Central skull base osteomyelitis: new insights and implications for diagnosis and treatment

A case report of Transnasal Endoscopic Drainage for Upper Parapharyngeal Abscess

We report a case of upper parapharyngeal abscess arising from progression of a central skull base osteomyelitis, in a patient with poorly controlled diabetes mellitus. Our case is unusual for its presentation in an upper parapharyngeal location, involvement of the skull base, and poor response to medical treatment, hence requiring transnasal endoscopic surgical drainage to achieve definitive treatment. Here, we share our experience with a safe and effective technique of transnasal endoscopic drainage of a parapharyngeal abscess. Laryngoscope, 2024.

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.

Endoscopic Transnasal Navigation Guided Treatment of Clivus Abscess in Adult with Mucormycosis: A Rare Report

Osteomyelitis and abscess of the clivus are rare conditions thought to arise from contiguous spread of infection from the paranasal sinuses. Clival osteomyelitis is a rare potentially life-threatening skull base infection which is generally challenging to diagnose and treat. It is typically seen in the pediatric population and is very rare in the adult population. The exact pathophysiology of osteomyelitis of the clivus is relatively uncertain. Here, we describe a case of a 32-year-old immunocompetent female with a primary complaint of headache, with no significant medical history of diabetes, hypertension or rhinosinusitis or SARS COV-2 for the past 18 months. This case report demonstrates an image-guided and endoscopic approach to surgical localization and treatment of abscesses in the clival area.

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.

Atypical Skull-Base Osteomyelitis: Comprehensive Review and Multidisciplinary Management Viewpoints

Atypical skull-base osteomyelitis is a rare but fatal disease that usually involves infection of the ethmoid, sphenoid, occipital, or temporal bones that form the skull base. Unlike typical (so-called otogenic), atypical skull-base osteomyelitis has no otogenic cause. Instead, some authors call atypical skull-base osteomyelitis sinonasal, since the infection most often originates from the nose and paranasal sinuses. Diagnosing and treating this disease is challenging. To assist in managing atypical skull-base osteomyelitis, a review of the most recent literature, with patient cases and multidisciplinary perspectives from otolaryngologists, neurosurgeons, radiologists, infectious disease specialists, pathologists, and clinical microbiologists, is provided in this paper.

Observational Study on Clinical Features and Management of Skull Base Osteomyelitis in Hospitalised Patients at a Tertiary Care Hospital

1. To study the various clinical presentations, microbiological and radiological profiles in patients of skull base osteomyelitis, to know about the underlying comorbidities or immunocompromised status and its relation to the disease and its management. 2. To study the effect of long term intravenous antimicrobial therapy with respect to clinical outcomes and radiological improvement and to study the long term outcomes of the treatment. This is an observational prospective and retrospective study. Thirty adult patients who were diagnosed with skull base osteomyelitis by clinical/microbiological and or radiological features were treated with long term intravenous antibiotics according to pus culture and s for 6-8 weeks and they were followed up for 6 months. Clinical improvement in symptoms and signs, radiological imaging features and pain score were assessed after 3 and 6 months. We noticed in our study that skull base osteomyelitis are more common in older patients with male predominance. Presenting symptoms include ear discharge, otalgia, hearing, cranial nerve palsy. Immunocompromised state, mainly Diabetes mellitus is closely associated with skull base osteomyelitis. Majority of patients showed Pseudomonas related species on pus culture and sensitivity. All the patients showed temporal bone involvement in CT and MRI. Other bones involved were shenoid, clivus and occipital bone. Majority showed good clinical response to intravenous ceftazidime, combination of piperacillin and tazobactum, followed by combination of piptaz and Ciprofloxacin. Treatment duration was 6-8 weeks. All patients showed clinical improvement in symptoms and relief in pain after 3 and 6 months. Skull base osteomyelitis is a rare condition, most commonly seen in elderly patients with diabetes mellitus and or other immunocompromised condition. Pseudomonas related species are the major causes of skull base osteomyelitis. Long term pus culture and sensitivity bases intravenous antibiotic therapy is the main stay of treatment.

Predictive factors in treatment response of malignant external otitis

PURPOSE

To evaluate the prevalence and impact of various predictive factors including diabetes control in malignant external otitis (MEO) treatment response.

METHODS

In a cross-sectional study on MEO patients, we defined treatment response with three indices; ESR level decrease, hospitalization period, and systemic antifungal drug usage. The impact of diabetes control and other predictive factors on these indices have been evaluated.

RESULTS

Overall, 164 patients with a mean age of 67.8 ± 9.7 years were included. Cranial nerve involvement was present in 56 patients. Nine patients had immunodeficiency. 19.5% of cases had leukocytosis. Diabetes mellitus was present in 156 patients, suffering for an average of 13.9 ± 8.6 years. The overall mean hemoglobin A1C (HbA1c) level was 8.3% (4.4-12.8%), and the mean fasting blood sugar was 146.4 mg/dl (63-292 mg/dl). 29.3% of patients had good diabetes control before admission (HbA1c < 7%), 54.9% had poor control (7% < HbA1c < 10%) and 15.9% had very poor glycemic control (HbA1c > 10%). The predictive role for the following factors were not statistically significant: age, gender, comorbidities, diabetes, diabetes management method used before and during hospitalization, diabetes duration, leukocytosis, immunodeficiency, fasting blood sugar level, HbA1c level, glycemic control index, and insulin amount. However, CRP level with a mean value of 34.3 mg/L showed a significant correlation with ESR decrease, hospitalization period, and antifungal drug usage.

