A review of thirty-nine patients diagnosed with necrotising otitis externa over three years: Is CT imaging for diagnosis sufficient?

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.

Necrotizing Otitis Externa: A Proposal for Diagnostic and Therapeutic Approach

Introduction  Necrotizing otitis externa has a high impact on the quality of life of patients and has shown a significant increase in its incidence in recent years. There has been a change in the profile of affected patients and a lack of consensus on the management of these patients. Objective  To develop a practical and effective care protocol to standardize the diagnostic and therapeutic management of necrotizing otitis externa. Methods  A retrospective cohort study of necrotizing otitis externa patients between January 2015 and December 2020. Results  There were 34 patients with two bilateral cases, totaling 36 ears. The mean age was 68.5, with a higher prevalence of males (76%). Diabetes was present in 97% of the samples. The involvement of cranial pairs was identified in 35% of the sample. Pseudomonas aeruginosa was the most frequent pathogen isolated, found in 50% of the cases. Among the cultures with bacterial agents isolated, 35% showed resistance to ciprofloxacin. The most frequent exam was computed tomography (94%). Hospital admission was indicated for 31 patients (91%), and ceftazidime was the most prescribed drug (35.5%). There were 11 recurrences (32%), and 12 patients (35%) had complications during treatment. Among the unfavorable outcomes, 12% persisted with some degree of peripheral facial paralysis, 6% maintained dysphagia, and 9% died of the disease. Conclusions  The present study developed a diagnostic and therapeutic protocol for the effective management of necrotizing otitis externa. This protocol is a dynamic tool and should be revised and updated as new demands emerge during its implementation.

Trends and Outcomes of Fungal Temporal Bone Osteomyelitis: A Scoping Review

INTRODUCTION

Temporal bone osteomyelitis is an invasive infection most often caused by bacteria and associated with high mortality. Fungal etiologies are rare and little is known of the predictors of disease severity and outcomes in fungal temporal bone osteomyelitis.

MATERIALS AND METHODS

A scoping review was performed to determine what is known from the literature on how clinical, diagnostic, and treatment characteristics relate to patient outcomes in fungal temporal bone osteomyelitis. Using PRISMA guidelines, three databases were searched to identify all published cases of fungal temporal bone osteomyelitis. Data were extracted from each study, including clinical, diagnostic, and treatment characteristics, and outcomes.

RESULTS

Sixty-eight studies comprising 74 individual cases of fungal temporal bone osteomyelitis were included. All studies were case reports. There were high rates of diabetes, facial nerve palsy, infectious complications, and need for surgical intervention, as well as a significant delay in the evaluation and diagnosis of fungal temporal bone osteomyelitis. Disease recovery was greater in patients presenting with otorrhea, comorbid diabetes, and in those without facial nerve palsy.

DISCUSSION

Many of the defining characteristics of fungal temporal bone osteomyelitis remain unknown, and future reports should focus on determining factors that improve timely diagnosis and treatment of fungal TBO in addition to identifying prognostic indicators for outcomes and survival.

Exploring theories for the exponential 16-year rise in incidence of necrotising otitis externa in England

Background

Necrotising otitis externa is a severe, life-threatening infection. Epidemiological data demonstrate a dramatic rise in reported cases in England from 2002 to 2017. The reasons for this remain elusive.

Methods

A quantitative descriptive study was undertaken using epidemiological data from the Hospital Episode Statistics database. Cases from 2002 to 2017 were compiled and analysed. Four potential theories were explored to explain the rise in incidence.

Results

Within the 16-year period, 7327 necrotising otitis externa cases were reported. Annual necrotising otitis externa incidence increased 1142 per cent within the 16-year period, from 123 recorded cases in 2002 to 1405 cases in 2017. This correlates with an increasing prevalence of diabetes, an ageing population and likely increased physician awareness of necrotising otitis externa. There is insufficient evidence to support antibiotic resistance as a significant associated factor.

