Skull base osteomyelitis secondary to malignant otitis externa

Diffusion-Weighted Imaging Does Not Differentiate Between Bacterial and Fungal Skull Base Osteomyelitis

OBJECTIVE

Apparent diffusion coefficient (ADC) value helps in differentiating infections from neoplasms on magnetic resonance imaging (MRI). We investigate the diffusion-weighted images in skull base osteomyelitis (SBO) to evaluate if ADC values can differentiate fungal and bacterial SBO and to analyse the microbiology of all SBO patients.

DESIGN

Retrospective observational study.

SETTING

Quaternary care referral centre.

PARTICIPANTS

A retrospective review of 142 patients diagnosed and treated for SBO patients from January 2010 to May 2023 was done.

MAIN OUTCOME MEASURE

Chi-square or Fisher's exact test was used to compare ADC values of bacterial and fungal SBO.

RESULTS

The most common pathogens isolated were Pseudomonas (42.2%), Aspergillus (30.98%), and S. aureus (23.94%). The average ADC value of affected soft tissues among patients was 1.13 ± 0.26 × 10-3 mm2/s compared to the average ADC value of normal soft tissue, 1.34 ± 0.31 × 10-3 mm2/s. There was no statistical significance when comparing the average ADC values of bacterial and fungal SBO patients (p value = 0.142).

CONCLUSION

This study suggests that though infection due to Pseudomonas was the commonest, it was detected only in 42.2% of patients. More than half of the cases had organisms other than Pseudomonas, demanding the clinician to obtain deeper biopsies early in the course of the disease for microbiological analysis. DWI does not help differentiate bacterial and fungal SBO, again emphasising the need for deeper tissue biopsies in all these patients to assist in the early identification of the pathogen.

Skull Base Osteomyelitis Due to Staphylococcus epidermidis in the Absence of Indwelling Medical Devices Presenting With Bilateral Internal Carotid Artery Thrombosis

Skull base osteomyelitis (SBO) is a severe and uncommon infection that typically affects the skull base and may arise from undiagnosed otogenic or sinonasal infection. This case describes a rare presentation of SBO, accompanied by thrombosis of the bilateral internal carotid artery with neurological deficits in a resource-limited environment, illustrating diagnostic and management dilemmas. A male patient aged 40 years with poorly controlled type 2 diabetes presented with sudden onset loss of consciousness and worsening right-sided weakness. MRI studies revealed SBO with cerebral involvement with thrombosis in major cerebral arteries and multiple brain infarcts. After receiving broad-spectrum antibiotics and supportive care shortly after admission, the patient developed septic shock and died two days after admission. The fast course of the disease in this case shows how severe SBO and its complications may be, calling for early diagnosis and intensive management of SBO, especially in diabetic patients. The fact that Staphylococcus epidermidis was established as a causative agent of disease in the absence of artificial heart valves or joints, it is becoming clear that there is a need to increase awareness of such rare pathogens, and probably new strategies for handling such infections should be developed. Additional research is required to elucidate the precise role of the pathogen and refine treatment approaches, especially for low-resource healthcare systems.

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.

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.

Central Skull Base Osteomyelitis: A Case Series from a Tertiary Care Center Over 5 Years

OBJECTIVE

Skull base osteomyelitis may rarely present in the sphenoid bone or clivus without an otologic source. This is referred to as central skull base osteomyelitis (CSBO). Knowledge regarding CSBO is limited to case reports and small case series. Here we present a case series to further describe typical patient characteristics, clinical presentation, and clinical course associated with this rare infection.

METHODS

All patients treated at a single academic tertiary care institution for CSBO from 2016 through 2020 were identified. Inclusion criteria included culture proven CSBO without an otologic or iatrogenic source. Data were extracted via patient chart review and qualitatively analyzed.

RESULTS

Seven patients were identified with CSBO, 5 male and 2 female. Age ranged from 63 to 87 (average 76). Risk factors included advanced age, diabetes, and history of radiation. The most common presenting symptom was headache (6), followed by otalgia (4). Two patients presented with cranial neuropathies. Diagnosis was facilitated by history and exam (including flexible laryngoscope exam), imaging (MRI), and labs (ESR). All patients received endoscopic biopsy and culture (most commonly polymicrobial, with diverse species). Treatment involved IV antibiotics, with a limited role for surgery. All patients survived and achieved resolution of infection.