CONCLUSION

CRP level could be used as a predictor for the hospitalization period, the need for systemic antifungal and ESR level decrease. It would be helpful to check the CRP level at the time of diagnosis to predict the hospitalization period and the necessity of systemic antifungal management to adjust the treatment strategy.

A Fatal Case of Meningitis Complicating Chronic Otitis Media and Base of Skull Osteomyelitis due to Carbapenemase (OXA-48)-Producing Klebsiella pneumoniae

Osteomyelitis of the base of the skull is a rare but life-threatening disease. Although Klebsiella pneumoniae is not a pathogen that is frequently associated with this infection, the clinical course can rapidly progress to meningitis. Here, we describe a case of chronic otitis media, secondary to OXA-48K. pneumoniae, which was complicated by osteomyelitis of the base of the skull and fatal meningitis.

Mycotic clival osteomyelitis secondary to immunosuppression by SARS-CoV-2

Background:

During the past 2 years, the use of systemic corticosteroids has increased due to COVID-19 atypical pneumonia management. Similarly, an increase in mycotic infection cases has been reported during the same period as a consequence of immunosuppression caused by corticosteroid overuse. Mycotic clival osteomyelitis is a rare clinical entity which presumably has increased its incidence during the pandemic.

Case Description:

A 52-year-old woman who presented persistent headaches and unexplained weight loss after being hospitalized due to COVID-19 pneumonia treated with intravenous corticosteroids. Head computed tomography and magnetic resonance imaging showed extensive osteomyelitis at the clival region with no brain parenchyma involvement. Surgical excision through navigation-guided transnasal transclival endoscopic extended approach was performed for surgical debridement. Histopathological analysis revealed angulated hyphae, suggestive of Aspergillosis. Systemic antifungal treatment was administered for 30 consecutive days. Afterward, she was discharged without any remarkable neurological findings, reassessed during follow-up.

Conclusion:

The COVID-19 pandemic has had an effect on the reemergence of mycotic infections due to corticosteroid immunosuppression. Clival osteomyelitis secondary to mycotic infection is an exclusion diagnosis that we encourage to be highly suspected within the persisting COVID-19 pandemic.

Optimal Diagnostic Criteria and a Staging System for Otogenic Skull Base Osteomyelitis

Objective  Diagnostic criteria for otogenic skull base osteomyelitis (SBO) have been conflicting among researchers. We aimed to propose clinically useful diagnostic criteria and a staging system for otogenic SBO that is associated with infection control and mortality. Design  The present study is designed as a retrospective one. Setting  This study was conducted at the University Hospital. Participants  Thirteen patients with otogenic SBO who met the novel rigorous diagnostic criteria consisted of symptomatic and radiological signs on high-resolution computed tomography (HRCT) and magnetic resonance imaging (MRI). Simple refractory external otitis was not included. A staging system according to disease extent revealed by HRCT and MRI is proposed: lesions limited to the temporal bone (stage 1), extending to less than half (stage 2), exceeding the midline (stage 3), and extending to the whole of the clivus (stage 4). All patients received long-term antibiotic therapy. Patients were divided into infection-uncontrolled or -controlled groups based on symptoms, otoscopic findings, and C-reactive protein level at the last follow-up. The mean follow-up period was 27.7 months. Main Outcome Measures  Possible prognostic factors, such as immunocompromised status and symptoms, including cranial nerve palsy, pretreatment laboratory data, and treatments, were compared between the infection-uncontrolled and -controlled groups. Disease stages were correlated with infection control and mortality. Results  The infection-uncontrolled rate and mortality rate were 38.5 and 23.1%, respectively. There were no significant differences in possible prognostic factors between the infection-uncontrolled and -controlled groups. HRCT-based stages significantly correlated with infection control and mortality. Conclusion  We proposed here the clinically useful diagnostic criteria and staging systems that can predict infection control and prognosis of otogenic SBO.

Skull base osteomyelitis in patients with head and neck cancer: Diagnosis, management, and outcomes in a case series of 23 patients

BACKGROUND

Skull base osteomyelitis (SBO) is an infection of the central cranial bones, most commonly resulting from contiguous spread of infection from adjacent head and neck structures. SBO is a well-recognized complication of treatment of head and neck cancer (HNC) that results in significant morbidity.

METHODS

We conducted a retrospective chart review of HNC patients diagnosed with SBO.

