Commentary on the 1993 American Thoracic Society guidelines for the treatment of community-acquired pneumonia

Early treatment of community-acquired pneumonia (CAP) is associated with im proved outcome. Since extensive diagnostic testing identifies an etiologic agent in only half of the cases and usually requires several hours or even days for results, CAP is most often initially treated empirically, In 1993, the American Thoracic Society (ATS) established guidelines to assist prima ry care physicians in antibiotic selection for the initial empiric treatmen t of CAP in immunocompetent adults. Since publication of the guidelines, th e incidence of certain bacteria has been redefined, antimicrobial resistanc e patterns have changed, risk factors for stratifying need for hospitalizat ion have been further defined, and newer antibiotics have been introduced, These changes necessitate a reevaluation of the 1993 ATS guidelines. This a rticle proposes a modification of the ATS guidelines. This modification con tinues to classify patients into groups, based on specific risk factors, to which a limited number of likely pathogens are identified and for which an tibiotic treatment regimens are developed. The modification differs from th e original ATS guidelines because of the changes in risk factors, Patient g roups are still broadly divided into outpatient and inpatient care, but ear lier risk factors of age and coexisting illness have been refined. Risk fac tors suggested herein as considerations to guide treatment include the pres ence of cardiopulmonary disease, history of smoking, severity of illness, r isk of drug-resistant Streptococcus pneumoniae and Pseudomonas aeruginosa, and need for ICU admission.