CONCLUSIONS

CSBO remains a diagnostic challenge due to its rarity and vague presenting symptoms that overlap with presentation of sinonasal malignancies. A high index of suspicion is required by the evaluating provider to ensure a timely diagnosis with early treatment in order to limit the significant morbidity which can be associated with this infection.

LEVEL OF EVIDENCE

4.

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.

Clinical and Current Microbiological Profile with Changing Antibiotic Sensitivity in Malignant Otitis Externa

Malignant otitis externa (MOE) is a rare and fatal condition affecting temporal bone. It is also known as skull base osteomyelitis and is a rapidly progressive condition. This retrospective study evaluates the clinical, haematological, microbiological profile and management of malignant otitis externa in a tertiary care hospital and literature review. A retrospective review of 79 patients diagnosed with Malignant Otitis Externa from January 2015 to June 2021 was analyzed. History and Clinical findings, Imaging, Bacteriology, Random blood sugar on admission, Erythrocyte Sedimentation rate, HbA1C level, Biopsy of the granulation tissue from Externa auditory canal, cranial nerve involvement, duration of hospital stay, and treatment outcomes were analyzed. Out of 79 patients, otorrhea, otalgia, EAC oedema, and granulation were the most common findings. Facial nerve paralysis was found in 20 patients (25.3%) and multiple cranial nerve paralysis in 5 patients (6.3%). Uncontrolled diabetes mellitus and older age have increased duration of hospital stay, while cranial nerve paralysis did not affect this duration. Six different microorganisms were isolated. Pseudomonas aeruginosa was the most common organism cultured. Ciprofloxacin resistance was detected in 79% of cases. Amikacin, Cefaperazone-Sulbactam, and Piperacillin were the most sensitive antibiotics for gram negative organisms in our study. This study reviews the current microbiological profile and shows the need for higher-end antibiotics to treat MOE in present times. Early diagnosis, aggressive control of diabetes mellitus, and long duration culture-sensitive antibiotic therapy with regular monitoring are essential to reducing morbidity and mortality due to MOE.

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

Skull base osteomyelitis mimicking skull base tumor in immunocompetent pediatric patient: case report

Central skull base osteomyelitis (CSBO) is a rare complication of infection in pediatric patients, especially when there are no comorbidities like immunosuppression or metabolic illness. The diagnosis of CSBO is a challenge in children, and imaging findings can mimic skull base tumor. We describe the clinical history and image diagnosis of a case in a 6-year-old girl with no relevant history who presented an extensive skull base lesion. She underwent tumor resection surgery. The intraoperative finding confirmed clivus osteomyelitis, and the histopathological studies discarded malignancy. After diagnosis, the patient completed 6-week antibiotic treatment with adequate evolution. In conclusion, CSBO should be considered within the differential diagnoses due to the fact that it can mimic skull base lesions and it may present without relevant history.

The association between radiological spreading pattern and clinical outcomes in necrotizing external otitis

Objectives

Methods

Results

Conclusion

Level of evidence

Spectrum of mycobacterial pathogens responsible for head and neck tuberculosis-like presentation

Tuberculosis (TB) of the head and neck can be contained in the lymph nodes, larynx, oropharynx, salivary glands, nose and paranasal sinuses, ear, skin and skull. Head and neck TB presentations are varied in nature and thus difficult to diagnose. The clinical features, radiological findings, microbiological diagnostic modalities, surgical and medical management and outcomes of nine cases of head and neck TB are discussed in detail here, together with a thorough review of the literature. Patients presented with atypical symptoms such as discharging sinus, ear lobule swelling, otitis media, vision loss and facial weakness, long refractory otorrhoea and granulation tissue in the ear canal. We diagnosed tubercular skull base osteomyelitis (one case) and laryngeal tuberculosis (two cases), mastoid tuberculosis (one case) and non-tubercular mycobacterial infection involving the temporal bone (two cases), sino-nasal region (one case), maxilla (one cases) and ear lobule (one case) over a period of 8 months. All patients were managed successfully with a combination of surgery and a well-planned treatment regimen for non-tuberculous mycobacteria (NTM) or anti-tubercular drugs for TB. All had successful outcomes except one patient with tubercular skull base osteomyelitis who expired before the initiation of anti-tubercular therapy (ATT). High clinical suspicion followed by thorough diagnostic work-up for both TB and NTM would enable early diagnosis and complete treatment.

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.