RESULTS

SBO was commonly diagnosed with nasal endoscopy showing mucosal breakdown between the naso/oropharynx and skull base and with characteristic changes on CT/MRI. Culture data were often polymicrobial, inclusive of naso/oropharyngeal flora, but half of the patients additionally had antibiotic-resistant or atypical pathogens. The mean duration of antimicrobial therapy was 117 +/- 94 days. Recurrent SBO was found in half of the patients, associated with Pseudomonas aeruginosa and with persistent defects in the mucosa abutting the skull base.

CONCLUSIONS

Diagnosis and management of SBO in HNC patients are challenging. Recommendations to aid in clinical care are proposed.

LEVEL OF EVIDENCE

4, case series.

Predicting Outcome in Skull Base Osteomyelitis: An Assessment of Demographic, Clinical, and Pathological Attributes

Objective  Skull base osteomyelitis (SBO) is an enigmatic clinical diagnosis which is difficult to decipher and is associated with poor outcomes. The study aims to examine the demographic and clinical characteristics of patients with SBO and its outcomes.

Materials and Methods  Medical records of 30 patients with diagnosis of SBO over past 5 years were assessed for demographic and clinical characteristics, type of SBO, radiological parameters, treatment received, procedure performed, microbiological profile, comorbidities, and complications including cranial nerve (CN) palsies. These factors were analyzed for prediction of outcome (death or survival).

Statistical Analysis  Microsoft Office Excel 2010 SAS 10.0 for Windows was used. Student's t -test for continuous variables (age, duration of symptoms, number of days of hospitalization, and treatment duration) and chi-square test for categorical variables (imaging findings, symptomatology, presence of comorbidities, surgical procedure, complications, and type of antibiotics) were utilized.

Results  We found SBO was the disease of elderly population (64.07 ± 6.13 years) with male predominance (83.3%) highly associated with uncontrolled diabetes status (93.3%). Headache (100%) and CN palsy (80%) were the most common neurological presenting complaints followed by stroke (17%) and encephalopathy (10%). Pathological and radiological correlation showed that fungal infection ( Aspergillus ) was associated with anterior SBO (10%), while bacteria ( Pseudomonas ) was cultured from posterior SBO (30%). Fifty per cent of patients were alive after 1 year out of which 33% had good functional outcome. The mortality rate was 33.3% in our cohort and multiple lower CN palsies ( p  = 0.04), suboptimal duration of medical treatment ( p  = 0.03), surgical intervention during clinical course ( p  = 0.02), and development of intracranial or extracranial complications ( p  = 0.03) were the predictors of mortality.

Conclusion  Early diagnosis including identification of pathogenic organisms and optimal duration of treatment are crucial factors for improved outcomes in SBO.

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.

Can imaging suggest the aetiology in skull base osteomyelitis? A systematic literature review

Purpose

To assess differentiating features between bacterial, Aspergillus, and Mucor skull base osteomyelitis (SBO) with regard to clinical presentation and imaging appearances.

Material and methods

A literature search was performed in April 2020 for studies on SBO with a minimum sample size of 10 patients. Studies that reported presenting symptoms, cross-sectional imaging findings, complications, and mortality were included in the analysis. The quality of included articles was tested using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. A data extraction form was used to retrieve relevant parameters from each of the articles.

Results

Thirteen articles were included in the final analysis. Diabetes mellitus was the most common predisposing factor (12.5-91.0%). Presenting complaints in all bacterial SBO studies were otogenic, while fungal SBO patients had nasal/ocular complaints. Rates of mortality and surgical intervention in the fungal group were 50-100% and 50%, respectively, as compared to the bacterial group – 7-87% and 10%, respectively. On imaging, the site of initial infection in bacterial SBO was the external auditory canal, while in fungal SBO it was the paranasal sinus. The incidence of orbital extension was < 5% in bacterial and 44-70% in fungal SBO, among which Mucor had rates of 65-70%. Bone erosion was less extensive in bacterial SBO, and the patterns differed. The highest incidence of vascular involvement and non-enhancing lesions (23-36%) was seen in Mucor. Aspergillus showed highest sino-cranial extension (52-55%) and homogenous bright enhancement.

Conclusions

Systematic analysis of the clinico-radiological parameters in each of the studies revealed differences in presentation, clinical course, extension, bone erosion, and enhancement.

MRI of Emergent Intracranial Infections and Their Complications

Acute intracranial infections of the central nervous system and skull base are uncommon but time sensitive diagnoses that may present to the emergency department. As symptoms are frequently nonspecific or lack typical features of an infectious process, a high index of suspicion is required to confidently make the diagnosis, and imaging may not only serve as the first clue to an intracranial infection, but is often necessary to completely characterize the disease process and exclude any confounding conditions. Although computed tomography is typically the initial imaging modality for many of these patients, magnetic resonance imaging offers greater sensitivity and specificity in diagnosing intracranial infections, characterizing the full extent of infection, and identifying potential complications. The aim of this article is to serve as a review of the typical and most important imaging manifestations of these infections that can be encountered in the emergent setting.

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.

Skull base osteomyelitis: Comprehensive analysis and a new clinicoradiological classification system

OBJECTIVE

Skull baseosteomyelitis (SBO) is a rare phenomenon that typically occurs in diabetic or immunocompromised patients, causing significant morbidity and mortality. This study aimed to analyze a single institution's treatment results in SBO patients and propose anew integrated clinicoradiological classification system.

