New directions in antiinfective therapy for community-acquired pneumonia in the emergency department.

The emergency department is becoming an increasingly important setting for the management of community-acquired pneumonia (CAP). This trend reflects the shortened hospital stays and decreased mortality among elderly hospitalized patients resulting from rapid administration of antimicrobials. In addition, decisions about the site of care (inpatient vs outpatient) and antimicrobial therapy frequently are made in the emergency department. Recent research and subsequent clinical guidelines may help with these decisions. For example, recently issued guidelines, such as those of the Infectious Diseases Society of America and the American Thoracic Society, suggest that selection of antimicrobials for CAP (which is typically empiric) should be based on the potential pathogens and likelihood of antimicrobial resistance. Macrolides and tetracyclines are recommended in younger patients with mild-to-moderate disease. Patients with more severe disease and those at risk for drug-resistant pathogens should be treated with broad-spectrum therapy, such as a newer fluoroquinolone or a cephalosporin plus a macrolide. When hospitalization is required, early switch from intravenous to oral therapy, followed by early discharge, can be a highly successful strategy. Antimicrobials that are available in both intravenous and oral formulations, such as the newer fluoroquinolones (e.g., levofloxacin and gatifloxacin), can simplify switch therapy For outpatients, an initial long-acting parenteral dose of azithromycin, ceftriaxone, or levofloxacin followed by oral therapy is an effective protocol. In addition, use of a prediction rule to identify low-risk patients with CAP may help guide decisions about the need for hospital admission.