Diagnostic approach to patients at risk of otogenic skull base osteomyelitis

Abstract

Background

Otogenic skull base osteomyelitis (OSBO) is rare and potentially fatal sequelae of otitis externa. Accurate and timely diagnosis is important due to rising incidence, morbidity and costs associated with treatment. Consensus on the diagnostic approach for OSBO has yet to be reached, in particular the utility of imaging modalities.

Aims/objectives

This study reviews a single institution’s high-volume experience of OSBO, with the aim of analysing clinicopathologic features and imaging studies to develop a diagnostic algorithm.

Material and methods

A retrospective review of patients admitted with OSBO from 2009 to 2019, was performed. After applying inclusion and exclusion criteria, 103 patients with 106 unique episodes of suspected OSBO were selected. De-identified information including patient demographics, clinicopathologic features and imaging outcomes was recorded and analysed.

Results

HbA1c ≥ 7% significantly predicted for OSBO in univariate (OR 7.83, 95% CI 1.85–33.16, p = 0.01) and multivariate analyses (OR 5.21, 95% CI 1.05–25.81, p = 0.04). The CT/technetium-99m/gallium-67 combination produced better diagnostic accuracy for OSBO (AUROC 0.96, 95% CI 0.92–1), when compared to a CT/MRI combination (AUROC 0.86, 95% CI 0.79–0.93).

Conclusions and significance

Once there is a clinical suspicion for OSBO, diagnosis is established by synthesising results from clinical assessment, pathologic investigations and imaging modalities. The imaging utilised to diagnose OSBO should vary according to the clinical situation and limitations of each modality.

Chinese Abstract

背景：耳源性颅底骨髓炎 (OSBO) 是一种罕见且可能致命的外中耳炎后遗症。由于发病率和治疗成本不断上升, 准确和及时的诊断非常重要。OSBO 的诊断方法尚未达成共识, 尤其是关于成像方式的实用性。

目的：本研究回顾了一个医疗机构的大量 OSBO 病例, 分析临床病理学特征和影像学研究以开发诊断方法。

材料与方法：对2009年至2019年OSBO入院患者进行了回顾性分析。根据纳入和排除标准, 有 106 次疑是 OSBO的独特发作的103 名患者被选中。记录并分析了包括患者人口统计、临床病理学特征和成像结果在内的公共信息。

结果：单变量（OR 7.83, 95% CI 1.85–33.16, p = .01) 和多变量(OR 5.21, 95% CI 1.05–25.81, p = .04) 分析中, HbA1c 7% 明显预测OSBO。 CT/锝 -99m/镓 -67 组合对 OSBO的诊断准确性（AUROC 0.96, 95% CI 0.92–1）与 CT/MRI 组合相比 (AUROC 0.86, 95% CI 0.79–0.93)相比更好。

结论和意义：一旦临床怀疑 OSBO, 诊断依据是综合临床评估、病理学研究和影像方式的结果。根据临床情况和每种方式的局限性, 用于诊断 OSBO 的影像应有所不同。

Keywords:

• Skull base osteomyelitis
• malignant otitis externa
• necrotising otitis externa
• diagnosis
• otogenic

Acknowledgements

The authors acknowledge and thank the Infectious Disease Unit at St Vincent’s Hospital Melbourne for their assistance in the management of the patients in this study.

Disclosure statement

No potential conflict of interest was reported by the authors.