Necrotizing otitis externa: a systematic review

Reassessing the Utility of Surgical Intervention for Skull Base Osteomyelitis: A 16-Year Experience

OBJECTIVE

The role of surgery in lateral skull base osteomyelitis (SBO) is controversial. Surgical intervention is often requested by consulting services in the interest of additional culture data to inform medical management. However, whether surgery alters subsequent antibiotic treatment or modifies disease outcome remains unknown. The aim of this study was to investigate the role of surgical intervention in the treatment of SBO by (1) comparing nonsurgical and surgical culture data and (2) assessing clinical outcomes and treatment course following surgical intervention.

STUDY DESIGN

Retrospective.

SETTING

Tertiary care center.

METHODS

The electronic record was queried for all patients with SBO who presented to a single institution over a 16-year period (2007-2023). Information recorded included history and exam, bedside and intraoperative culture data, antibiotic course, and disease outcomes. Primary outcome measures included change in medical management based on intraoperative cultures, recurrence rates, and mortality rates.

RESULTS

Forty patients (41 ears, average age 73 ± 13 years) met inclusion criteria. Out of 13 (32%) patients who underwent surgical intervention, one intraoperative culture changed the antibiotic course due to identification of resistance to the original antibiotic used. Surgery did not demonstrate a benefit in overall mortality (23% vs 18%, P = 0.36) or facial nerve function (33% vs 50%, P = 0.56) compared to medical management, and was associated with increased recurrence rates (54% vs 11%, P = 0.05).

CONCLUSION

Surgical cultures rarely changed antibiotic selection. Surgical debridement in treatment-refractory SBO was also not associated with improvement in recurrence or mortality rates, though this may reflect underlying differences in disease severity.

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.

Exploring the OTITIS Research Landscape Through a Scientometric Approach

Otitis media is a common health problem affecting people of all ages and significantly impacting public health and healthcare costs. Otitis media, a type of middle ear disease, is one of the most common types. This scientometric study aimed to provide an overview of the knowledge domain in otitis media research. Documents were retrieved from the Web of Science database. A scientometric study was then performed on a sample of 27,213 documents. This study found that research on otitis media has increased significantly in recent years, with an annual growth rate of 4.58%. The average age of the documents analyzed was 18 years, with an average of 21.88 citations and an average of 4.58 authors. The United States, the United Kingdom, and Japan ranked first to third in terms of number of publications. Still, the United States, China, and Sweden were in a better position in terms of impact on the research network. Co-occurrence word analysis showed that significant attention was given to topics such as chronic inflammation in autism, acute inflammation in otitis media, and increased fluid in the middle ear. This study highlights the need to prioritize and focus attention on otitis, particularly otitis media, due to its prevalence and impact on public health. The use of scientometric software, such as Biblioshiny and CiteSpace, provides a valuable means of assessing research trends and identifying important areas for future study in the field of knowledge.

Predictive role of facial nerve palsy improvement in malignant external otitis

PURPOSE

To evaluate the effects of different factors on facial nerve palsy improvement in patients with malignant external otitis (MEO) and the predictive role of improvement on MEO.

METHODS

Data were collected from all MEO patients with facial paralysis who were hospitalized between 2012 and 2017 at a tertiary referral center. We contacted patients at least 6 months after their admission to evaluate their facial nerve function and survival rate.

RESULTS

In a study of 19 samples with a mean age of 69.1 years, 9 patients (47.7%) had some or complete improvement, while 10 (52.6%) had no or very minimal improvement. In this study, there was no statistically significant difference between patients with and without facial nerve palsy improvement in terms of age, sex, usage of antifungal treatment alongside antibiotics, duration of hospital stays, HbA1c level, presentation of hearing loss and vertigo, the severity of facial palsy, comorbidity score, mean of fasting blood sugar, leukocytosis, first ESR and ESR drop, CRP and physiotherapy. We found a positive correlation between improving facial palsy and patients' survival rates.

CONCLUSION

Considering the possible influence of facial paralysis improvement prognosis on MEO patients' survival, it could affect our approach to the disease.

Necrotizing external otitis: diagnostic clues in the emergency department

PURPOSE

The assessment of necrotizing external otitis requires a high index of suspicion by the attending physician. The purpose of the study is to determine the accuracy of parameters available at the Emergency Department for the diagnosis of this pathology.

METHODS

Retrospective diagnostic accuracy study. Patients consulting at the Emergency Department for longstanding ear swelling, severe otalgia, and failure to respond to topical treatment were included. Otoscopy, physical examination, CT appearance, and analytical results were tested for the diagnosis of necrotizing external otitis, using nuclear imaging as gold standard. Sensitivity, specificity, likelihood ratios and ROC curves were calculated.

RESULTS

24 patients were included; 13 cases were necrotizing external otitis, and 11 cases were other external ear pathologies. Erythrocyte sedimentation rate and C-reactive protein levels were significantly associated with necrotizing external otitis (AUC 0.92 p < 0.001, and 0.8 p < 0.001). Positive likelihood ratios were 10.15 for values of erythrocyte sedimentation rate over 26 mm/h, and 8.25 for C-reactive protein levels over 10 mg/L. Negative likelihood ratios were 0.08 and 0.28, respectively. These results were significant. The rest of clinical and radiological parameters were less accurate.

CONCLUSIONS

Erythrocyte sedimentation rate and C-reactive protein are useful parameters in the evaluation of a case of longstanding otitis with clinical suspicion of necrotizing external otitis. If any of them is elevated, the probability of suffering this condition is significantly increased. If they are within normal ranges, an alternative diagnosis should be sought.

