Malignant Otitis Externa: An Asian Perspective on Treatment Outcomes and Prognostic Factors

Abstract

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. Case series with retrospective chart review of MOE cases from 2006 to 2011. Department of Otolaryngology-Head and Neck Surgery, National University Hospital, Singapore, a tertiary referral center. 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. 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). 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.