METHODS

The medical records of 32 SBO patients that were treated at a tertiary care center between 2006 and 2017 were retrospectively reviewed. A scoring system based on anatomical involvement according to MRI was created. Subsequently, the scoring system was integrated with cranial nerve dysfunction status and a clinical grading system (CGS) was proposed.

RESULTS

Among the 32 patients, 78.1% were diabetic and 63% had cranial nerve dysfunction at presentation. Bone erosion based on CT was greater in the patients without regression (P = 0.046). The regression rate decreased from clinical grade (CG)1 to CG3 (P = 0.029). Duration of hospitalization increased as CG increased (P = 0.047). Surgery had no effect on regression status at the time of discharge (P = 0.41). The 1-year, 2-year, and 5-year overall survival rates were 82.2%, 70.8%, and 45.8%, respectively. CG was significantly correlated with overall survival but not with disease-specific survival (log-rank; P = 0.017, P = 0.362, respectively).

CONCLUSION

SBO continues to pose a challenge to clinicians, and causes significant morbidity and mortality. The proposed new classification system can be an option for grouping SBO patients according to clinical and radiological findings, helping clinicians estimate prognosis.

The challenging diagnosis and follow-up of skull base osteomyelitis in clinical practice

PURPOSE

The disease activity of skull base osteomyelitis can be challenging to assess by means of conventional imaging methods and renders monitoring of the disease difficult, especially in areas with restricted access to nuclear medicine imaging. Here, we provide clinically relevant data on the management of skull base osteomyelitis including assessment, treatment, and follow-up strategies with regards to the role of imaging.

METHOD

A chart review was performed including 30 patients treated for SBO from 1993 to 2015. Clinical findings, treatment procedures, and complication rates were assessed. Special attention was paid to imaging procedures.

RESULTS

The overall mortality rate was 36.7% and increased to 45% when cranial nerve palsies were present. An initial computed tomography (CT) scan was performed in all patients, MRI in 60% and nuclear imaging in 33%. CT scans failed to detect progression or regression in up to 80% after four to nine months. MRI examinations could reveal changes at a higher rate compared to CT. Nuclear medicine functional imaging was most likely to assess disease activity.

CONCLUSION

A combination of different imaging modalities is recommended for diagnosing SBO. For the follow-up, MRI is preferable to CT as changes can be detected more readily with MRI. If available, nuclear medicine imaging should guide the decision of treatment discontinuation.

Diagnosis of Skull Base Osteomyelitis

Skull base osteomyelitis (SBO) is an infection of the temporal, sphenoid, or occipital bone that can be a challenge to diagnose because of its nonspecific symptoms, long clinical course, and radiologic findings that mimic those of other entities. The authors review this unusual infection on the basis of six proven cases. The diagnosis of SBO should be made according to four points: a high index of clinical suspicion, radiologic evidence of infection, repeated biopsies that are negative for malignancy, and positive results of microbiologic tests. SBO typically manifests clinically in patients with diabetes and recurrent otitis externa; the infection usually extends inferiorly to the compact bone of the infratemporal fossa, affecting the lower cranial nerve foramina. Several image-based techniques should be used to diagnose SBO. CT is the best option for evaluating bone erosion and demineralization, MRI can help delineate the anatomic location and extent of disease, and nuclear imaging is useful for confirming bone infection with high sensitivity. However, the standard diagnostic procedure for SBO is for patients to undergo repeated biopsies to rule out malignancy, with histopathologic signs of infection and detection of microorganisms in the biopsied bone or soft tissue indicating SBO. The ability to diagnose SBO can be increased by identifying patients at risk, recognizing the most important causes and routes of infection, describing the main radiologic findings, and always considering the differential diagnosis. ^©RSNA, 2021.

Comparative study of reliability of inflammatory markers over 18-FDG-PET CT scan in monitoring skull base osteomyelitis

Introduction

The end point of treatment in skull base osteomyelitis is a matter of debate. A treatment based on symptoms alone is fraught with recurrence. There is a need to restrict imaging though more informative. The inflammatory markers like C-reactive protein and erythrocyte sedimentation rate used commonly need a detailed evaluation to optimize its utility.

Objectives

To compare the diagnostic accuracy of inflammatory markers with a hybrid PET scan in monitoring skull base osteomyelitis. The secondary objective was to obtain a cut-off value of these markers to decide upon antibiotic termination.

Methods

A prospective cohort study was conducted in a tertiary care center with fifty-one patients with skull base osteomyelitis meeting eligibility criteria. Patients diagnosed with skull base osteomyelitis were serially monitored with weekly markers and PET scan after the initiation of treatment. A hybrid scan was taken at 6–8 weeks of treatment and repeated if required. The follow-up period varied from 6 weeks to 15 months. The outcome measures studied were the values of markers and the metabolic activity of PET scan when the patient became asymptomatic and when disease-free.