Management and Outcomes of Necrotizing Otitis Externa: A Retrospective Cohort Study in a Tertiary Referral Center

Objectives

Necrotizing otitis externa (NOE) is a rare infection of the ear that causes osteomyelitis. We aimed to evaluate treatment outcomes and the role of imaging in diagnosing and monitoring disease resolution in a single-center study of patients with NOE.

Methods

In this retrospective cohort study, patients with NOE who were diagnosed and treated in a tertiary otology center in Utrecht, The Netherlands, between January 1, 2013 and August 1, 2022, were included. Data were retrieved from the medical records on demographics, symptoms, physical and diagnostic findings, type and duration of treatment, and course of disease.

Results

A total of 24 cases were included. Patients were often elderly (mean age = 75 years) and diabetic (88%). Pseudomonas aeruginosa was the most commonly found microorganism (63%). Twenty-two cases (92%) received intravenous antibiotic treatment, and 7 cases (29%) received additional systemic antifungal treatment. The mean duration of systemic treatment was 29 weeks. In 20 out of 22 cases (91%), imaging was used to determine the end point of treatment. None of the cases with a total resolution of disease activity (n = 5) on 18F-fluorodeoxyglucose-positron emission tomography-computed tomography imaging at the time of cessation of therapy showed clinical relapse, compared with 1 out of 4 cases on gallium single-photon emission computerized tomography.

Conclusion

Based on the experience from our center, we demonstrated that patients with NOE can successfully be treated with prolonged systemic treatment. Molecular imaging is reasonably successful for disease evaluation and decision-making on the eradication of disease.

The Association Between Malignant Otitis Externa and Diabetes Mellitus in Africa: A Systematic Review

Diabetes mellitus is one of the risk factors for malignant otitis externa. There are very few studies on the disease in Africa and there is a need to pool the prior studies to highlight the characteristics of the disease. The study type is a systematic review and the PRISMA guidelines were followed. Using the appropriate terms, relevant medical databases were systematically searched. Thirty-two studies met the eligibility criteria with a total sample size of 848, who were mainly elderly. Diabetes mellitus was present in 94% of the participants. Average duration of diabetes diagnosis in the participants was 12.4 years. The pooled HbA1c was 9.8%. The most common symptoms were otalgia (96.1%), otorrhoea (75.8%) and hearing loss (56.1%). Pseudomonas was the most common isolate (72%). Fluoroquinolones and the 3rd-generation cephalosporins were the preferred antibiotics. The pooled cure rate from antimicrobial usage was 76.2%. In addition to medications, 24.6% of the affected individuals required debridement. About 1.6% of the participants died from malignant otitis externa. Malignant otitis externa is associated with poorly controlled diabetes. Pseudomonas is the most common cause and a significant proportion gets cured with prolonged antibiotherapy.

Skull Base Osteomyelitis: Historical Perspective, Diagnosis and Management Update

SBO is a life-threatening disease that requires a high index of suspicion based on these patients complex underlying medical co-morbidities and clinician's acumen. Once a diagnosis is made, is it critical to communicate and work closely with other multidisciplinary teams (neuroradiology for appropriate choice of imaging study and interpretation; infectious disease for appropriate medical treatment and duration; internist to properly manage their underlying medical co-morbidities). Despite advances in imaging, the diagnosis is first made based on clinical judgment, appropriate culture, and tissue biopsy.

Cranial nerve palsy prevalence and associated factors in patients with malignant otitis externa

Objective

To identify the prevalence of cranial nerve (CN) palsy and its associated factors in malignant otitis externa (MOE).

Methods

In a retrospective study, records of MOE patients from 2011 to 2014 were reviewed. MOE and CN involvement were evaluated based on patient demographics, clinical, and paraclinical data.

Results

Overall, 119 MOE patients with a mean age of 65.9 ± 11.3 were included. 69.7% were male, and 63.0% had a history of diabetes. The most common symptoms and signs were otalgia (97.5%), otorrhea (44.5%), and ear canal erythema/edema (24.4%). Thirty-three patients (27.7%) had CN involvement. The facial nerve was mostly involved (26.1%). Skull base osteomyelitis (SBO) was present in 59 patients. When excluding patients younger than 30 and older than 80, age decade was correlated with CN palsy. 66.9% of patients with CN palsy and 65.6% without CN palsy were male, which was significantly different. The following factors were not significantly different between patients with and without CN palsy: Comorbidities, signs and symptoms, diagnostic delay, erythrocyte sedimentation rate level, fasting blood sugar, hemoglobin A1c level, antifungal therapy, hospitalization duration, and SBO on imaging. Tinnitus was correlated with SBO evidence on imaging (specificity: 96.7%).

Conclusion

CN involvement occurs in about three out of 10 MOE patients. Male gender and advanced age may be related to a higher incidence rate of CN palsy. Tinnitus can be a specific indicator of SBO. These findings could help in better decision-making for early interventions.

Level of Evidence

4.

UK consensus definitions for necrotising otitis externa: a Delphi study

OBJECTIVE

To establish consensus definitions for necrotising otitis externa (NOE) to facilitate the diagnosis and exclusion of NOE in clinical practice and expedite future high-quality study of this neglected condition.

DESIGN

The work comprised of a systematic review of the literature, five iterative rounds of consultation via a Delphi process and open discussion within the collaborative. An expert panel analysed the results to produce the final outputs which were shared with and endorsed by national specialty bodies.

SETTING

Secondary care in the UK.

