Background: Previous limited data suggest that acute otitis media (AOM) caused by Streptococcus pneumoniae can present as a more severe disease than that caused by Haemophilus influenzae or Moraxella catarrhalis, as expressed by both tympanic membrane and systemic findings.
Objectives: To evaluate the severity of disease and impact of various pathogens, age, disease history and previous antibiotic therapy in children with AOM by using a comprehensive clinical/otologic score.
Patients and methods: The study group consisted of 372 children ages 3 to 36 months with AOM seen at the pediatric emergency room during 1996 through 2001. All patients had tympanocentesis and middle ear fluid culture performed at enrollment. Clinical status was determined by a clinical/otologic score evaluating severity (0 = absent to 3 = severe) of tympanic membrane findings (redness and bulging) and patient's fever, irritability and ear tugging. Maximal severity score was 15.
Results: There were 138 (37%) H. influenzae, 76 (21%) S. pneumoniae, 64 (17%) mixed infections (H. influenzae + S. pneumoniae) and 94 (25%) culture-negative cases. The overall clinical/otologic score was higher in culture-positive than in culture-negative patients (9.27 +/- 2.75 vs.8.38 +/- 3.08, P = 0.01). When analyzed by age groups, this difference was significant only for the youngest age group (3 to 6 months, P = 0.05). The severity scores for AOM caused by H. influenzae and S. pneumoniae were significantly higher than in the culture-negative AOM when tympanic membrane redness and bulging were analyzed separately. No differences were recorded in clinical/otologic scores between different pathogens (9.49 +/- 2.86, 9.03 +/- 2.72 and 9.09 +/- 2.54 for H. influenzae, S. pneumoniae and H. influenzae + S. pneumoniae, respectively). The mean clinical/otologic score was higher in culture-positive than in culture-negative patients without relationship to previous antibiotic treatment or number of previous AOM episodes.
Conclusions: (1) The clinical/otologic score of culture-positive young infants was higher than that of culture-negative infants; (2) the severity of tympanic membrane redness and bulging were the most indicative factors discriminating between a bacterial and nonbacterial etiology of AOM; and (3) the use of a clinical/otologic score could not discriminate among various bacterial etiologies of AOM.