Conclusion

Correlation does not imply causation. It is likely that a combination of factors is contributing to the rise in necrotising otitis externa incidence, including increased physician recognition, diagnosis and accurate clinical coding.

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

Background

Necrotising otitis externa is a severe ear infection for which there are no established diagnostic or treatment guidelines.

Method

This study described clinical characteristics, management and outcomes for patients managed as necrotising otitis externa cases at a UK tertiary referral centre.

Results

A total of 58 (63 per cent) patients were classified as definite necrotising otitis externa cases, 31 (34 per cent) as probable cases and 3 (3 per cent) as possible cases. Median duration of intravenous and oral antimicrobial therapy was 6.0 weeks (0.49–44.9 weeks). Six per cent of patients relapsed a median of 16.4 weeks (interquartile range, 23–121) after stopping antimicrobials. Twenty-eight per cent of cases had complex disease. These patients were older (p = 0.042), had a longer duration of symptoms prior to imaging (p < 0.0001) and higher C-reactive protein at diagnosis (p = 0.005). Despite longer courses of intravenous antimicrobials (23 vs 14 days; p = 0.032), complex cases were more likely to relapse (p = 0.016).

Conclusion

A standardised case-definition of necrotising otitis externa is needed to optimise diagnosis, management and research.

Diagnostic approach to patients at risk of otogenic skull base osteomyelitis

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.

Predictive value of radiologic studies for malignant otitis externa: a systematic review and meta-analysis

OBJECTIVE

To determine the diagnostic accuracy of Necrotizing Otitis Externa (NOE) based on radiologic studies.

METHODS

The PubMed, Cochrane, Embase, Web of Science, SCOPUS, and Google Scholar databases were searched. True-positive and false-negative results were extracted for each study. Methodological quality was evaluated using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool.

RESULTS

The included studies contained data on 37 studies diagnosed with NOE. The sensitivity of gallium-67, technetium-99m, and Magnetic Resonance Imaging (MRI) was 0.9378 (0.7688-0.9856), 0.9699 (0.8839-0.9927), and 0.9417 (0.6968-0.9913), respectively. For Computed Tomography (CT), the positive criteria consisted of bony erosion alone and bony erosion plus any soft tissue abnormality. The sensitivity of CT based only on bony erosion was 0.7062 (0.5954-0.7971); it was higher 0.9572 (0.9000-0.9823) when based on bony erosion plus any soft tissue abnormality.

CONCLUSION

The diagnostic sensitivity of technetium-99m, gallium-67, and MRI was favorable. On CT, the presence of bony erosion may be a useful diagnostic marker of NOE, but the diagnostic sensitivity will be even higher if the criterion of any soft tissue abnormality is also included; however, care should be taken when interpreting the results. Our study demonstrates the potential utility of radiology studies for diagnosing NOE, but their lack of specificity must be considered, and standardized anatomic criteria are still needed.

LEVEL OF EVIDENCE

2A.

Current management of skull base osteomyelitis

PURPOSE OF REVIEW

Skull base osteomyelitis (SBO) is a life-threatening condition. Due to an aging and increasingly multimorbid population, clinicians are more often challenged with this disease. Yet, there is no consensus on the optimal diagnostic and follow-up management. This review should aid clinicians in decision-making for their patients.

RECENT FINDINGS

Treatment-resistant otalgia or headache is suspicious of SBO. Pseudomonas aeruginosa remains the most common pathogen but clinicians are challenged with increasing rates of sterile or fungal cultures due to previously applied antibiotics/steroids. No single imaging modality is able to detect the full extent of the disease. Whereas functional nuclear imaging with gallium-67 or methylene diphosphonate-technetium-99m was once advocated, its actual benefit is questionable. Newer modalities such as fluoro-D-glucose-positron emission tomography (PET)/computed tomography, PET/magnetic resonance imaging (MRI), or diffusion-weighted MRI seem to be promising in diagnosis and follow-up. Finding the causative pathogen is of utmost importance followed by long-term intravenous antibiotics until the disease has completely resolved. Surgery plays a minor role in treatment but can be helpful in selected cases.