PARTICIPANTS

UK clinical specialists practising in infection, ear nose and throat (ENT) surgery or radiology.

MAIN OUTCOME MEASURES

Definitions and statements meeting the following criteria were accepted: (a) minimum of 70% of respondents in agreement or strong agreement with a definition/statement AND (b) <15% of respondents in disagreement or strong disagreement with a definition/statement.

RESULTS

Seventy-four UK clinicians specialising in ENT, Infection and Radiology with a special interest in NOE took part in the work which was undertaken between 2019 and 2021. The minimum response rate for a Round was 76%. Consensus criteria for all proposed case definitions, outcome definitions and consensus statements were met in the fifth round.

CONCLUSIONS

This work distills the clinical opinion of a large group of multidisciplinary specialists from across the UK to create practical definitions and statements to support clinical practice and research for NOE. This is the first step in an iterative process. Further work will seek to validate and test these definitions and inform their evolution.

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.

Dynamic Contrast-Enhanced MRI Parameters and Normalized ADC Values Could Aid Differentiation of Skull Base Osteomyelitis from Nasopharyngeal Cancer

BACKGROUND AND PURPOSE

The skull base osteomyelitis sometimes can be difficult to distinguish from nasopharyngeal cancer. This study aimed to investigate the differences between skull base osteomyelitis and nasopharyngeal cancer using dynamic contrast-enhanced MR imaging and normalized ADC values.

MATERIALS AND METHODS

This study included 8 and 12 patients with skull base osteomyelitis and nasopharyngeal cancer, respectively, who underwent dynamic contrast-enhanced MR imaging and DWI before primary treatment. Quantitative dynamic contrast-enhanced MR imaging parameters and ADC values of the ROIs were analyzed. Normalized ADC parameters were calculated by dividing the ROIs of the lesion by that of the spinal cord.

RESULTS

The rate transfer constant between extravascular extracellular space and blood plasma per minute (Kep) was significantly lower in patients with skull base osteomyelitis than in those with nasopharyngeal cancer (median, 0.43 versus 0.57; P = .04). The optimal cutoff value of Kep was 0.48 (area under the curve, 0.78; 95% CI, 0.55-1). The normalized mean ADC was significantly higher in patients with skull base osteomyelitis than in those with nasopharyngeal cancer (median, 1.90 versus 0.87; P < .001). The cutoff value of normalized mean ADC was 1.55 (area under the curve, 0.96; 95% CI, 0.87-1). The area under the curve of the combination of dynamic contrast-enhanced MR imaging parameters (Kep and extravascular extracellular space volume per unit tissue volume) was 0.89 (95% CI, 0.73-1), and the area under the curve of the combination of dynamic contrast-enhanced MR imaging parameters and normalized mean ADC value was 0.98 (95% CI, 0.93-1).

CONCLUSIONS

Quantitative dynamic contrast-enhanced MR imaging parameters and normalized ADC values may be useful in differentiating skull base osteomyelitis and nasopharyngeal cancer. The combination of dynamic contrast-enhanced MR imaging parameters and normalized ADC values outperformed each measure in isolation.

Necrotizing Otitis Concealing Carcinomas of the External Auditory Canal

External auditory canal Carcinomas are rare and aggressive tumors and their prognosis depends on early diagnosis. Their clinical similarity to necrotizing otitis is a source of error and therefore of diagnostic delay. Hence the interest of our study which consists in providing ENT specialists and all practitioners with the necessary clinical, evolutionary, radiological, biological and histological elements to avoid diagnostic errors. This is a retrospective study of all patients who were hospitalized for necrotizing otitis in the department of otolaryngology of the hospital of specialties of Rabat spread over a period of 5 years. All patients received an admission CT scan, biological tests, bacteriological sampling and biopsy. As well as initial parenteral antibiotic therapy and surgery for incidentally discovered EAC carcinomas. Clinically, all patients had otalgia and granulation tissue on otoscopic examination under the microscope. 50% had otorrhea. Pseudomonas aeruginosa was isolated in 50% of the cases, staphylococcus aureus in 25% and sterile culture in 25%. From the first biopsy, the diagnosis of tumor was retained in 6/10 patients. A second biopsy was performed in patients who did not show improvement and had a sterile culture. This one allowed the diagnosis in 4 other patients. All our patients had a surgical indication and were operated and then irradiated. The survival at 5 years was 50%. Biopsy must be systematic for every patient hospitalize for necrotizing otitis. Without hesitating to do it again each time the evolution is not good and the culture is sterile.

CT findings in temporal bone sites in skull base osteomyelitis from malignant otitis externa

OBJECTIVES

To identify the earliest sites and spread patterns of bony erosions on high-resolution temporal bone computerized tomographic (HRTBCT) scans and conjugate the radiological findings with clinical/laboratory data for guiding the interpretation of CT images of skull base osteomyelitis (SBOM) from malignant otitis externa (MOE).

STUDY DESIGN

Retrospective and prospective medical records analysis.

METHODS

The medical records of all patients who presented to a referral medical center during 2015-2022 and initially diagnosed with SBOM. Radiological assessment of each sub-site was performed by 2 qualified neuro-radiologist, who were blind to the clinical data.

RESULTS

33 patients were enrolled. All patients suffered edema and exudates of the external auditory canal (EAC). The most common osseous markers for SBOM were dehiscence or irregularity of the anterior EAC wall and temporomandibular joint (TMJ) medial wall (21/33, 64% patients, each), followed by a fistula from the TMJ to the EAC (20/33, 61% patients). Eustachian tube bony walls and condylar irregularity and/or dehiscence were as prevalent as 16/33, 48% of patients, each. EAC inferior and posterior walls of the EACs were irregular or dehiscent in patients with more advanced disease.

