AB174. SOH23ABS_011. Malignant otitis externa treatment adherence

Background: Malignant otitis externa (MOE) is a life-threatening infection mainly affecting the external auditory canal (EAC) and skull base. From the EAC, it can spread anteriorly, medially, intracranially, or posteriorly. MOE usually affects those with some degree of immunosuppression, such as type 2 diabetes mellitus (T2DM). Complications of MOE are severe and can present rapidly. These include sepsis, cranial nerve palsies, meningitis, brain abscesses, and osteomyelitis. It is pertinent that appropriate antimicrobials are utilised for a minimum of six weeks. Our research aimed to evaluate treatment adherence.

Methods: We compiled a database of all patients diagnosed with MOE in Lincoln County Hospital during an 18-month period. All patients had radiologically confirmed disease. We recorded the duration of treatment for these patients, taking into account both intravenous and oral antibiotics. Finally, we compared our results with the national recommendations provided by ENT UK guidelines.

Results: A total of 10 patients were included in our study. All were over 65 years, with the mean age being 78.2 years. Seven of the ten patients had a past medical history of T2DM. Of these 10 patients initially diagnosed with MOE, 3 patients had their diagnosis changed to diffuse otitis externa, and one died of coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) complications 4 days after admission. Of the remaining six patients, average antibiotic duration was 60.16 days. Two of these six patients were incorrectly prescribed first-line antibiotics.

Conclusions: MOE is associated with life-threatening complications. Therefore, early identification of MOE and treatment with the appropriate antimicrobials for the total duration of therapy is required.

Keywords: External auditory canal (EAC); malignant otitis externa (MOE); necrotising otitis externa; skull base; type 2 diabetes mellitus (T2DM)