Malignant otitis externa: an Asian perspective on treatment outcomes and prognostic factors

Abstract

Objective: Malignant otitis externa (MOE) is a severe disease with varying outcomes. Despite advances in antibiotic treatment, a significant proportion still succumbs to this disease. We aimed to analyze the effect of clinical factors on prognosis and to review treatment outcomes in our institution.

Study design: Case series with retrospective chart review of MOE cases from 2006 to 2011.

Setting: Department of Otolaryngology-Head and Neck Surgery, National University Hospital, Singapore, a tertiary referral center.

Subjects and methods: Patients with MOE admitted for treatment were studied and divided into 2 outcome groups depending on response to a 6-week course of intravenous antibiotics. Demographic and disease factors were analyzed with regard to outcome.

Results: Nineteen cases were analyzed. Disease resolved in 63.2% after 6 weeks of antibiotics. Mortality was 21.1%. Age, diabetic control, duration of diagnostic delay, cranial nerve involvement, and inflammatory markers were not found to predict prognosis. Erythrocyte sedimentation rate and C-reactive protein levels correlated with disease activity and can be used to monitor progress. Clival involvement was associated with persistent disease (P = .002). Only 63.2% of cases had positive cultures. Pseudomonas aeruginosa was the main organism, and 33.3% of isolates were multidrug resistant. Outcome was not different in cases where culture-directed therapy was employed vs those where empirical ceftazidime and fluoroquinolone were used (P = .650).

Conclusion: Malignant otitis externa remains an insidious disease with significant mortality. Involvement of the clivus portends a poorer prognosis. Combination therapy with intravenous ceftazidime and oral fluoroquinolone remains relevant despite concerns of culture-negative cases and multidrug-resistant Pseudomonas.

Keywords: malignant otitis externa; necrotizing otitis externa; skull base osteomyelitis.