CONCLUSIONS

The high symptomatologic overlap between SBOM and other aural pathologies might cause diagnostic (and subsequent treatment) delay and result in dire complications. EAC edema and irregularity or dehiscence of the anterior EAC wall are the most common early CT findings associated with SBOM caused by MOE.

LEVEL OF EVIDENCE: 4

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.

Magnetic Resonance Imaging of Head and Neck Emergencies, a Symptom-Based Review, Part 2: Ear Pain, Face Pain, and Fever

The use of magnetic resonance (MR) imaging in the emergency department continues to increase. Although computed tomography is the first-line imaging modality for most head and neck emergencies, MR is superior in some situations and imparts no ionizing radiation. This article provides a symptom-based approach to nontraumatic head and neck pathologic conditions most relevant to emergency head and neck MR imaging, emphasizing relevant anatomy, "do not miss" findings affecting clinical management, and features that may aid differentiation from potential mimics. Essential MR sequences and strategies for obtaining high-quality images when faced with patient motion and other technical challenges are also discussed.

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.

Necrotising Otitis Externa - is poor outcome predictable? The application of a diagnosis-based scoring system in patients with skull base osteomyelitis

Background

The increased incidence of necrotising otitis externa over the last decade has had a significant burden on healthcare providers. Several factors may affect outcome, and stratifying risk may allow personalised treatment.

Method

Retrospectively identified patients were prospectively surveyed over 12 months. The Cox proportional hazards model was used to identify predictors of poor prognosis.

Results

Twenty-six patients with necrotising otitis externa (average age of 80 years) were admitted from 2018 to 2019. At one year, 19 per cent mortality was observed. A high Charlson Comorbidity Index was associated with increased mortality (p = 0.03), prolonged in-patient stay (p = 0.047) and increased odds of adverse outcomes (odds ratio = 1.48, 95 per cent confidence interval = 0.26–2.67, p = 0.019). The Charlson Comorbidity Index in our prognostic model was validated using the receiver operating characteristic curve (area under the curve = 0.76). Charlson Comorbidity Index score of 5 or more independently predicted one-year morbidity and mortality (hazard ratio = 1.30, 95 per cent confidence interval = 0.94–1.79, p = 0.03).

Conclusion

Risk-stratifying patients may enable clinicians to holistically counsel patients and tailor their treatment to improve their prognosis and subsequently alleviate the burden of necrotising otitis externa.

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.

Imaging of Acute and Chronic Skull Base Infection

Skull base infections are uncommon but can be life threatening without timely recognition. Imaging plays a crucial role because symptoms can be vague and nonlocalizing. Necrotizing otitis externa in diabetic or immunocompromised patients is the commonest cause of skull base osteomyelitis (SBO), followed by sinogenic infections and idiopathic central SBO. Multiparametric magnetic resonance (MR) and high-resolution CT are the mainstays for establishing a diagnosis and estimating disease extent, with MR being superior in ascertaining marrow and soft tissue involvement. Monitoring treatment response, of which imaging is a fundamental part, is challenging, with emerging promising imaging tools.

Skull base osteomyelitis imaging

PURPOSE OF REVIEW

Skull base osteomyelitis (SBO) is a challenging entity to diagnose and treat. The goal of this review is to summarize the imaging findings of SBO and present these in the context of recent studies on imaging of SBO.

RECENT FINDINGS

This review discusses the clinical presentation, pathophysiology and imaging appearances of SBO. The review further emphasizes the results of latest studies on imaging of SBO, and the role of different modalities in diagnosis and evaluation of disease course and treatment response. Brief discussion on differential diagnoses from an imaging standpoint is also included.

SUMMARY

Various imaging modalities play different and complimentary roles in diagnosis and management of SBO, which are discussed in this review.

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.

Hyperbaric oxygen therapy in malignant otitis externa: A systematic review of the literature

OBJECTIVE

To review the role of adjuvant hyperbaric oxygen therapy (HBOT) in the treatment of malignant otitis externa (MOE).

DATA SOURCES

PubMed, Scopus, Web of Science, Science Direct, and Cochrane Library were searched for the following concepts: "hyperbaric oxygen" and "malignant or necrotizing otitis externa."

METHODS

Studies were included if they contained (1) patients with reported evidence of MOE, (2) employment of adjuvant HBOT, (3) details on patients' medical condition, and (4) documented survival outcomes. Extracted information included patient demographics, underlying medical conditions, infectious etiology, signs and symptoms, medical and surgical treatments, duration of medical treatment, mean follow up time, HBOT setting, number of HBOT sessions, complications, survival rate, and all-cause mortality.

RESULTS

A total of 16 studies comprising 58 patients (mean age 68.0 years) were included. Diabetes was present in 94.7% of cases and Pseudomonas spp (64.3%) was the most common infectious agent. Cranial nerve VII was involved in 55.2% of cases. Overall, the disease cure rate with adjuvant HBOT was 91.4% and all-cause mortality was 8.6%. Among those who had cranial nerve VII involvement, 72.0% had return of function and 93.8% of them survived.

CONCLUSION

HBOT may be an effective treatment option for refractory or advanced MOE but its efficacy remains unproven due to lack of strong scientific evidence. However, its therapeutic value should not be underestimated given good results and few adverse events reported in this study.

