Respiratory infections in the 1990s.

Respiratory infections occur in a variety of settings, affecting patients who live in the community, those who are hospitalized, as well as residents of chronic care facilities. Management of pneumonia and bronchitis is continually changing as the nature of the infecting pathogens, the susceptibility of microbes to antibiotics, and the nature of the host at risk for infection are evolving. Advances in the understanding of disease pathogenesis have led to new approaches for therapy and prevention, using a variety of techniques ranging from immunization to the manipulation of cytokines. One inevitable consequence of this ever-changing field is that our incomplete foundation of knowledge leads to disagreements among experts about the most efficient approach to disease management. In this review, a number of these controversies are examined, with a particular emphasis on the diagnostic approach to pneumonia arising in both the community and the hospital. In addition, a number of pathogenetic and epidemiologic principles are examined, which may have bearing on the prevention of pneumonia in the elderly and the mechanically ventilated patient.