Characteristics, management and outcome of a large necrotising otitis externa case series: need for standardised case definition

Epidemiology and risk factors for extension of necrotizing otitis externa

PURPOSE

Necrotizing otitis externa (OEN) is an aggressive and morbid infection of the external acoustic meatus. What are the risk factors for OEN extension?

METHODS

French monocentric retrospective study (2004-2021), including patients with OEN defined by the association of an inflamed EAM, a positive nuclear imaging, the presence of a bacteriological sample and the failure of a well-followed local and/or general antibiotic treatment. OEN was extensive if it was associated with vascular or neurological deficits, if nuclear imaging fixation and/or bone lysis extended beyond the tympanic bone.

RESULTS

Our population (n = 39) was male (74%), type 2 diabetic (72%), aged 75.2 years and pseudomonas aeruginosa was found in 88% of cases. Complications for 43% of patients were extensive fixation on nuclear imaging, for 21% of them the presence of extensive bone lysis, for 13% the appearance of facial palsy, for 5.3% the presence hypoglossal nerve palsy and for 2.5% the presence of thrombophlebitis or other nerves palsies. 59% of our population had extensive OEN. The diagnosis of the extensive OEN was made 22 days later (p = 0.04). The clinical presentation was falsely reassuring due to easier identification of the tympanic membrane (70% vs 46%, p = 0.17) but associated with periauricular oedema (42% vs 0%), bone exposure (16% vs 0%) and a temporomandibular joint pain (41% vs 12%).

CONCLUSION

Delayed treatment of OEN, identification of clinical bone lysis, especially when the tympanic membrane is easily visualized, and the presence of unbalanced diabetes are potential risk factors for extension of OEN.

A systematic review of antimicrobial treatment regimens and their outcomes in necrotising otitis externa

BACKGROUND

Necrotising otitis externa is a serious infection with minimal evidence underpinning its management. This review aims to synthesise published evidence of antimicrobial therapies and their outcomes in necrotising otitis externa.

METHODS

The review was PROSPERO registered (CRD42022353244) and conducted according to Preferred Reporting Items for Systematic Review and Meta-Analyses ('PRISMA') guidelines. A robust search strategy filtered 28 manuscripts into the final review. Antimicrobial therapy and clinical outcome data were extracted and analysed.

RESULTS

Published studies are heterogeneous, with high risk of bias and low certainty. Reporting of outcomes is poor and extremely variable. First-line therapy is most commonly in-patient (95 per cent) empiric fluoroquinolone (68 per cent) delivered intravenously (82 per cent). The lack of granular data and poor outcome reporting mean it is impossible to correlate treatment strategies with clinical outcomes.

CONCLUSION

Robust, consistent outcome reporting with reference to treatments administered is mandatory, to inform clinical management and optimise future research. Optimal antimicrobial choices and treatment strategies require clarification through prospective clinical trials.

[Research progress of necrotizing otitis externa]

Necrotizing otitis externa is a progressive infectious disease involving the external auditory canal and even the skull base, which can lead to serious complications and even death if not treated in time. In this paper, the latest advances in etiology, pathogenesis, clinical manifestations, diagnosis and treatment were reviewed based on previous literature, providing reference for clinical diagnosis, treatment and future research.