Diabetes and glycemic control in necrotizing otitis externa (NOE)

PURPOSE

Although the association between necrotizing otitis externa (NOE) and diabetes mellitus (DM) is well known, there is little knowledge in regards to the effects of DM and glycemic control on the outcome of NOE. The aim of the study was to determine the effects of DM duration and glycemic control, and in-hospital glycemic control on NOE severity.

METHODS

A retrospective case series analysis, including all patients hospitalized between 1990 and 2018 due to NOE were included. Data collected included NOE disease characteristics, duration of DM, DM-associated comorbidities, glycated hemoglobin (HbA1c), urine microalbumin and in-hospital blood glucose measurements. Disease severity was defined based on duration of hospitalization (above or below 20 days) and need for surgery.

RESULTS

Eighty-nine patients were included in the study. Eighty-three patients (94.3%) had DM. Preadmission HbA1c was 8.13% (5.8-12.6%). Forty-nine patients (65.5%) had mean blood glucose of ≥ 140 mg/dL and 26 (34.5%) had ≤ 140 mg/dL. DM duration was 157.88 months among NOE patients who required surgery, and 127.6 months among patients who were treated conservatively (p value 0.25). HbA1c in patients hospitalized < 20 days was 7.6%, and 8.7% among NOE hospitalized ≥ 20 days (p value 0.027). Seven patients with mean blood glucose of ≤ 140 mg/dL had Pseudomonas Aeruginosa (PA-NOE) (26.7%), in comparison to 25 (51.0%) with mean blood glucose measurement of ≥ 140 mg/dL (p = 0.045).

CONCLUSIONS

HbA1c at admission is associated with longer hospitalization duration among NOE patients. Mean blood glucose during hospitalization was associated with a higher likelihood of PA infection, however, it had no effect on disease outcome.

Rare Diseases of the Middle Ear and Lateral Skull Base

Otalgia, otorrhea and hearing loss are the most common ear-related symptoms that lead to the consultation of an otolaryngologist. Furthermore, balance disorders and affections of the cranial nerve function may play a role in the consultation. In large academic centres, but also in primary care, the identification of rare diseases of the middle ear and the lateral skull base is essential, as these diseases often require interdisciplinary approaches to establish the correct diagnosis and to initiate safe and adequate treatments. This review provides an overview of rare bone, neoplastic, haematological, autoimmunological and infectious disorders as well as malformations that may manifest in the middle ear and the lateral skull base. Knowledge of rare disorders is an essential factor ensuring the quality of patient care, in particular surgical procedures. Notably, in untypical, complicated, and prolonged disease courses, rare differential diagnoses need to be considered.

Prognosticating patients with necrotising otitis externa based on response to treatment

INTRODUCTION

Necrotising otitis externa (NOE) is a severe infection of the temporal bone. The traditional severity based staging system does not fully prognosticate all patients with NOE. We hypothesise that a patient response staging system would more accurately capture the disease process and guide prognosis.

METHODS

We carried out a retrospective notes review of patients diagnosed with NOE from January 2017 to December 2018 in a regional tertiary referral centre. Patient outcomes from our proposed patient response staging system were compared to a modified previously published severity based Gleeson staging system with patients requiring prolonged treatment classified as having a poor outcome.

RESULTS

A total of 34 patients were treated for NOE. The majority were male (n=24) and had diabetes (n=25). Patients with the most severe Gleeson staging did not have the worst outcome. Daily delay in resolution of otorrhoea was associated with an increased need for more than six weeks of treatment. Rapid responders are patients who had resolution of otalgia, otorrhoea and C-reactive protein normalisation within 14 days, and all were cured following standard 6 weeks of treatment.

CONCLUSIONS

The Gleeson staging system was valuable in assessing the extent of disease and all early Gleeson staged patients had good outcomes. However, patients with higher severity staging on the Gleeson system did not necessarily require prolonged treatment. There is a role for a joint approach in staging patients based on both modified Gleeson and treatment response, which would subsequently guide prognosis, duration of treatment and early diagnosis of potential fungal NOE.

Skull Base Osteomyelitis: A Comprehensive Imaging Review

Skull base osteomyelitis is a relatively rare condition, generally occurring as a complication of advanced otologic or sinus infection in immunocompromised patients. Skull base osteomyelitis is generally divided into 2 broad categories: typical and atypical. Typical skull base osteomyelitis occurs secondary to uncontrolled infection of the temporal bone region, most often from necrotizing external otitis caused by Pseudomonas aeruginosa in a patient with diabetes. Atypical skull base osteomyelitis occurs in the absence of obvious temporal bone infection or external auditory canal infection. It may be secondary to advanced sinusitis or deep face infection or might occur in the absence of a known local source of infection. Atypical skull base osteomyelitis preferentially affects the central skull base and can be caused by bacterial or fungal infections. Clinically, typical skull base osteomyelitis presents with signs and symptoms of otitis externa or other temporal bone infection. Both typical and atypical forms can produce nonspecific symptoms including headache and fever, and progress to cranial neuropathies and meningitis. Early diagnosis can be difficult both clinically and radiologically, and the diagnosis is often delayed. Radiologic evaluation plays a critical role in the diagnosis of skull base osteomyelitis, with CT and MR imaging serving complementary roles. CT best demonstrates cortical and trabecular destruction of bone. MR imaging is best for determining the overall extent of disease and best demonstrates involvement of marrow space and extraosseous soft tissue. Nuclear medicine studies can also be contributory to diagnosis and follow-up. The goal of this article was to review the basic pathophysiology, clinical findings, and key radiologic features of skull base osteomyelitis.