Results

C-reactive protein and erythrocyte sedimentation rate had a statistically significant correlation to disease activity in PET tomography scan as a prognostic marker. Both showed good clinical correlation. A cut off value of ≤ 3.6 mg/L for C-reactive protein and ≤ 35 mm/hour for erythrocyte sedimentation rate were taken as normalized values.

Conclusion

A consistent normalized value of C-reactive protein and erythrocyte sedimentation rate for 8–12 weeks in an asymptomatic patient may be an indicator of disease control, though not cure. So, relying solely on markers alone for antibiotic termination may cause relapse. It may be used cautiously in a peripheral setting without access to more specific hybrid scans. In a tertiary care, follow-up scans may be done based on the titres, thereby limiting the radiation exposure.

Prediction of skull base osteomyelitis in necrotising otitis externa with diffusion-weighted imaging

OBJECTIVE

To predict skull base osteomyelitis in patients with necrotising otitis externa using diffusion-weighted imaging.

METHODS

A retrospective analysis was conducted of 25 necrotising otitis externa patients with skull base osteomyelitis (n = 10) or without skull base involvement (n = 14) who underwent a single-shot diffusion-weighted imaging of the skull base.

RESULTS

The respective mean apparent diffusion coefficient values of the skull base, as determined by two reviewers, were 0.851 ± 0.15 and 0.841 ± 0.14 ×10-3mm2/s for the skull base osteomyelitis patients, and 1.065 ± 0.19 and 1.045 ± 0.20 ×10-3mm2/s for the necrotising otitis externa patients without skull base involvement. The difference in apparent diffusion coefficients between the groups was significant, for both reviewers (p = 0.008 and 0.012). The optimal threshold apparent diffusion coefficient for predicting skull base osteomyelitis in necrotising otitis externa patients was 0.945 ×10-3mm2/s and 0.915 ×10-3mm2/s, with an area under the curve of 0.825 and 0.800, accuracy of 87.5 and 83.3 per cent, sensitivity of 85.7 and 90.0 per cent, and specificity of 90.0 and 78.6 per cent, for each reviewer respectively.

CONCLUSION

Apparent diffusion coefficient is a non-invasive imaging parameter useful for predicting skull base osteomyelitis in necrotising otitis externa patients.

Skull base osteomyelitis: clinical and radiologic analysis of a rare and multifaceted pathological entity

Skull base osteomyelitis (SBO) is a potentially life-threatening inflammation of cranial base bony structures of variable origin. Criteria for diagnosis and treatment are still controversial. Demographics, predisposing factors, symptoms, imaging, and clinical, laboratory, histological, and microbiological data of patients managed for SBO at the University Hospital of Brescia (ASST Spedali Civili) between 2002 and 2017 were retrospectively reviewed. Patients were included in different etiological groups. The topographic distribution of magnetic resonance (MR) abnormalities was recorded on a bi-dimensional model of skull base, on which three different patterns of inflammatory changes (edematous, solid, or necrotic) were reported. In patients with a history of radiotherapy, the spatial distribution of SBO was compared with irradiation fields. The association between variables and etiological groups was verified with appropriate statistical tests. A classification tree analysis was performed with the aim of inferring a clinical-radiological diagnostic algorithm for SBO. The study included 47 patients, divided into 5 etiological groups: otogenic (n = 5), radio-induced (n = 16), fungal (n = 14), immune-mediated (n = 6), and idiopathic (n = 6). At MR, five types of topographical distribution were identified (central symmetric, central asymmetric, orbital apex, sinonasal, maxillary). In patients with a history of radiotherapy, the probability to develop SBO was significantly increased in areas receiving the highest radiation dosage. The analysis of patients allowed for design of a classification tree for the diagnosis of SBO. The integration of clinical and radiologic information is an efficient strategy to categorize SBO and potentially guide its complex management.

Malignant Otitis Externa is Associated with Diabetes: A Population-Based Case-Control Study

Objective:

Despite studies reporting a possible association between malignant otitis externa (MOE) and diabetes, there are no large-scale population-based empirical studies. This nationwide, population-based case-control study explored the association of MOE occurrence with previously diagnosed diabetes.

Methods:

Data were retrieved from Taiwan’s National Health Insurance Research Database, 753 patients with MOE (cases) and 2 259 propensity score-matched patients without MOE (controls). Multiple logistic regressions were conducted to examine the association of MOE with previously diagnosed diabetes.

Results:

In total, 728 (24.2%) out of 3 012 sample patients had diabetes prior to the index date. Chi-square test revealed a significant difference in diabetes prevalence among cases and controls (54.8% vs 13.9%, p < 0.001). Simple logistic regression showed the odds ratio for prior diabetes among cases versus controls was 7.50 (95% CI, 6.22~9.03). The adjusted odds ratio of prior diabetes for cases versus controls was 10.07 (95% CI, 8.15~12.44) after adjusting for patient demographics and medical co-morbidities.

Conclusions:

This study found an association between MOE and diabetes. One clinical practice implication of our study is that when a patient with diabetes complains of otalgia or otorrhea, and physical examination shows swelling of the ear canal or granulation growth, physicians should consider the possibility of MOE.

