Clinical outcomes of otogenic skull base osteomyelitis

Skull base infections, their complications, and management

OBJECTIVE

Our review aims to summarize the current literature on skull base infections (SBIs) and retrospectively analyze any such cases encountered at our institution.

DESIGN

A literature search was conducted using online databases PubMed, MEDLINE, and ResearchGate with the terms "skull base osteomyelitis," "temporal bone osteomyelitis," "skull base infections," "necrotizing otitis media," and "SBO". References from the resulting manuscripts were reviewed for relevant articles. A search of our electronic health records using the same key terms was also performed to identify patients with a tissue biopsy-confirmed diagnosis of skull base infections. Patients with an indeterminate diagnosis or inaccessible/poor imaging were excluded.

SETTING

A level one trauma and major tertiary academic medical center.

PARTICIPANTS

All patients treated at the University of California Davis Health System with a confirmed diagnosis of skull base infections from January 2005 to November 2020.

MAIN OUTCOME MEASURES

Imaging results, symptoms, treatment, morbidity, and mortality.

RESULTS

Our literature search yielded 59 articles ranging from 1982 to 2021. A retrospective search of our electronic health records identified two cases of skull base infections.

CONCLUSION

Skull base infections have no pathognomonic findings. A multimodal approach with computed tomography (CT), magnetic resonance imaging (MRI), and nuclear medicine is necessary to characterize the disease process in addition to a biopsy for definitive diagnosis. Other diagnoses can mimic SBI on imaging, such as nasopharyngeal carcinoma and inflammatory pseudotumor. Culture-guided antimicrobial treatment and surgery are mainstay therapies. Other adjuvant strategies currently lack the robust evidence necessary to characterize their risks and benefits.

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.

Clinico-Radiological Evaluation for Longitudinal Assessment in Central Skull Base Osteomyelitis: Proposal of Novel Scoring System

This study aims to evaluate clinical, radiological and laboratory parameters for longitudinal assessment and prognostication in central skull base osteomyelitis (CSBO). Novel radiological score and cranial nerve assessment score (CNAS) have been proposed and analysed along with pain score (VAS), ESR, CRP, WBC count, and HbA1c for utility in disease-monitoring and predicting outcome in CSBO. CSBO cases managed in a tertiary care centre from January 2018 to November 2020, with a minimum follow-up of 6 months were included. The parameters were recorded at presentation, 3-month, 6-month postoperative follow-up, and at completion of therapy, for statistical analysis. Significant positive correlation was found amongst pain score, CNAS, radiological score, ESR, and CRP at different timelines. On longitudinal assessment, there was a statistically significant reduction in above-mentioned parameters, in the cases who recovered. Those with initial radiological score < 30, pain score ≤ 7, and CNAS < 10 showed early clinical improvement, required shorter duration of antimicrobial therapy, and exhibited higher probability of becoming disease-free at an earlier time, compared to those presenting with higher scores. We propose the use of pain score, a novel cranial nerve assessment score, and a novel radiological score for longitudinal assessment in CSBO. The trend in these parameters along with ESR and CRP are useful to monitor the disease process. The initial assessment scores can predict duration of antimicrobial therapy and probability of early recovery. WBC count and HbA1c were neither useful for disease-monitoring nor predicting outcome.

Systematic review of the diagnosis and management of necrotising otitis externa: Highlighting the need for high-quality research

OBJECTIVES

To present a systematic review and critical analysis of clinical studies for necrotising otitis externa (NOE), with the aim of informing best practice for diagnosis and management.

DESIGN

Medline, Embase, Cochrane Library and Web of Science were searched from database inception until 30 April 2021 for all clinical articles on NOE. The review was registered on PROSPERO (ID: CRD42020128957) and conducted in accordance with PRISMA guidelines.

RESULTS

Seventy articles, including 2274 patients were included in the final synthesis. Seventy-three percent were retrospective case series; the remainder were of low methodological quality. Case definitions varied widely. Median patient age was 69.2 years; 68% were male, 84% had diabetes and 10% had no reported immunosuppressive risk factor. Otalgia was almost universal (96%), with granulation (69%) and oedema (76%) the commonest signs reported. Pseudomonas aeruginosa was isolated in 62%, but a range of bacterial and fungal pathogens were reported and 14% grew no organism. Optimal imaging modality for diagnosis or follow-up was unclear. Median antimicrobial therapy duration was 7.2 weeks, with no definitive evidence for optimal regimens. Twenty-one percent had surgery with widely variable timing, indication, or procedure. One-year disease-specific mortality was 2%; treatment failure and relapse rates were 22% and 7%, respectively.

CONCLUSION

There is a lack of robust, high-quality data to support best practice for diagnosis and management for this neglected condition. A minimum set of reporting requirements is proposed for future studies. A consensus case definition is urgently needed to facilitate high-quality research.

Otogenic Central Skull Base Osteomyelitis With Retropharyngeal Extension: A Case Report

Skull base osteomyelitis (SBO) is a life-threatening condition in patients with underlying comorbidities. Ear infections may spread through normal skull base fissures in this group of patients. However, its diagnosis is frequently delayed due to the unspecific clinical findings at onset, such as headache, with diverse cranial neuropathies later as the disease progresses. We present the case of a patient with otogenic skull base osteomyelitis complicated with retropharyngeal extension, treated with surgical drainage and broad-spectrum antibiotics directed toward extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli, with recurrence of the infection three months later. With this case study, we aim to stress the importance of antimicrobial resistance and how it can preclude an otherwise favorable prognosis.