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

OBJECTIVE: To determine the diagnostic accuracy of Necrotizing Otitis Externa (NOE) based on radiologic studies. METHODS: The PubMed, Cochrane, Embase, Web of Science, SCOPUS, and Google Scholar databases were searched. True-positive and false-negative results were extracted for each study. Methodological quality was evaluated using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. RESULTS: The included studies contained data on 37 studies diagnosed with NOE. The sensitivity of gallium-67, technetium-99m, and Magnetic Resonance Imaging (MRI) was 0.9378 (0.7688-0.9856), 0.9699 (0.8839-0.9927), and 0.9417 (0.6968-0.9913), respectively. For Computed Tomography (CT), the positive criteria consisted of bony erosion alone and bony erosion plus any soft tissue abnormality. The sensitivity of CT based only on bony erosion was 0.7062 (0.5954-0.7971); it was higher 0.9572 (0.9000-0.9823) when based on bony erosion plus any soft tissue abnormality. CONCLUSION: The diagnostic sensitivity of technetium-99m, gallium-67, and MRI was favorable. On CT, the presence of bony erosion may be a useful diagnostic marker of NOE, but the diagnostic sensitivity will be even higher if the criterion of any soft tissue abnormality is also included; however, care should be taken when interpreting the results. Our study demonstrates the potential utility of radiology studies for diagnosing NOE, but their lack of specificity must be considered, and standardized anatomic criteria are still needed. LEVEL OF EVIDENCE: 2A.

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.

Necrotising Otitis Externa: An Overview Of Imaging Modalities.

Necrotising Otitis Externa (NOE) has often posed some challenges in view of diagnosis and management by clinicians. One such challenge is the appropriate and timely use of imaging techniques, since its use is critical not only in diagnosis but also determining the extent and resolution of the disease. Hence, doctors in both primary and secondary health care need to be familiar with presenting symptoms, while specialists need to be appraised of advances in imagining techniques in management of NOE. Whilst there is a general consensus amongst clinicians on some aspects of management of NOE, there is very limited consensus on the use of imaging modalities. There is no single modality of imaging that can provide a complete picture of diagnosis, disease progression and resolution. There are some advantages and limitation of each methodology, which indicate that a multi-modal imaging technique at particular stages of the disease may provide better management outcomes. However, further research in this area is required, as there is not yet an established 'gold standard' for imaging in NOE.

Malignant External Otitis in a Patient With Diabetes Mellitus: Comparison of Bone Scan SPECT/CT and 68Ga-Citrate PET/CT.

ABSTRACT: We reported a 66-year-old woman with malignant external otitis who was referred to our department for evaluation of disease extension. Both 99mTc-MDP bone SPECT/CT and 68Ga-citrate PET/CT were done for the patient. Both studies showed concordant areas of increased uptake in the petrous bone. In addition, 68Ga-citrate PET/CT showed soft tissue infection in the nasopharyngeal wall. Our case showed the potential of 68Ga-citrate PET/CT for evaluation of malignant external otitis.

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.

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

PURPOSE: High-resolution temporal bone computer tomography (HRTBCT) is the most common initial radiological modality used for the assessment of necrotizing otitis externa (NOE). OBJECTIVES: (1) To compare the extension of disease, as seen on HRTBCT, in patients with NOE caused by different pathogens and (2) assess whether radiological findings may suggest the offending pathogen in cases of sterile-NOE. METHODS: All NOE patients were hospitalized between 1990 and 2018. All patients underwent HRTBCT at admission. Three groups (fungus-NOE, PA-NOE and sterile-NOE) comprising of ten patients each were randomly selected. HRTBCT was reevaluated by a senior radiologist. Thirteen radiological subsites were selected for reevaluation. RESULTS: All patients in the fungal-NOE group complained of otalgia, compared to nine in the sterile-NOE and six in the PA-NOE groups (p value = 0.044). External ear canal edema and granulation tissue were the most common findings in all groups. Surgery was performed in five patients in the fungal-NOE and PA-NOE and three in the sterile-NOE group (p value = > 0.05). Radiological findings indicating severe bone erosion within the EEC was seen in all patients but 3 (p value = > 0.05). Severe TMJ erosion was seen in one patient within the fungal-NOE and PA-NOE group (p value = > 0.05). When mild and severe involvement were combined, TMJ bone erosion was seen in four patients in the fungal-NOE and only in one patient in the PA-NOE (p = 0.04). CONCLUSIONS: TMJ involvement may be more common in fungal disease, suggesting a different spreading pathway, as opposed to PA-NOE. Accordingly, TMJ involvement on HRTBCT may justify antifungal treatment in sterile culture-NOE.