Current management of skull base osteomyelitis

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

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

BACKGROUND AND PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

A Case Series of Malignant Otitis Externa Mimicking Malignancy

Malignant otitis externa is an inflammation of the external auditory canal with preceding osteomyelitis of the temporal bone and the adjacent structures that could be potentially lethal. Malignant otitis externa may present with cranial nerve involvements and massive spread of disease mimicking nasopharyngeal carcinoma or any other malignancies on imaging. Two elderly patients who presented with severe otalgia and significant facial nerve palsy and lower cranial nerve palsies showing extensive spread of disease are reported in this case series. They both had resolution of disease after a prolonged course of antibiotics and cortical mastoidectomy for disease clearance in one of them.

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.

Skull Base Osteomyelitis With Facial and Trigeminal Nerve Involvement Secondary to Otitis Media

Skull base osteomyelitis (SBO) is a rare condition that is associated with high morbidity rates. It is most commonly caused by an infection in the external part of the ear that eventually spreads to the skull base and related structures. To our knowledge, reports in the literature concerning atypical causes of SBO (e.g., otitis media) have been scarce. In this report, we present a rare case of an elderly diabetic patient who presented with unilateral SBO originating from an infection in the middle ear. This patient also had ipsilateral facial weakness and trismus, indicating a spread of the infection to the facial and trigeminal cranial nerves.

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.

From Uncommon Infection to Multi-Cranial Palsy: Malignant External Otitis Insights

Purpose:

The progression of the otitic infectious process toward diseases of particular severity is often unpredictable, just as it is challenging to manage the patient over time, even after the apparent resolution of the disease. We aim to define a radiological reading key that allows us to correctly and promptly treat the disease, avoiding the possible severe complications.

Methods:

We conducted a retrospective study of 13 cases of basal cranial osteomyelitis (SBO) due to malignant external otitis, by the ENT Department of the University of Catania. Through a standardized approach and following the latest guidelines, we have evaluated all patients performing a standardized and personalized radiological protocol according to the stage of the patient’s pathology and modulating the treatment consequently.

Results:

Clinical signs have been observed such as otorrhea (100%), otalgia in 13/13 patients (100%), granulations in external auditory canal (100%), preauricular cellulitis in 9/13 patients (69%) headache 6/13 cases (46%), dysphonia 4/13 cases (31%). HRCT of the temporal bone proved useful in identifying even minimal bone lesions in 13/13 (100%) while improving MRI in vascular and nervous involvement, although in 1/13 patient with nerve palsy clinical symptomatology preceded radiological evidence. The 99mTc 3-phase planar bone scintigraphy was positive for SBO in 9/13 cases (69%) during the initial phase and, in 100% of the cases in images delayed to 2-3 hours. Subsequent checks up to 1 year, using the Ga 67 scintigraphy, excluded the presence of recurrences in 100% of patients.

Conclusion:

The osteomyelitis of the base of the skull is a severe complication of malignant external otitis, often not always easily diagnosed. Recurrence can occur up to 1 year after stopping therapy. Imaging techniques such as Tc and MRI are relevant for the initial diagnostic approach and the staging of the pathology and its complications. Nuclear medicine imaging plays a fundamental role in the evaluation of related osteoblastic activity, especially in the remission phase of the disease.

Facial nerve paralysis in malignant otitis externa: comparison of the clinical and paraclinical findings

BACKGROUND

Malignant otitis externa is an uncommon but critical challenging disease with some degree of cranial nerve involvement.

AIM/OBJECTIVE

to examine the factors leading to facial paralysis in these patients and clarify indications for aggressive treatment in the group most at risk.

MATERIAL AND METHODS

In a case-control study, demographic, clinical, laboratory, audiometric, imaging, and treatment characteristics of 139 patients in groups with and without facial paralysis were analysed.

RESULTS

45 patients (32.4%) had facial paralysis. Compared to patients without facial nerve involvement, patients with facial palsy had a higher rate of inflammatory markers (mean erythrocyte sedimentation rate on admission [67.71 vs 51.16 mm/h], and the average of total ESR [64.27 vs 54.46 mm/h], as well as the mean C-reactive protein [38.96 vs 27.53 mg/L]). Also, the involvement of the facial canal (p < .01) and nasopharyngeal space (p < .05) were related to the incidence of facial paralysis.

CONCLUSION

Nasopharyngeal extension of the inflammation and facial nerve canal erosion might be useful as predictors of facial nerve dysfunction. The elevated erythrocyte sedimentation rate is correlated with the increased risk of facial paralysis, and aggressive medical management is more crucial.

SIGNIFICANCE

Improvement in predicting the outcome of patients with malignant otitis externa.