SUMMARY

The numerous challenges in SBO render management difficult, but with a clear work-up including regular clinical, laboratory and imaging examinations, outcome can be improved.

Diagnosing necrotizing external otitis on CT and MRI: assessment of pattern of extension

BACKGROUND AND PURPOSE

Necrotizing external otitis (NEO) is a serious complication of external otitis. NEO can be classified according to-anterior, medial, posterior, intracranial, and contralateral-extension patterns. Currently there is no consensus on the optimal imaging modality for the identification of disease extension. This study compares NEO extension patterns on MR and CT to evaluate diagnostic comparability.

METHODS

Patients who received a CT and MR within a 3-month interval were retrospectively examined. Involvement of subsites and subsequent spreading patterns were assessed on both modalities by a radiologist in training and by a senior head and neck radiologist. The prevalence of extension patterns on CT and MR were calculated and compared.

RESULTS

All 21 included NEO cases showed an anterior extension pattern on CT and MR. Contrary to MR, medial extension was not recognized on CT in two out of six patients, and intracranial extension in five out of eight patients. The posterior extension pattern was not recognized on MR. Overall, single anterior extension pattern (62%) is more prevalent than multiple extension patterns (38%).

CONCLUSION

All anterior NEO extension pattern were identified on CT as well as MR. However, the medial and intracranial spreading patterns as seen on MR could only be identified on CT in a small number of patients. The posterior spreading pattern can be overlooked on MR. Thus, CT and MR are complimentary for the initial diagnosis and work-up of NEO as to correctly delineate disease extent through the skull base.

Malignant otitis externa: An updated review

Malignant otitis externa is a progressive infection of the external auditory canal and skull base. Pseudomonas aeruginosa is the most isolated microorganism and it affects mostly to diabetic, elderly, and immunocompromised individuals. Non-resolving otalgia and chronic otorrhea are the clinical manifestations presented. Facial nerve palsy is a common and well recognized complication. (Computed tomography) CT scan is useful for initial assessment, Technetium-99m is highly sensitive and is part of the protocol for diagnosis. Treatment should be individualized, with multidisciplinary cooperation among specialties. Management involves systemic antipseudomonal antibiotics and monitoring with radiologic techniques, it also involves the strict control of diabetes. It is essential to follow up the patients for at least a year post-treatment. In refractory malignant otitis externa and affection of facial nerve, surgical management is recommended. We reviewed the most recent studies on epidemiology, clinical manifestations, diagnosis, and treatment to provide an update on Malignant Otitis Externa that can offer an overview for clinical practice and future research.

Malignant Otitis External: Our Experience and Literature Review

BACKGROUND Malignant external otitis (MEO) is an invasive infection that can involve the external auditory canal and the skull base up to the contiguous soft tissues. Considering the changing face of MEO, we reviewed cases of MEO treated in our Ear Nose Throat (ENT) clinic - University Federico II of Naples between 2018 and 2019 to evaluate the current epidemiology of the condition and to assess the state of art on diagnosis, therapeutic and follow-up management in our patients. CASE REPORT We present the cases of three male patients with Type 2 diabetes mellitus who complained of long-lasting otorrhea and pain, with clinical suspicion of MEO. In all cases, ear swab was positive for Pseudomonas aeruginosa. All our patients received a 6-week course of intravenous ciprofloxacin, piperacillin, and tazobactam, with rapid clinical symptoms improvement and complete recovery at 1-year follow-up. CONCLUSIONS MEO is difficult to treat due to the lack of standardized care guidelines. Patients with MEO often present with severe otalgia, edema, otorrhea, and facial nerve paralysis. Clinicians must suspect MEO in elderly diabetic and immunocompromised patients with persistent otalgia after external otitis. Imaging (computed tomography and magnetic resonance imaging) can play synergistic roles in the management of MEO. To evaluate eradication of the disease, clinicians have to assess clinical symptoms and signs as well as radiological imaging and inflammatory markers.