Conservative management of petrous apex abscess and Gradenigo's syndrome in a diabetic patient: Case report and literature review

The case reported evidences the possibility of nonsurgical treatment in patients with abscesses located in regions difficult to reach surgically due to surgical limitations or possible sequelae related to surgical procedure.

Computer tomography findings in necrotizing otitis externa based on the offending pathogens

PURPOSE

High-resolution temporal bone computer tomography (HRTBCT) is the most common initial radiological modality used for the assessment of necrotizing otitis externa (NOE).

OBJECTIVES

(1) To compare the extension of disease, as seen on HRTBCT, in patients with NOE caused by different pathogens and (2) assess whether radiological findings may suggest the offending pathogen in cases of sterile-NOE.

METHODS

All NOE patients were hospitalized between 1990 and 2018. All patients underwent HRTBCT at admission. Three groups (fungus-NOE, PA-NOE and sterile-NOE) comprising of ten patients each were randomly selected. HRTBCT was reevaluated by a senior radiologist. Thirteen radiological subsites were selected for reevaluation.

RESULTS

All patients in the fungal-NOE group complained of otalgia, compared to nine in the sterile-NOE and six in the PA-NOE groups (p value = 0.044). External ear canal edema and granulation tissue were the most common findings in all groups. Surgery was performed in five patients in the fungal-NOE and PA-NOE and three in the sterile-NOE group (p value =  > 0.05). Radiological findings indicating severe bone erosion within the EEC was seen in all patients but 3 (p value =  > 0.05). Severe TMJ erosion was seen in one patient within the fungal-NOE and PA-NOE group (p value =  > 0.05). When mild and severe involvement were combined, TMJ bone erosion was seen in four patients in the fungal-NOE and only in one patient in the PA-NOE (p = 0.04).

CONCLUSIONS

TMJ involvement may be more common in fungal disease, suggesting a different spreading pathway, as opposed to PA-NOE. Accordingly, TMJ involvement on HRTBCT may justify antifungal treatment in sterile culture-NOE.

Multiple cranial nerve palsies in malignant external otitis: A rare presentation of a rare condition

Malignant external otitis (MEO) is a rare inflammatory and infectious condition, typically caused by Pseudomonas aeruginosa, that mainly affects diabetic or immunocompromised elderly patients and is associated with severe morbidity and mortality. It begins in the external auditory canal and rapidly progresses through the skull base, leading to osteomyelitis and may result in cranial neuropathy, especially of the facial nerve. Here we describe a rare neurological presentation of MEO in a 65-year old diabetic man, who presented with an 8-month progressing left otitis externa and evolved with ipsilateral proptosis, ophthalmoplegia, blindness, facial palsy, hearing loss and contralateral evolvement of the temporal bone with hearing impairment. He was initially treated with oral ciprofloxacin and after one week was transferred to our tertiary hospital, where antibiotic therapy was switched to meropenem and vancomycin due to the severity of the case and to the hospital's microbiological profile. The patient underwent left canal wall-up mastoidectomy with insertion of ear ventilation tube bilaterally, with good recovery of right ear hearing capacity, but with no improvements of neurological deficits nor left hearing function. All microbiological tests performed were negative, and this was interpreted as a possible consequence of the early use of antibiotics. Unfortunately, the patient was infected by Sars-CoV-2 during hospitalization and passed away after ten days of COVID-19 intensive care unit internment.

Necrotising otitis externa: A single centre experience

Introduction

Necrotising otitis externa (NOE) is a rare infection of the ear canal with frequent bone erosion. This study’s objective is to describe the different features of NOE as well as its management in an ear-nose-throat department. We also tried to identify the particularities of the fungal infection.

Patients and methods

It is an observational cohort that included all the patients hospitalised for the management of NOE. The study was carried out in the ear-nose-throat Department of Mahdia University Hospital in Tunisia between January 2006 and december 2019.

Results

A total of 40 patients were included. The mean age was 65 ± 12.9 years and the sex ratio was 0.9. Ninety percent of the patients included were diabetics. The most common signs found were oedema of the external canal (97.5%) and auricular discharge (92.5%). The main pathogen isolated was Pseudomonas aeruginosa (61.7%). Fungi were isolated in 9 cases (26.47%). Computed tomography was performed for 32 patients (80%). Bone erosion was seen in 26 cases (81.3%). The main complications were cerebral venous thrombosis, retropharyngeal abscess and cerebral empyema. Thirty one patients received only antibiotics, 2 received only antifungal treatment, and 7 received both antibiotics and antifungal treatment. All patients had a favorable outcome. Univariate analysis showed a higher median erythrocyte sedimentation rate was associated with fungal infections. No other differences were noted.

Conclusion

Our management protocol seems to be efficient since all patients had initial favorable outcome. A higher median erythrocyte sedimentation rate was associated with fungal infections.

•

Necrotising otitis externa has a variable clinical presentation and a relatively high rate of complications.

•

The patients were mainly diabetics or aged more than 65 years old.

•

The main pathogen isolated was Pseudomonas aeruginosa.

•

A higher median erythrocyte sedimentation rate was associated with fungal infections.

Incidence and Risk of Various Disorders of the External Ear in Patients With Hearing Aids Treated in ENT Practices in Germany

OBJECTIVE

The aim of the study was to investigate the relationship between the presence of a hearing aid (HA) and the occurrence of various disorders of the external ear, using data from ear, nose, and throat (ENT) practices in Germany from a nationwide, representative practice database.