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.

The routes of infection spread in central skull-base osteomyelitis and the diagnostic role of CT and MRI scans

Background

Central skull-base osteomyelitis (CSBO) represents a life-threatening complication of external ear canal infection. Computed tomography (CT) and magnetic resonance imaging (MRI) play key roles in assessment of CSBO progression.

Methods

Twelve patients with CSBO were included in a retrospective clinical study. In total, 62 scans (30 CTs and 32 MRIs) were performed to evaluate the extent of inflammatory changes. The scans were read independently by two radiologists specialised in imaging of the head and neck. The regions under the skull base were specified using the online Anatomy Atlas of the skull base. To clarify the timeline, the time period was divided into four parts, and inflammatory changes in the skull-base regions were tracked. Data were statistically analysed.

Results

In early stages of the disease, CT scan detects inflammatory changes closely related to the stylomastoid foramen and medially to the posterior belly of the digastric muscle, changes which have been proved to be crucial for the diagnosis of CSBO. Later the infection spreads to the contralateral side causing demineralisation of the bones.

Conclusion

Imaging methods play a crucial role not only in establishing the diagnosis, but also in anticipating the direction of infection spread underneath the skull base.

Severe Daily Headache as an Uncommon Manifestation of Widespread Skull Base Osteomyelitis

Temporal bone osteomyelitis has been recognized for decades as a complication of otitis externa, specifically in elderly patients with diabetes. A much less prevalent form is skull base osteomyelitis. We report a 70-year-old man with diabetes who presented to our outpatient clinic with severe chronic daily complaints of headache. The headache was located frontoparietally and kept him awake at night. Imaging (nonenhanced computed tomography [CT], magnetic resonance imaging, and positron emission tomography/CT) showed a hypermetabolic mass on the right side of the skull base, in the middle ear, and in the mastoid process, with invasion and partial destruction of the surrounding elements of the petrous bone, the occipital bone, and the sphenoid bone on the right, with extension by way of the clivus into the apex of the left petrous bone. Diagnostic puncture revealed Streptococcus pneumoniae. The final diagnosis was severe daily headache due to central skull base osteomyelitis. Our case emphasizes the need for proper clinical and radiological investigation keeping the diagnosis of skull base osteomyelitis in mind with patients with diabetes or otherwise immunocompromised status who present with chronic daily headache and otalgia.

Fungal Malignant Otitis Externa Involves a Cascade of Complications Culminating in Pseudoaneurysm of Internal Maxillary Artery: A Case Report

Patient: Male, 66

Final Diagnosis: Pseudoaneurysm of internal maxillary artery secondary to fungal malignant otitis externa

Symptoms: Epistaxis

Medication: —

Clinical Procedure: Functional endoscopic sinus surgery, endovascular embolization

Specialty: Infectious Diseases

Nocardial clival osteomyelitis secondary to sphenoid sinusitis: an atypical skull base infection

Clival osteomyelitis is a life-threatening complication of untreated malignant otitis externa or paranasal sinus infection. Although various pathogens have been implicated, to our knowledge, primary nocardial clival osteomyelitis has never been reported. We describe a 74-year-old woman who presented with headaches, abducens and hypoglossal nerve palsies, facial numbness, photophobia, and neck stiffness. Imaging revealed a heterogeneous mass within the sphenoid sinus with clival extension. The lesion was extirpated via a binostril endoscopic endonasal transsphenoidal approach. Histopathological and microbiological examination revealed a nocardial source. Clival osteomyelitis associated with sphenoid sinusitis should be included in the differential diagnosis of progressive skull base lesions in the setting of an underlying infection. Early recognition and intervention with antibiotics and surgical debridement is essential in the management of this rare entity.

A retrospective review of 14 cases of malignant otitis externa

Background

Malignant otitis externa is an inflammatory condition of the external ear which has the propensity to spread to the skull base. It can be a difficult entity to treat as clinical presentation varies and response to treatment differs between patients. We reviewed cases of malignant otitis externa in our setup to document the epidemiology and outcome of management.

Methods

This is a retrospective case review observational study from January 2013–December 2017. Fourteen patients diagnosed with malignant otitis externa in our tertiary referral centre were included in the study. Based on hospital protocol, empiric treatment was started. After discharge, the patients follow up visits to the hospital were also documented.

Results

Otalgia was the most common symptom. Edema and congestion of the external auditory canal were observed in most cases. Diabetes was present in all patients. Three cases had associated facial palsy, and one patient had involvement of 7th, 9th, 10th, 11th and 12^th cranial nerve. Two patients with facial palsy recovered. Pseudomonas aeuroginosa was the most common organism isolated (50%).

Conclusions

In our series, malignant otitis externa invariably presented with severe otalgia. Lower cranial palsies were also seen. Methods to evaluate complete eradication of disease should be centered on clinical symptoms and signs, but the measurement of erythrocyte sedimentation rate or radiological imaging may be used as a useful adjunct when there is uncertainty.