Malignant otitis externa: An updated review.

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

Aural CT characteristics of American Cocker Spaniels have features of both mesaticephalic and brachycephalic breeds.

Otitis externa and otitis media are common in American Cocker Spaniels, however breed-specific aural CT descriptions are currently lacking. This prospective and retrospective, observational, analytical study aimed to describe quantitative CT characteristics of the horizontal ear canal and the tympanic bulla in American Cocker Spaniels versus similar-sized mesaticephalic dogs. We prospectively performed clinical examinations and aural CT scanning for 38 American Cocker Spaniels. Computed tomographic transverse area of the osseous horizontal ear canal (TA1), transverse area of the widest air-filled part of the cartilaginous horizontal ear canal (TA2), tympanic bulla volume, and tympanic bulla wall thickness were measured. The TA1 and TA2 measurements were compared with those of 23 retrospectively recruited, similar-sized mesaticephalic dogs that had undergone CT-scanning of the head for non-ear-related reasons. The TA1 and TA2 did not differ for healthy American Cocker Spaniels and mesaticephalic dogs. Severely affected American Cocker Spaniels had significantly smaller TA2 (P < .001). The intraclass correlation coefficient for intraobserver and interobserver repeatability was 0.972 and 0.983 for TA1 and 0.994 and 0.998 for TA2, respectively. Variation between individuals was subjectively noted in healthy and affected American Cocker Spaniels, but mean tympanic bulla volume was slightly smaller in relation to body weight, and the tympanic bulla wall was thicker than in previous reports for mesaticephalic dogs. The tympanic bulla wall appeared thicker rostro-ventrally than caudo-ventrally in 44% of the dogs. Our results imply that a relatively thick tympanic bulla wall may be a normal CT variation and should be interpreted cautiously in this breed.

Aspergillus flavus malignant external otitis in a diabetic patient: case report and literature review.

PURPOSE: Malignant external otitis is an aggressive and potentially life-threatening infection. This rare disorder is typically caused by Pseudomonas aeruginosa and affects almost exclusively elderly diabetic patients. However, fungal malignant external otitis have been identified, especially in immunocompromised hosts. METHODS: We report a rare case of invasive malignant external otitis caused by Aspergillus flavus in a diabetic patient without other underlying immunosuppression. A review of Aspergillus spp. malignant external otitis since voriconazole became the first line for invasive aspergillosis was performed. RESULTS: A 72-year-old man with diabetes mellitus developed invasive malignant external otitis with a vascular involvement. The patient was treated with empiric courses of antibiotics until a fungal infection was diagnosed. Proven Apsergillus infection was based on histopathological examination and isolation of A. flavus from culture of osteo-meningeal biopsies. Despite optimal antimicrobial therapy with voriconazole, the patient presented with cerebral infarction in the setting of an angioinvasive fungal infection leading to a fatal outcome. From a review of the literature, we found 39 previously published cases of proven Aspergillus spp. malignant external otitis treated with new triazoles. CONCLUSION: Given our experience and the literature review, a fungal etiology should be considered early in the course of malignant external otitis unresponsive to a conventional broad spectrum antibiotic therapy, with the need for a tissue biopsy to confirm the diagnosis.

Clinical techniques in Veterinary Dermatology: Regional anaesthesia of the canine ear.