METHODS

In the period between 2012 and 2016, the incidences of disorders of the external ear (ICD-10 groups H60 and H61) in patients with HA prescriptions were compared retrospectively with a control group without HA prescriptions (1:1 matching).

RESULTS

A total of 20,127 patients with HA prescriptions were compared with 20,127 controls. The highest 12-month incidences (HA vs. controls) were determined for "Impacted cerumen" (H61.2) (16.5% vs. 4.2%), "Unspecified otitis externa" (H60.9) (2.6% vs. 1.2%) and 'Acute noninfective otitis externa' (H60.5) (2.3% vs. 0.7%). The most significant risk increases for HA wearers were found for "Abscess of external ear' (H60.0, OR 10.03), "Other otitis externa' (H60.8, OR 6.00), and "Impacted cerumen' (H61.2, OR 4.55). A smaller risk increase was found for "Cholesteatoma of external ear' (H60.4, OR 2.26), among others.

CONCLUSION

In HA wearers, the risk of developing almost all of the diagnoses reviewed is significantly increased, especially for external auditory canal (EAC) furuncle, chronic otitis externa, and impacted cerumen. This study provides the first epidemiological evidence for HA as a risk factor for the rare EAC cholesteatoma.

Otitis Externa

BACKGROUND

Otitis externa has a lifetime prevalence of 10% and can arise in acute, chronic, and necrotizing forms.

METHODS

This review is based on publications retrieved by a selective search of the pertinent literature.

RESULTS

The treatment of acute otitis media consists of anal- gesia, cleansing of the external auditory canal, and the appli- cation of antiseptic and antimicrobial agents. Local antibiotic and corticosteroid preparations have been found useful, but there have been no large-scale randomized controlled trials of their use. Topical antimicrobial treatments lead to a higher cure rate than placebo, and corticosteroid preparations lessen swelling, erythema, and secretions. Oral antibiotics are indi- cated if the infection has spread beyond the ear canal or in patients with poorly controlled diabetes mellitus or immuno- suppression. Chronic otitis externa is often due to an under- lying skin disease. Malignant otitis externa, a destructive infection of the external auditory canal in which there is also osteomyelitis of the petrous bone, arises mainly in elderly diabetic or immunosuppressed patients and can be life- threatening.

CONCLUSION

With correct assessment of the different types of otitis externa, rapidly effective targeted treatment can be initi- ated, so that complications will be avoided and fewer cases will progress to chronic disease.

The role of imaging in skull base osteomyelitis - Reviewed

PURPOSE

Skull base osteomyelitis (SBO) is difficult to diagnose due to a wide array of clinical presentations. It can be life threatening if not treated promptly. The objective of this study is to identify the various neck spaces involved in skull base osteomyelitis, correlate them with the possible source of infection and identify the related complications.

METHODS

Eighty nine consecutive either culture proven cases of skull base osteomyelitis, or culture negative cases with inflammation on histopathology responding to antibiotic therapy, presenting at a single non-government hospital in south India between January 2016 and December 2018 were included in this study. Images were reviewed by two radiologists and imaging findings were documented by consensus.

RESULTS

Involvement of the parotid space, retromastoid space and (temporomandibular) TM joint was associated with otogenic source of infection (p value < 0.05); while, retropharyngeal/prevertebral involvement was associated with sphenoid and nasopharyngeal sources (p value < 0.05). Complications such as cavernous sinus thrombosis (p value = 0.023) and ICA involvement (p value = 0.014) were more commonly seen with central skull base osteomyelitis. Abscess formation was seen in all three groups of patients without a significant difference between the groups.

CONCLUSION

Imaging plays an important role in determining the possible source of infection by identifying the involved neck spaces and this in turn can guide the clinician to a site for biopsy. Complications related to SBO can also be identified on imaging and can guide appropriate management.

Malignant Otitis Externa: Causes for Various Treatment Responses

OBJECTIVES

Malignant (necrotizing) otitis externa (MOE) is an aggressive form of skin inflammation of the external ear with a tendency to spread infection to the temporal bone. The study aimed to evaluate a causal relationship between treatment responses and clinical features in patients with MOE.

MATERIALS AND METHODS

In a retrospective, descriptive section study, the database was analyzed between January 2008 and December 2018 in our department, all patients with diagnosed MOE were identified.

RESULTS

A total of 30 patients were evaluated, of which 27 men and 3 women. The youngest patient was 52 years old while he was eldest 88 years, (mean-71 years old). As the most common comorbidity, diabetes mellitus was found in 23 (76%) subjects. Median duration of symptoms was about 3 months. The most common isolated pathogen was Pseudomonas aeruginosa (47%). Patients with facial nerve palsy and erosion of temporal bone find on computerized tomography affect prolonged stationary treatment (Mean, SD 29.2±8.5 and 26,7±11.6 days), while 80% of patients with facial nerve palsy had recurrence of disease (p=0.005) with mean duration of clinical remission of 60±17.3 days. Overall length of treatment is also increased in the presence of comorbidities as well as in patients with cranial nerve involvement.

CONCLUSION

Patients with cranial nerve involvement, erosion of temporal bone and presence of comorbidities affect prolonged treatment and adverse prognosis. Early diagnosis and initiation of aggressive therapy are essential for stopping the further spread of the disease and prevention of serious complications.

Necrotizing Otitis Externa-Analysis of 83 Cases: Clinical Findings and Course of Disease

OBJECTIVES

Evaluate the relationship between clinical findings and course of disease among patients with necrotizing otitis externa (NOE).