Clinical characteristics and complications of skull base osteomyelitis: A 12-year study in a teaching hospital in South India

Context:

Skull base osteomyelitis (SBO) is an uncommon disease with substantial morbidity and mortality.

Aims:

The aim of this study is to characterize clinical features, outcomes, and complications of SBO. We also looked at differences in clinical profile in otogenic and non-otogenic SBO.

Materials and Methods:

This is a single-center retrospective observational study. Patients aged more than 15 years of age with clinical and radiological diagnosis of SBO admitted in general medicine department in a teaching hospital in South India from March 2006 to February 2018 were recruited.

Results:

A total of 41 patients with SBO were identified and included. Mean age was 56.9 ± 10.7 years. In all, 90% of patients (37/41) had diabetes mellitus and 29% (12/41) had recent head/neck surgery. Only 19% (8/41) needed ICU care, and mortality was 21% (9/41). Most common symptom was headache seen in 73% (30/41) of patients. Majority, 61% (25/41), had otogenic infections. Otogenic infections were associated with longer duration of diabetes mellitus (mean = 11.5 vs. 5 years, P = 0.01), higher creatinine levels (mean = 1.66 vs. 0.9 mg/dL, P = 0.014, odds ratio [OR] = 3.8), and higher incidence of cranial nerve palsy (92% vs. 56%; OR = 8.9) compared to non-otogenic SBO. Cranial nerve palsy (78%), meningitis (63%), and cerebral venous thrombosis (43%) were frequent complications of SBO in this study. The causative organisms for SBO in our cohort was bacterial in 60% (15/25) and fungal in 40% (10/25) of the patients. Surgical debridement for source control was done in 54% of patients (22/41) and was associated with survival at discharge (P = 0.001).

Conclusions:

Bacterial infections are the most common cause of SBO. Otogenic SBO is associated with longer duration of diabetes mellitus and higher incidence of cranial nerve palsy. Therapeutic surgical debridement plays an important role in treatment of SBO and is associated with improved survival.

Skull base osteomyelitis secondary to Scedosporium apiospermum infection

Scedosporium apiospermum is a common environmental mold which is increasingly reported in the literature as a cause of infection, particularly in the immunocompromised patient population. We present a case of malignant otitis externa due to S apiospermum, complicated by spread of infection causing skull base osteomyelitis, internal carotid artery vasculitis and subsequent stroke. Despite the multiple complications encountered, prompt diagnosis and initiation of appropriate antifungal treatment resulted in patient survival. Multiple imaging modalities were used to aid the establishment of the diagnosis in this complex case and highlight the radiological findings associated with skull base osteomyelitis and its possible complications.

99mTc-HMPAO-leukocyte scintigraphy for diagnosis and therapy monitoring of skull base osteomyelitis

Objective

Skull base osteomyelitis (SBO) is a rare but life‐threatening disease observed in elderly diabetic patients, with high risk of recurrence and difficult therapeutic management. The diagnosis is ascertained from a set of clinical, biological, and imaging findings. CT and MRI allow initial diagnosis, but are not accurate to affirm healing at the end of therapy. 99mTc‐HMPAO‐Leucocyte Scintigraphy (LS) is highly sensitive and specific for the detection of infection. The aim of this study was to evaluate LS i) for initial diagnosis, and ii) to confirm healing at the end of antibiotherapy in SBO.

Study design

We retrospectively reviewed from November 2011 to September 2015 all patients with confirmed SBO who underwent LS twice, at diagnosis and at the end of antibiotic therapy in our nuclear medicine department (n = 27).

Methods

Clinical, biological, CT, LS, and follow‐up data were recorded in all patients. LS images (planar and tomographic performed 4 hours and 24 hours after intravenous injection of autologous Tc‐99m‐HMPAO‐leucocytes) were visually assessed and quantified.

Results

At initial diagnosis, 25 of 27 patients had a positive LS. At the end of antibiotic therapy (3 ± 1 months duration), 26 of 27 patients had a negative LS. During subsequent follow‐up (= or >6 months), the disease recurred in four patients including three with a negative postantibiotherapy LS scan.

Conclusion

In this retrospective study, LS was powerful for initial diagnostic of SBO and for healing assessment at the end of antibiotic therapy. We conclude it is a useful technique for therapeutic monitoring of SBO.

Level of Evidence

4

A Treatment Protocol for Management of Bacterial and Fungal Malignant External Otitis: A Large Cohort in Tehran, Iran

AIMS

High rates of negative microbiologic test results highlight the potential role of empiric antimicrobial agents in management of malignant otitis externa (MOE). This study investigates the clinical presentation, laboratory findings, and response to empiric treatment in a large group of patients admitted to a tertiary academic hospital in Tehran, Iran.

METHODS AND MATERIALS

We recruited 224 patients diagnosed with MOE in a prospective observation from 2009 through 2015. All patients received a 2-agent antibacterial regimen at baseline (phase I). Patients with no improvement within 10 days and/or nonresponders to a second course of antibacterials were switched to antifungals (phase II). Response to treatment was observed and documented in both groups.