Central skull base osteomyelitis secondary to invasive aspergillus sphenoid sinusitis presenting with isolated 12th nerve palsy

Skull base osteomyelitis is a potentially life-threatening infection, usually seen in elderly immunocompromised patients secondary to malignant otitis externa (MOE) caused by Pseudomonas. Central or atypical skull base osteomyelitis often poses a diagnostic challenge as they present as head-ache with or without cranial nerve palsy often without any obvious source of infection. Although the incidence of fungal skull base osteomyelitis is increasing central skull base osteomyelitis due to invasive fungal sinusitis presenting with isolated hypoglossal nerve palsy has not been reported in the literature, to our knowledge. We report a case of a 59-year-old diabetic patient on regular treatment including steroid for acetylcholine receptor binding antibody positive myasthenia gravis with thymoma who presented with persistent head-ache and on evaluation, was found to have 12th cranial nerve palsy on the right side. She was diagnosed to have invasive fungal sphenoid sinusitis and central skull base osteomyelitis involving the clivus and was successfully treated with endoscopic transnasal transsphenoidal debridement followed by antifungal therapy.

Central skull base osteomyelitis manifesting with a preclival mass and internal carotid artery mycotic aneurysm

Central skull base osteomyelitis is a rare entity that can demonstrate confounding radiologic, clinical, and laboratory data leading to a delay in diagnosis. The morbidity and mortality for skull base osteomyelitis are both high, thus a rapid diagnosis is required for appropriate treatment. In this case report, we discuss a 68-year-old male who presented with acute left facial nerve paralysis in the setting of chronic headache and left mucoid middle ear effusion. Radiologic evaluation revealed abnormal hypointense marrow of the central skull base on T1 weighted magnetic resonance imaging, preclival mass-like tissue, and short segment luminal narrowing of the left cervical ICA with mycotic aneurysm formation.

Extensive workup via a multidisciplinary approach, including neurology, otolaryngology, neurosurgery and radiology led to a diagnosis of central skull base osteomyelitis. A familiarity of this disease process is important for the radiologist in order to facilitate appropriate patient referral and treatment. This case emphasizes the importance of considering this diagnosis in the setting of headache, cranial neuropathy, and abnormal skull base imaging with adjacent preclival soft tissue mass.

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.

Imaging the facial nerve: A contemporary review of anatomy and pathology

PURPOSE

The facial nerve is the seventh paired cranial nerve which anatomically can be divided into six distinct segments. There are a wide range of pathologies that may occur along each segment of the nerve. The aim of this pictorial review is to untangle the complex appearances of the facial nerve, both in its normal anatomical course and when affected by pathology.

METHOD

This review takes an evidence-based segmental approach to the evaluation of the facial nerve in terms of its anatomy and clinical features of common pathologies affecting specific segments of the nerve. The typical multimodal radiological findings of common facial nerve pathologies are included in the review using imaging from select pathologically confirmed cases.

RESULTS

A wide range of pathologies ranging from congenital abnormalities to inflammatory, infective and neoplastic processes can affect the facial nerve. As select segments of the nerve are better evaluated on certain imaging modalities a clear understanding of the anatomy and clinical features associated with specific facial nerve pathologies enables the radiologist to tailor the imaging test to best answer the clinical question.

CONCLUSIONS

This review provides a segmental clinical-radiological approach to imaging the facial nerve. In addition, recent developments in facial nerve imaging that may come into mainstream use in the near future are touched upon.

Thirty-Day Readmission and Prolonged Length of Stay in Malignant Otitis Externa

OBJECTIVES

To determine independent risk factors for 30-day readmission, prolonged length of stay (PLOS), and discharge to a rehabilitation facility for those with malignant otitis externa.

METHODS

Retrospective cohort study of patients hospitalized with malignant otitis externa (International Classification of Diseases, 9th edition, code 380.14) in the Nationwide Readmissions Database (2013-2014). Overall and disease-specific complication and mortality data were analyzed using chi-squared and multivariate analysis.

RESULTS

There were 1267 cases of malignant otitis externa extracted. A PLOS of ≥8 days (90th percentile) was found in 14.2% (n = 180) of patients, and 13.7% (n = 174) were discharged to a facility. Patients were readmitted within 30 days at a rate of 12.5% (n = 159). The overall rates of uncomplicated and complicated diabetes were found to be 42.1% and 17.8%, respectively. Factors independently associated with PLOS included undergoing a surgical procedure (odds ratio [OR] 2.08, P < .001), and having central nervous system complications (OR 3.21, P < .001). Independent risk factors for disposition to a facility included nutritional deficiency (OR 1.91, P = .029), PLOS (OR 4.61, P < .001), and age 65-79 years (OR 6.57, P = .001). Readmission was independently linked to PLOS (OR 3.14, P < .001). Diabetes was not an independent risk factor for any outcome.

