HSC Section 8_April 2017

109 / 264

Original Research—International Health
Malignant Otitis Externa: An Asian
Perspective on Treatment Outcomes and
Prognostic Factors
Otolaryngology–
Head and Neck Surgery
148(6) 991–996
American Academy of
Otolaryngology—Head and Neck
Surgery Foundation 2013
Reprints and permission:
DOI: 10.1177/0194599813482107
Shaun Loh, MBBS, MRCS1, and Woei Shyang Loh, MBBS, FRCS 1
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
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
1Otolaryngology–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:
Reprinted by permission of Otolaryngol Head Neck Surg. 2013; 148(6):991-996.
88