RESULTS

All patients had physical symptoms for more than 12 weeks before admission. In total, 127 patients responded well to antibacterials. Eighty-seven out of 97 patients who were switched to antifungals had complete response to treatment; patients in the latter group had significantly higher A1C levels at baseline.

CONCLUSION

Our findings provide evidence to develop clinical guidelines that accelerate diagnosis and treatment of MOE to improve patient outcomes.

Clival Osteomyelitis Presenting as a Skull Base Mass

Central skull base osteomyelitis is a rare, but potentially life-threatening disease entity often lacking otologic symptoms or external auditory canal pathology. We present a case of a man in his 70s who had developed cranial nerve deficits with radiographic evidence that was consistent with a tumor due to this uncommon entity. The radiologic findings and our experience are discussed to increase awareness in the otolaryngology community.

Severe skull base osteomyelitis caused by Pseudomonas aeruginosa with successful outcome after prolonged outpatient therapy with continuous infusion of ceftazidime and oral ciprofloxacin: a case report

Background

Skull base osteomyelitis is an uncommon disease that usually complicates a malignant external otitis with temporal bone involvement. It affects predominantly diabetic and immunocompromised males and has a high mortality rate. Pseudomonas aeruginosa is the most common causative organism. Currently, there is no consensus about the best therapeutic option. Here we describe a case of severe skull base osteomyelitis caused by Pseudomonas aeruginosa with progressive palsy of cranial nerves that was successfully managed with prolonged outpatient continuous infusion of ceftazidime plus oral ciprofloxacin.

Case presentation

A 69-year-old Caucasian man presented with dysphagia, headache, and weight loss. He complained of left earache and purulent otorrhea. Over the following weeks he developed progressive palsy of IX, X, VI, and XII cranial nerves and papilledema. A petrous bone computed tomography scan showed a mass in the left jugular foramen with a strong lytic component that expanded to the cavum. A biopsy was then performed and microbiological cultures grew Pseudomonas aeruginosa. After 6 weeks of parenteral antibiotic treatment, our patient was discharged and treatment was continued with a domiciliary continuous infusion of a beta-lactam through a peripherally inserted central catheter, along with an oral fluoroquinolone for 10 months. Both radiological and clinical responses were excellent.

Conclusions

Skull base osteomyelitis is a life-threating condition; clinical suspicion and correct microbiological identification are key to achieve an accurate and timely diagnosis. Due to the poor outcome of Pseudomonas aeruginosa skull base osteomyelitis, prolonged outpatient parenteral antibiotic therapy administered by continuous infusion could be a valuable option for these patients.

A Case of Skull Base Osteomyelitis with Multiple Cerebral Infarction

Skull base osteomyelitis is classically documented as an extension of malignant otitis externa. Initial presentation commonly includes aural symptoms and cranial nerve dysfunctions. Here we present a case that emerged with multiple infarctions in the right cerebrum. A male in his 70s with diabetes mellitus and chronic renal failure presented with left hemiparesis. Imaging studies showed that blood flow in the carotid artery remained at the day of onset but was totally occluded 7 days later. However, collateral blood supply prevented severe infarction. These findings suggest that artery-to-artery embolization from the petrous and/or cavernous portion of the carotid artery caused the multiple infarctions observed on initial presentation. Osteomyelitis of the central skull base was diagnosed on the basis of the following findings taken together: laboratory results showing high levels of inflammation, presence of Pseudomonas aeruginosa in the otorrhea and blood culture, multiple cranial nerve palsies that appeared later, the bony erosion observed on CT, and the mass lesion on MRI. Osteomyelitis was treated successfully by long-term antibiotic therapy; however, the patient experienced cefepime-induced neurotoxicity during therapy. The potential involvement of the internal carotid artery in this rare and life-threatening disease is of particular interest in this case.

Scedosporium apiospermum as a rare cause of central skull base osteomyelitis

We report a case of Scedosporium apiospermum mold causing ear infection, central skull base osteomyelitis and finally, occlusion of carotid artery in a 48-year-old diabetic man. The exact diagnosis was established and the severity of the disease understood several months after the onset of symptoms. Despite of appropriate antifungal therapy, and repeated surgical and otological procedures, the infection progressed to fatal cerebral infarction.

Skull base osteomyelitis missed in mastoidectomy for cholesteatoma

Conclusions A high suspicion of skull base involvement should be warranted, even if radiological findings are not atypical, in cases of chronic otitis media (COM) with cholesteatoma. Objective To investigate some clues indicating the development of skull base osteomyelitis (SBO) in patients who received mastoidectomy, through reviewing pre-operative temporal bone computed tomography (TBCT). Method Retrospective review of patients with SBO after mastoidectomy for COM. A total of five patients with SBO after mastoidectomy with available pre-operative TBCTs were enrolled in this study. Results All patients were diagnosed as COM with cholesteatoma and open cavity mastoidectomy was performed. After surgery, SBO were occurred. The recovery in these five patients was complicated by lower cranial nerve palsy, and one patient had a stroke due to lateral thrombophlebitis. Through re-interpretation of pre-operative TBCT, the bony destruction around the skull base missed at the initial diagnosis was observed in all cases.