STUDY DESIGN

Retrospective case series review.

SETTING

Tertiary referral center.

PATIENTS

Adult patients with no previous history of chronic ear disease, hospitalized due to NOE between the years 1990 to 2015.

MAIN OUTCOME MEASURES

1) Duration of hospitalization and 2) necessity for surgery.

RESULTS

Eighty-one patients were included in the study, corresponding to 83 effected ears. Thirty-two patients (38.5%) were hospitalized longer than 20 days and 20 patients (24.0%) underwent surgery. Otalgia was the most common complaint (n = 71, 85.5%). Pseudomonas Aeruginosa (PA) was the most common isolated bacteria (n = 40, 48.1%). Shifting incidence of culture results was noted, as rates of PA NOE decreased and rates of sterile culture and fungal NOE increased. Duration of complaints and presence of aural discharge at admission were associated with prolonged hospitalization (p = 0.010, p = 0.011, respectively). Advanced age, duration of hospitalization, and rates of readmission were associated with surgery (p = 0.037, p < 0.001, p < 0.001 respectively).

CONCLUSIONS

Duration of complaints and presence of aural discharge may indicate advanced NOE and require longer in-hospital treatment. Elderly patients are at increased risk for conservative treatment failure and are more likely to require surgery. With shifting incidence of pathogens, a wider empirical treatment covering nontraditional pathogens should be considered.

Imaging in the Diagnosis and Management of Necrotizing Otitis Externa: A Survey of Practice Patterns

OBJECTIVE

To survey neurotologists and head and neck radiologists regarding use of imaging in the diagnosis and management of necrotizing otitis externa (NOE).

STUDY DESIGN

Cross-sectional survey study.

SETTING

Online survey distributed through email to specialty society membership lists.

PARTICIPANTS

Neurotologists and head and neck radiologists with membership in either the American Neurotology Society or The American Society of Head and Neck Radiology.

MAIN OUTCOME MEASURES

Responses to survey consisting of two demographic and seven clinically oriented questions related to the use of imaging in the diagnosis and management of NOE.

RESULTS

One hundred thirty-six participants responded to the survey. The imaging modality of choice in establishing the diagnosis of NOE selected by the respondents was computed tomography (CT) (37.5%) followed by technetium scintigraphy (21.3%). Magnetic resonance imaging (MRI) was the preferred investigation by 41.9% of participants for determining extent of disease. Gallium scanning was the imaging modality preferred by 32.4% of respondents for determining when to cease medical therapy. Ninety-five percent of participants responded that CT scans were always or frequently used in the diagnosis and management of NOE compared with 72.8% for MRI, 34.5% for gallium scans, and 34.2% for technetium scans.

CONCLUSIONS

There is considerable heterogeneity in the preferred imaging modalities used in the diagnosis and management of NOE. CT and MRI are the preferred contemporary modalities used by many physicians, demonstrating a shift away from the historic use of nuclear medicine scans.

Stenotrophomonas skull base osteomyelitis presenting as necrotizing otitis externa: Unmasking by CT and MRI-case report and review

Necrotizing or malignant otitis externa in patients presenting with mild clinical findings can pose as a tip of the iceberg; computed tomography (CT) and/or magnetic resonance imaging (MRI) unveils the clinical-imaging discrepancy and unmasks the presence of skull-base osteomyelitis (SBO). Pseudomonas aeruginosa is the most common causative pathogen of SBO, followed by fungal and other rare bacterial organisms. This report presents a rare case in an elderly diabetic patient, where the pathogen Stenotrophomonas maltophilia was isolated. There have been no previous reported cases in the literature of SBO caused by this pathogen. The hallmark of SBO on computed tomography or magnetic resonance imaging is soft tissue inflammatory changes under the central skull base with associated bone erosion. This may result in the peculiar appearance of the "Ovoid Gap" sign. SBO can be due to nonotogenic sources, namely: sinogenic, rhinogenic, pharnygogenic, or odontogenic infections. Low threshold for imaging is advised in immunosuppressed and elderly diabetic patients.

A Persistent Foramen of Huschke: A Small Road to Misery in Necrotizing External Otitis

BACKGROUND AND PURPOSE

Necrotizing external otitis is a serious complication of external otitis with different spreading patterns. A persistent foramen of Huschke is a dehiscence located antero-inferior in the osseous external ear canal and posterior-medial to the temporomandibular joint. This dehiscence can facilitate extension of infection in an anterior pattern next to classic spread along the fissures of Santorini. The aim of this study was to define the prevalence and size of a persistent foramen of Huschke in patients with necrotizing external otitis.

MATERIALS AND METHODS

We retrospectively examined 78 CT temporal bone studies (39 patients with necrotizing external otitis, 39 control subjects). The side and presence of the foramen were noted, and its prevalence was calculated. The maximal width of the foramen of Huschke was measured in the axial plane and classified as subtle, mild, moderate, or extensive.

RESULTS

A persistent foramen of Huschke was present in 21 patients (26 ears) and 7 control subjects (9 ears). Prevalence was 50% (20/40) and 11.5% (9/78) in affected ears of patients with necrotizing external otitis and control subjects, respectively. Almost all affected ears showed an anterior distribution pattern of necrotizing external otitis. The extensive dehiscence was most common in affected ears.

CONCLUSIONS

An anterior necrotizing external otitis spreading pattern is associated with the presence and increased size of a persistent foramen of Huschke. These findings facilitate the theory that a persistent foramen of Huschke is an additional risk factor the development of necrotizing external otitis.