed upon the generalized responses. These general metabolic responses are initiated and modulated by the release of endogenous mediators, hormones, and by central nervous system stimuli as well. The magnitude of these metabolic changes can be influenced by the severity and duration of the illness. Clinically, the most visible metabolic effects of an infectious disease are catabolic. They can be documented by measurable losses of body constituents and nutrients. However, it must be kept in mind that equally important anabolic processes are taking place at the same time. It is these latter anabolic events that are of importance in host defensive mechanisms.