CONCLUSIONS

Thirty-day readmission, PLOS, and ultimate discharge to a rehabilitation facility were common and closely intertwined. Despite the classic association between diabetes and malignant otitis externa, diabetes was not an independent risk factor for any of our outcomes.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:2220-2228, 2020.

Skull base osteomyelitis: factors implicating clinical outcome

Skull base osteomyelitis is a serious disease with a high risk of complications including neuroinfection. Typically, the inflammation of the skull base results from infection from neighboring tissues. In case of malignant otitis externa, inflammation disseminates from the external auditory canal. In this study, we present our experience with seven patients diagnosed with skull base osteomyelitis that began with otitis externa and have been treated in our department for the last 10 years. Department Patient Database was searched for the diagnosis skull base osteomyelitis. The search covered the last 10 years. The search revealed seven patients who met the above-described criteria. Medical records of those patients were carefully analyzed including age, gender, symptoms and signs, diagnostics details, treatment, performed procedures, number of hospitalization days, comorbid diseases, and complications including any cranial nerve palsy. Detailed analysis of medical records of patients included in this study showed that skull base osteomyelitis presents a challenge for diagnosis and treatment. Treatment strategy requires prolonged aggressive intravenous antibiotic therapy, and in some cases combined with surgical intervention. Cranial nerve paresis indicates progression of the disease and is associated with longer hospital stay. Similar relationship is observed in patients with skull base osteomyelitis that required surgery. Diabetes in patient’s medical history may complicate the healing process. Diabetes, neural involvement, and surgery may overlap each other resulting in longer hospital stay. Cranial nerve paresis may not resolve completely and some neural deficits become persistent.

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.

Imaging of Nontraumatic Temporal Bone Emergencies

This section aims to cover the non-traumatic pathologies affecting the temporal bone including external auditory canal, middle ear and inner ear which usually need emergent clinical attention. Many of the conditions in this section are secondary to infections in different clinical settings with resultant complications which may leave temporary or permanent sequelae if not suspected, timely diagnosed or treated.

Efficacy of HRCT Imaging vs SPECT/CT Scans in the Staging of Malignant External Otitis

OBJECTIVE

The prognosis of patients with malignant external otitis (MEO) depends on the extent of the inflammatory changes in the temporal bone and skull base. The efficacy of high-resolution computed tomography (HRCT) imaging in accurately assessing the extent of disease is compared with that of single-photon emission computed tomography/computed tomography (SPECT/CT) scan.

STUDY DESIGN

A clinical chart review was conducted with medical records and radiologic images.

SETTING

Tertiary care medical college hospital.

SUBJECTS AND METHODS

This study involved patients with clinically diagnosed MEO who underwent both modalities of imaging of the skull base. Staging of the disease extent was compared between the imaging systems among patients. Symptom control and survival rates were analyzed with respect to the SPECT/CT staging of MEO.

RESULTS

Out of 28 patients included in this study, 72% had SPECT/CT scans showing higher staging than the HRCT imaging. Four patients had mild uptake (stage 1), and 15 had disease confined to the mastoid/temporal bone, not reaching midline (stage 2). All patients in stages 1 and 2 were surviving with good symptom control. Five patients with petrous involvement reaching midline (stage 3) had persistent symptoms, and all 4 cases with SPECT/CT showing sphenoid involvement and crossing midline (stage 4) died within a year of diagnosis.

CONCLUSIONS

SPECT/CT scan is more sensitive than HRCT imaging in detecting the extent of disease and is a better prognosticator for patients with MEO.

Malignant otitis externa, an increasing burden in the twenty-first century: review of cases in a UK teaching hospital, with a proposed algorithm for diagnosis and management

Background

Malignant otitis externa is a potentially fatal infection of the skull base. With an ageing population and increasing prevalence of diabetes, the incidence of malignant otitis externa in the British population is rising. To date, there remain no accepted diagnostic criteria, few prognostic indicators and no consensus treatment pathways.

Method

A prospective case series was conducted at a tertiary referral teaching hospital.

