Streptococcal tonsillopharyngitis : clinical vs. microbiological diagnosis

This study aimed to evaluate the role of clinical diagnosis vs. rapid antigen detection tests (RADT) in identifying streptococcal vs. non-streptococcal cases of acute pharyngitis (AP) with respect to a scoring schedule. The Breese scoring system, modified by eliminating the count of peripheral WBC, was used in the study. At enrolment, cases of AP observed by office-based pediatricians were judged on a clinical basis as possibly of streptococcal or of non-streptococcal origin and a clinical score recorded. At the end of the visit and following completion of the clinical score to document the presence/absence of a group A beta haemolytic streptococcus (GABHS), a confirmatory RADT was performed. In RADT negative cases a standard throat swab and culture were performed. In all, 629 children presenting with AP were enrolled in the study. A correct clinical diagnosis was predicted on the basis of the clinical observation in 74.2% of cases (with a sensitivity of 81.1% and specificity of 70.5%). In cases judged as "streptococcal", a mean score of 27.6 was recorded both in those patients with a positive or negative RADT/throat swab for GABHS. By contrast, among cases considered of non-streptococcal aetiology, negative RADT/culture had a mean score of 24.3 compared to a mean score of 25 in those with a positive RADT/culture. Intragroup score differences were not significant, while intergroup differences were highly significant. Optimization of AP treatment requires careful identification of streptococcal cases, avoiding unnecessary antibiotic treatment which would contribute to enhancing antibiotic resistance and increase medical treatment costs. We document that clinical observation alone, although performed by skilled pediatricians, will misdiagnose a sizeable percentage of cases. As indicated by this study, scores may suffer from a subjective interpretative bias in grading the severity of signs and symptoms