HSC Section 8_April 2017

Reprinted by permission of Otolaryngol Head Neck Surg. 2013; 148(6):991-996.

Original Research—International Health

Otolaryngology– Head and Neck Surgery 148(6) 991–996 American Academy of Otolaryngology—Head and Neck

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

Surgery Foundation 2013 Reprints and permission:

sagepub.com/journalsPermissions.nav DOI: 10.1177/0194599813482107 http://otojournal.org

Shaun Loh, MBBS, MRCS 1 , and Woei Shyang Loh, MBBS, FRCS 1

Received October 12, 2012; revised February 15, 2013; accepted February 20, 2013. M alignant otitis externa (MOE) is a severe infection that typically affects the elderly, patients with diabetes, and immunocompromised patients. 1 Pseudomonas aeruginosa is the main causative organism. 2 Infection begins in the external auditory canal (EAC), spreading through the fissures of Santorini to surrounding structures. 3 Advances in anti-pseudomonal antibiotics have reduced mortality, which was 50% when MOE was first described. 1 The clinical course is varied and outcome pre- diction is difficult. Studies have attempted to identify prog- nostic factors to guide treatment, but a lack of consensus exists. This series aims to review our experience and to identify prognostic factors that might influence outcome. Methods The study was approved by the Ethics Committee at the National University Hospital, Singapore. The database of the Department of Otolaryngology–Head and Neck Surgery was searched for cases of MOE treated at our tertiary center between 2006 and 2011. All patients with MOE were admitted for intravenous antibiotics. The regimen used consisted of intravenous cefta- zidime and oral fluoroquinolone. Oral fluoroquinolone was omitted only in patients who had already been pretreated with long courses of this without improvement. Isolated cases where cultures showed organisms resistant to ceftazi- dime were given culture-specific antibiotics. Patients who improved were discharged with outpatient antibiotic ther- apy. Those who did not improve continued inpatient treat- ment. Disease was deemed to have resolved in patients who were symptom free for more than 2 weeks with

No sponsorships or competing interests have been disclosed for this article.

Abstract Objective . Malignant otitis externa (MOE) is a severe disease with varying outcomes. Despite advances in antibiotic treat- ment, a significant proportion still succumbs to this disease. We aimed to analyze the effect of clinical factors on prog- nosis 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 treat- ment were studied and divided into 2 outcome groups depend- ing 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 invol- vement, and inflammatory markers were not found to predict prognosis. Erythrocyte sedimentation rate and C-reactive pro- tein 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 ceftazi- dime and fluoroquinolone were used ( P = .650). Conclusion . Malignant otitis externa remains an insidious dis- ease with significant mortality. Involvement of the clivus por- tends a poorer prognosis. Combination therapy with intravenous ceftazidime and oral fluoroquinolone remains rele- vant despite concerns of culture-negative cases and multidrug- resistant Pseudomonas . Keywords malignant otitis externa, necrotizing otitis externa, skull base osteomyelitis

1 Otolaryngology–Head and Neck Surgery (ENT), National University Hospital, Singapore

Corresponding Author: Shaun Loh, MBBS, MRCS, Otolaryngology–Head and Neck Surgery (ENT), National University Hospital, Singapore. Email: shaunloh7@gmail.com

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