Results

A cohort of susceptible individuals predominates (elderly, male, with immunosuppression and diabetes), with 25 per cent reporting a preceding incident. Otorrhoea, otalgia and canal granulation were the commonest presenting features, alongside positive pseudomonas cultures. No clear markers for predicating disease severity were isolated; however, a high initial haemoglobin A1c level demonstrated a significant moderately positive correlation with length of treatment.

Conclusion

A treatment pathway designed to provide a standardised approach to investigation and treatment is proposed, which aims to increase earlier diagnosis, streamline care and facilitate the development of best practice.

Additive value of 99mTechnetium methylene diphosphonate hybrid single-photon emission computed tomography/computed tomography in the diagnosis of skull base osteomyelitis in otitis externa patients compared to planar bone scintigraphy

The aim of this study was to evaluate the additive value of ^99mtechnetium methylene diphosphonate (^99mTc-MDP) hybrid single-photon emission computed tomography/computed tomography (SPECT-CT) in the diagnosis of skull base osteomyelitis (SBO) compared to planar bone scintigraphy (PBS). This was a single institution; prospective study included 23 patients with otitis externa, clinically suspected of SBO, all of them were diabetic. Three-phase bone scintigraphy and SPECT/CT were performed to all patients. The imaging modalities which had the most equivocal results were PBS (9/23) followed by SPECT (3/23). No equivocal results were detected with CT or SPECT-CT. SPECT-CT had the highest sensitivity (100%) and highest accuracy (95.7%) in diagnosis of SBO, whereas, PBS showed the lowest sensitivity (50%) and lowest accuracy (52.2%). In this study, SPECT-CT considered the best modality for accurate localization of the site of SBO involvement, followed by CT. SPECT and planar BS were less accurate in this consideration. When comparing the sensitivity of planar BS, CT, SPECT and SPECT/CT, statistical significance difference was detected between planar BS and SPECT (P = 0.057), planar BS and SPECT/CT (P = 0.001), and between CT and SPECT/CT (P = 0.031). No statistically significant difference was detected between SPECT and SPECT/CT (P = 0.250), CT and planar BS (P = 0.125), and between CT and SPECT (P = 0.508) In conclusion, ⁹⁹Tc-MDP SPECT/CT has high sensitivity in the diagnosis of SBO and also provide accurate localization of the site of SBO.

The significance of tissue biopsy for fungi in necrotizing otitis externa

INTRODUCTION

The conventional treatment for necrotizing otitis externa (NOE) is prolonged anti-pseudomonas therapy, with surgical treatment in non-responsive patients. The aim of the present study is to describe the course of management of patients with non-responsive NOE undergoing hyperbaric oxygen therapy (HBOT), and to investigate the importance of tissue biopsy for fungi in this group of patients.

MATERIALS AND METHODS

A retrospective study conducted between January 2010 and December 2013 at an Otolaryngology Head and Neck Surgery Department. Included were all 52 patients with NOE referred to our Medical Centre for further treatment including HBOT.

RESULTS

Fifty-two consecutive patients, 29 men and 23 women, with a mean age of 70.6 years, were included in our study. Twenty seven (51.9%) underwent surgical debridement. No significant difference was found between the group having surgical intervention, and those who did not, with regard to sex, age, comorbidities, cranial nerve involvement or laboratory results. However, those who had surgical intervention had a statistically significant higher rate of fungal infection (P = 0.049). After completing 7 weeks of HBOT, a significantly lower WBC count was observed in the fungus-infected group (7000 vs 7.800, P = 0.03), and a tendency towards lower CRP levels in the fungus-infected group (16 vs 58, P = 0.087).

CONCLUSION

Patients with NOE should have a comprehensive surgical intervention when delayed healing is observed, because proper fungal culturing might change the course of treatment and improve prognosis.

LEVEL OF EVIDENCE

4.

Normal Variant Occipital Pneumatization

OBJECTIVE

Evaluate prevalence and pattern of occipital pneumatization (OP).

PATIENTS

Individuals with imaging evidence of OP on computed tomography (CT).

INTERVENTION(S)

High resolution CT scans of the temporal bone.

MAIN OUTCOME MEASURE

The prevalence and pattern of OP on 1000 CT scans performed at a large academic healthcare system.

RESULTS

OP had a prevalence of 11.8% (n = 118) while occipital condyle pneumatization occurred in only 0.3%. Occipital air cells were right-sided in 27.1% (n = 32), left-sided in 51.7% (n = 61), and bilateral in 21.2% (n = 25), and OP was contiguous with the occipitomastoid suture. In cases of unilateral OP, the contralateral jugular foramen demonstrated relative enlargement (p = 0.006), but a direct association could not be established.

