Diagnosis and Management of Group A Streptococcal Pharyngitis: A Practice Guideline

Alan L. Bisno 0 1 2 Chairman 0 1 2 Michael A. Gerber 0 1 2 Jack M. Gwaltney 0 1 2 Jr. 0 1 2 Edward L. Kaplan 0 1 2 Richard H. Schwartz 0 1 2 Executive Summary 0 1 2 0 Clinical Infectious Diseases 1997;25:574-83 q 1997 by The University of Chicago. All rights reserved. 1058-4838/97/2503-0002$03.00 1 This guideline is part of a series of updated and new guidelines from the IDSA that will appear in CID. Miami Veterans Affairs Medical Center , 1201 N.W. 16th Street, Miami, Florida 33125 2 From the Acute Pharyngitis Guideline Panel, Infectious Diseases Society of America , Alexandria, Virginia This is the second in a series of practice guidelines commissioned by the Infectious Diseases Society of America through its Practice Guidelines Committee. The purpose of these guidelines is to provide assistance to clinicians when making decisions on treating the conditions specified in each guideline. The targeted providers are pediatricians, family practitioners, and internists. The targeted patients and setting for the acute pharyngitis guideline are pediatric, adolescent, and adult outpatients with a complaint of sore throat. Funding was provided by the IDSA. Panel members represented experts in adult and pediatric infectious diseases. The guidelines are evidence-based. A standard ranking system was used for the strength of the recommendations and the quality of the evidence cited in the literature reviewed. The document has been subjected to external review by peer reviewers as well as by the Practice Guidelines Committee and was approved by the IDSA Council. An executive summary, algorithms, and tables highlight the major recommendations. Indicators of quality will assist in guideline implementation. The guideline will be listed on the IDSA home page at http://www.idsociety.org. Diagnosis Acute pharyngitis is one of the most frequent illnesses for which pediatricians and other primary care physicians are consulted. Although the group A streptococcus is the most common bacterial cause of acute pharyngitis, only a minority of patients with pharyngitis are infected by group A streptococci. Moreover, group A streptococcal pharyngitis is the only commonly occurring form of acute pharyngitis for which antibiotic therapy is definitely indicated. Therefore, when a physician treats a patient with acute pharyngitis, the clinical decision that usually needs to be made is whether the pharyngitis is attributable to group A streptococci. Therapy Patients with acute streptococcal pharyngitis should receive therapy with an antimicrobial agent in a dosage and for a duration that is likely to eradicate the infecting organism from the pharynx. A number of antibiotics have been shown to be effective in therapy for group A streptococcal pharyngitis. These agents include penicillin and its congeners (such as ampicillin, amoxicillin, and the semisynthetic penicillins) as well as numerous cephalosporins, macrolides, and clindamycin. However, penicillin remains the treatment of choice because of its proven efficacy, safety, narrow spectrum, and low cost. Intramuscular benzathine penicillin G is preferred for patients who are unlikely to complete a full 10-day course of oral therapy. Erythromycin is a suitable alternative for patients who are allergic to penicillin. First- or second-generation cephalosporins are also acceptable for treating patients who do not exhibit immediate hypersensitivity to b-lactam antibiotics. Most oral antibiotics must be administered in the conventional 10-day course to achieve maximal pharyngeal eradication of group A streptococci, but the use of certain newer agents has been reported to achieve comparable bacteriologic and clinical cure rates among patients with streptococcal pharyngitis when these agents are given for 5 days. However, definitive results from comprehensive studies are not available; thus, final evaluation of these proposed shorter courses of oral antibiotic therapy is not possible, and they cannot be recommended at this time. Moreover, these antibiotics have much broader spectrums than penicillin, and most, even when administered for short courses, are more expensive. Except under special circumstances, neither repeated bacteriologic testing (culture or RADT) of patients who have successfully completed a course of antimicrobial therapy nor routine testing of asymptomatic household contacts of patients with group A streptococcal pharyngitis is recommended. A small percentage of patients will have recurrences of acute pharyngitis that are associated with throat cultures (or RADTs) positive for group A streptococci within a short period following completion of a course of antimicrobial therapy. Such episodes may be treated with one of the antimicrobial agents appropriate for treatment of the initial illness. If these episodes were previously treated with oral agents and compliance is in question, retreatment with intramuscular benzathine penicillin G should be considered. When multiple episodes occur over the course of months or years, it may be difficult to differentiate viral infections in a streptococcal carrier from true group A streptococcal infections. Certain antimicrobial agents, such as clindamycin and amoxicillin/clavulanate, may be beneficial because they have been shown to yield high rates of pharyngeal eradication of streptococci under these particular circumstances. Objective Options Group A streptococcal pharyngitis (pharyngotonsillitis) is an acute infection of the oropharynx and/or nasopharynx with Streptococcus pyogenes. The objective of this practice guideline is to provide recommendations for the accurate diagnosis and optimal treatment of group A streptococcal pharyngitis. Physicians caring for patients with acute pharyngitis must formulate differential diagnoses and determine which, if any, confirmatory tests should be performed. If clinical and laboratory evaluations result in a diagnosis of group A b-hemolytic streptococcal pharyngitis, one of several antimicrobial agents and treatment schedules may be selected. The desired outcomes are: (1) prevention of acute rheumatic fever; (2) prevention of suppurative complications (e.g., peritonsillar abscess, cervical lymphadenitis, or mastoiditis); (3) abatement of clinical symptoms and signs; (4) a rapid decrease in infectivity so as to reduce transmission of group A b-hemolytic streptococci to family members, classmates, and other close contacts and to allow the rapid resumption of usual activities; (5) minimization of potential adverse effects of inappropriate antimicrobial therapy. Evidence We reviewed a large number of clinical trials of diagnostic and treatment strategies for group A streptococcal pharyngitis. The reports were examined for indicators of quality. For example, studies of treatment were evaluated for randomization, blinding, use of streptococcal typing to differentiate treatment failures from new infections, duration and timing of follow-up examinations, and (...truncated)