Criteria, performance and diagnostic problems in diagnosing acute otitis media

We aimed to assess criteria when diagnosing acute otitis media and related performance in general practice in Denmark. Furthermore, we aimed to identify the scale of and the reasons for diagnostic uncertainty.

We conducted: (i) a survey among GPs assessing criteria; and (ii) prospective registration of acute otitis-media-related consultations performed by GPs assessing performance. The survey was sent to all 790 GPs in Funen, North Jutland and Ringkøbing counties, Denmark. A total of 568 (72%) of all GPs in the three counties responded. A total of 368 children with acute otitis media or previous acute otitis media visiting 151 GPs were studied. The main outcome measures were: (i) criteria for symptoms and findings suggesting the diagnosis acute otitis media, criteria for use of equipment and reasons for diagnostic uncertainty; and (ii) prevalence of symptoms and findings in diagnosed cases, equipment used and multivariate analysis of factors predicting diagnostic certainty.

The symptoms of earache, fever, reduced hearing, findings of bulging eardrum, red eardrum and purulent otorrhea were important criteria used during both diagnosis of acute otitis media by the GPs and assessment of performance. In the prospective study, diagnostic certainty of acute otitis media was 67% (95% CI 58-76) in children under 2 years and 75% (95% CI 69-81) in older children. Diagnostic certainty was statistically related (P < 0.05) to a good view of the eardrum and the findings of purulent otorrhea or a bulging eardrum. Logistic regression revealed that the two most important factors predicting diagnostic certainty were a satisfactory view of the eardrum, with an odds ratio (OR) 11.0 (95% CI 4.1-29.5), and purulent otorrhea OR 10.1 (95% CI 3.1-32.9). Main reasons for diagnostic uncertainty given by GPs were differential diagnostic doubts, insufficient view of the eardrum and lack of knowledge.

Danish GPs' criteria for the diagnosis of acute otitis media were stricter than criteria used internationally. The discrepancy between diagnostic criteria and performance was small. Diagnostic accuracy and certainty could be substantially improved by cleaning the ear canal when needed and by widespread use of pneumatic otoscopy.