CONCLUSIONS

The occipital bone is an accessory site of skull base pneumatization in 11.8% of the population undergoing temporal bone CT, while air cell extension into the occipital condyle occurs more rarely. These occipital air cells have a left-sided predilection and are always in direct proximity to the occipitomastoid suture, suggesting developmental egress from the mastoid. OP is a normal variant and lacks features of craniocervical pneumatization, which is a rare disorder.

Infection of the spheno-occipital synchondrosis: A morbid complication following adenoidectomy

Two 2-year-old males presented post-operatively following adenoidectomy with persistent fever and neck stiffness. After multiple office visits, both patients were admitted and found to have a widened spheno-occipital synchondrosis and other imaging findings indicative of skull base osteomyelitis. Treatment with antibiotics allowed for recovery with good long-term outcomes. Infection involving the spheno-occiptal synchondrosis is rare and its circuitous presentation of these two children no doubt led to delayed diagnosis.

The Role of Surgical Debridement in Cases of Refractory Malignant Otitis Externa

Malignant Otitis externa is a necrotizing condition of external ear involving causing the osteomyelitis of the bone and surrounding soft tissue leading to multiple cranial nerve palsies. Though most patients respond to oral ciprofloxacin but due to emerging resistance cases of refractory malignant otitis externa which are unresponsive to antibiotic therapy for at least 6 weeks are being encountered lately. A study of 20 patients of refractory malignant otitis Externa was conducted at a tertiary care centre in north India; 10 patients were randomly allotted in group A and group B each. Group A was subjected to i/v ceftazidine 1 gm bd with oral ciprofloxacin 750 mg bd and Group B was subjected to surgical debridement with oral ciprofloxacin 750 mg bd. The improvement in symptoms was tabulated and statistical analysis was done using Mann-Whitney U test. There was better resolution of nocturnal pain in patients of group B who underwent surgical debridement although existing facial palsy didn't improve in both the groups. The improvement of symptoms in group B was statistically significant with P ≤ 0.05. We strongly recommend the role of surgical debridement in cases of refractory malignant otitis externa to relieve the patient of nocturnal pain. As the sample size of the study is small we are looking forward to the compilation of a multi institutional data so that a consensus on definitive protocol in cases unresponsive to oral multidrug therapy can be established.

The Role of the Otorhinolaryngologist in the Management of Central Skull Base Osteomyelitis

Background

Skull base osteomyelitis (SBO) typically evolves as a complication of external otitis in diabetic patients and involves the temporal bone. Central SBO (CSBO) mainly involves the sphenoid or occipital bones without coexisting external otitis. We characterized a group of patients with CSBO. The endoscopic nasopharyngeal and clival biopsy technique is described.

Methods

Medical records of patients diagnosed as having SBO were retrospectively analyzed (from 2001 to 2006). Patients’ symptoms and signs, laboratory findings, imaging characteristics, endoscopic clival and periclival histopathology results, treatment, and outcome were retrieved.

Results

Of 20 patients with SBO, 6 patients without external otitis were studied (age range, 54–76 years; 5 men; mean follow-up, 21 months). All patients suffered from unilateral headache, three of six patients had serous otitis media (SOM), three of six patients had cranial nerve (CN) palsies, and five of six patients had elevated acute-phase reactants. Computed tomography (CT) findings were clival cortical bone erosion and adjacent soft tissue swelling. Magnetic resonance (MR) findings were texture changes and enhancement of the involved bones and soft tissues. Biopsy specimens revealed chronic inflammation. All six patients were treated with antibiotics for 3–6 months. Headache disappeared in five of six patients, SOM resolved in two of three patients, and CN palsies partially recovered in two of three patients. Imaging findings improved in five of six patients.

Conclusion

CSBO may mimic malignancy and represents a diagnostic challenge. Typical clinical picture and imaging findings together with a positive response to ciprofloxacin may suffice to establish the diagnosis and obviate the need for biopsies. When in doubt, nasopharyngeal and clival biopsies are performed to rule out malignancy.

Advanced Imaging Techniques in Skull Base Osteomyelitis Due to Malignant Otitis Externa

PURPOSE OF REVIEW

To give an up-to-date overview of the strengths and weaknesses of current imaging modalities in diagnosis and follow-up of skull base osteomyelitis (SBO).

