Keywords: necrotising otitis externa, malignant otitis externa,
antibiotic, complications
Introduction – Necrotising otitis externa (NOE) is a serious,
progressive infection of the external ear canal. If untreated, it can
invade into temporal bone, skull-base and surrounding tissue resulting
in cranial nerve palsies, neurological infections and death. Patients
present with unremitting, severe otalgia, otorrhoea and oedematous ear
canals containing granulation. Surgery has a limited role; the mainstay
of treatment involves a long course of intravenous antibiotics.
Currently, there is no data on the complications of antibiotic treatment
for NOE. This project aims to provide evidence on the nature/frequency
of severe treatment-related complications requiring a change in
antibiotic regime.
Methods – A retrospective 5-year cohort analysis was performed
on 64 patients who were treated for confirmed NOE with intravenous
antibiotic therapy. Clinical notes, blood results and antibiotic
prescriptions were documented and analysed.
Results – Average duration of treatment was 11 weeks (range=38
weeks). There was an average of 2.1 antibiotic regimes per patient with
10 cases requiring inpatient admission due to treatment-related
complications. 63% of treatment changes were directly related to
adverse effects of intravenous antibiotics. Drug allergy/intolerance
(n=18) and clinical deterioration i.e. Lack of symptomatic improvement
and/or worsening inflammatory markers (n=18), were the most common
reasons for antibiotic change. Neutropenia, deranged liver function
tests and acute kidney injury were also recognised adverse effects of
treatment.
Conclusion – This study provides the first evidence on the
notable frequency of antibiotic-related complications in NOE patients.
Larger, multicentre studies are required in the future to validate our
findings and will better inform both clinicians and patients of the
risks of treatment.