RECENT FINDINGS

CT and MRI are both used for anatomical imaging, and nuclear techniques aid in functional process imaging. Hybrid techniques PET-CT and PET-MRI are the newest modalities which combine imaging strengths.

SUMMARY

No single modality is able to address the scope of SBO. A combination of functional and anatomical imaging is needed, in the case of newly suspected SBO we suggest the use of PET-MRI (T1, T2, T1-FS-GADO, DWI) and separate HRCT for diagnosis and follow-up.

A Comprehensive Review of Skull Base Osteomyelitis: Diagnostic and Therapeutic Challenges among Various Presentations

Skull base osteomyelitis (SBO) is a complex and fatal clinical entity that is often misdiagnosed for malignancy. SBO is commonly a direct complication of otogenic, sinogenic, odontogenic, and rhinogenic infections and can present as central, atypical, or pediatric clival SBO. This review describes the clinical profile, investigational approach, and management techniques for these variants. A comprehensive literature review was performed in PubMed, MEDLINE, Research Gate, EMBASE, Wiley Online Library, and various Neurosurgical and Neurology journals with the keywords including: SBO, central or atypical SBO, fungal osteomyelitis, malignant otitis externa, temporal bone osteomyelitis, and clival osteomyelitis. Each manuscript's reference list was reviewed for potentially relevant articles. The search yielded a total of 153 articles. It was found that with early and aggressive culture guided long-term intravenous broad-spectrum antibiotic therapy decreases post-infection complications. In cases of widespread soft tissue involvement, an early aggressive surgical removal of infectious sequestra with preferentially Hyperbaric Oxygen (HBO) therapy is associated with better prognosis of disease, less neurologic sequelae and mortality rate. Complete resolution of the SBO cases may take several months. Since early treatment can improve mortality rates, it is paramount that the reporting radiologists and treating clinicians are aware of the cardinal diagnostic signs to improve clinical outcomes of the disease. It will decrease delayed diagnosis and under treatment of the condition. However, due to rarity of the condition, complete prognostic factors have not fully been analyzed and discussed in the literature.

Skull base osteomyelitis secondary to malignant otitis externa mimicking advanced nasopharyngeal cancer: MR imaging features at initial presentation

PURPOSE

Skull base osteomyelitis (SBOM) is an inflammatory process which often arises from malignant otitis externa (MOE); the diffuse skull base and adjacent soft tissue involvement may be mistaken at initial imaging for advanced nasopharyngeal carcinoma (NPC), especially if there is no prior knowledge of MOE, direct spread from the sphenoid sinus or in atypical presentations of MOE. This study aims to evaluate imaging features on MR that may differentiate SBOM from NPC.

MATERIALS AND METHODS

The MR examinations of 26 patients diagnosed with SBOM between January 1996 and January 2013 were retrospectively reviewed. Comparison was also made with the MR images of 22 consecutive patients with newly diagnosed advanced T3 and T4 NPC between July 2011 and August 2012. Imaging features in both conditions were compared, including the presence of a nasopharyngeal bulge, nasopharyngeal mucosal irregularity, lateral extension, architectural distortion (or lack thereof), increased T2 signal and enhancement patterns.

RESULTS

The most prevalent findings in SBOM were lateral extension, increased T2 signal in adjacent soft tissues, lack of architectural distortion and enhancement greater than or equal to mucosa. The combination of these 4 findings was found to best differentiate SBOM from advanced NPC, and found to be statistically significant (p<0.001).

CONCLUSION

We suggest that the combination of lateral extension, increased T2 signal, lack of architectural distortion and enhancement greater than or equal to mucosa is helpful in differentiating SBOM from advanced NPC.

Clinical Challenges in the Diagnosis and Treatment of Temporal Bone Osteomyelitis

Temporal bone osteomyelitis is a serious life-threatening condition—a quick and proper diagnosis is needed to start treatment and reduce morbidity and mortality. Changing trends of the disease make a differential diagnosis difficult. To emphasize the importance of a clinical suspicion of this dangerous condition, our experience with three difficult cases is presented. The diagnosis was based on clinical symptoms, otoscopic findings, and findings on computed tomography or magnetic resonance imaging. Neoplasm and granulomatous inflammation were excluded by multiple biopsies. The disease can develop in nondiabetic patients. The disorder might be related to the initial inflammatory process in the middle ear with further direct spreading of infection through defects in the bony walls to deep temporal bone structures. Imaging should be performed early to detect osteolytic lesions of the skull base. Surgery was used for the presence of bone sequestra and infratemporal abscess.

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.