BACKGROUND: Video otoscopy is a valuable tool for the diagnosis and treatment of otitis externa (OE) and otitis media (OM) in dogs. Procedures performed by video otoscopy often are painful and it can be challenging to maintain steady anaesthetic depth and provide smooth anaesthetic recovery. A multimodal approach to analgesia and anaesthesia is ideal to minimize complications associated with high doses of anaesthetic drugs while providing the patient with adequate analgesia. HYPOTHESIS/OBJECTIVE: To describe a technique for regional anaesthesia of the canine ear. ANIMALS: One canine cadaver, obtained as part of a teaching laboratory class for other clinical techniques, with institutional approval, was used for illustration purposes. RESULTS: Clinical technique for regional anaesthesia of the canine ear. CONCLUSIONS AND CLINICAL IMPORTANCE: Nerve blocks for regional anaesthesia are an important aspect of a multimodal anaesthetic approach. A technique for blocking the two major sensory nerves to the canine ear is described.

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.

[Atypical skull base osteomyelitis suspected of spreading inflammation from the ear canal with unilateral multiple cranial neuropathy and cerebral infarctions].

A 76-year-old man, who had undergone surgery for esophageal cancer in 2010, presented to our hospital in April 2017 complaining of prolonged slight fever, loss of appetite, and dysphagia. Initial evaluation revealed a paralyzed left vocal cord, slight muscle weakness of the extremities, left facial paralysis, hoarseness, left sternocleidomastoid and trapezius muscle weakness, tongue deviation to the left, and left hypacusia-suggesting a diagnosis of Garcin's syndrome. Laboratory tests revealed increased white blood cells and C-reactive protein. Cerebrospinal fluid (CSF) analysis showed mild pleocytosis (predominantly polymorphonuclear cells), elevated protein, and low CSF/plasma glucose ratio. CT showed mild clival erosion, with no evidence of carcinoma recurrence. Brain contrast-enhanced MRI showed abnormal clival marrow, enhanced soft tissue and dura matter from the clivus to the atlantoaxial joint, enhanced soft tissue around the left ear canal, multiple cerebral infarctions in the left watershed zones, and left internal carotid stenosis. There was excessive ear wax and inflammation of the left external acoustic meatus but no otorrhea or otalgia. On the basis of his overall presentation, he was diagnosed with atypical skull base osteomyelitis due to external otitis. He was treated with antibiotic treatment that included ceftazidime for the Pseudomonas aeruginosa detected on bacterial cultures. He did not respond to treatment and died approximately 4 months later. Skull base osteomyelitis is thus an important differential diagnosis candidate after finding unilateral, multiple cranial neuropathy, underscoring the importance of prompt treatment when suspected.

Computed tomographic characteristics of pneumolabyrinth in a French bulldog with otitis media and externa.

A four-year-old female French bulldog was presented for evaluation of acute, left-sided peripheral vestibular syndrome. Computed tomographic (CT) examination of the head revealed the presence of air within the left cochlea and vestibule, consistent with pneumolabyrinth. This was concurrent with ipsilateral otitis media and externa. Pneumolabyrinth is an uncommon finding in humans and is most frequently due to head trauma and temporal bone fracture. This is the first report describing pneumolabyrinth in a dog, apparently of nontraumatic origin in this case.

FDG-PET/CT for diagnosis and follow-up of necrotizing (malignant) external otitis.

OBJECTIVE: Imaging is important for the diagnosis and follow-up of necrotizing external otitis (NEO). The best imaging modality is controversy. To suggest 2-deoxy-2-[fluorine-18] fluoro-D-glucose-positron emission tomography/computed tomography (18F-FDG-PET/CT) as an alternative to technetium-99m and gallium-67 scans for diagnosis and assessment of response to treatment for patients with NEO. STUDY DESIGN: Case series. METHODS: Tertiary referral center. From 2013 through 2017, 12 patients were diagnosed with NEO based on clinical features and positive FDG uptake within the temporal bone on PET/CT. Mean age was 74 ± 11.5; 83% of the patients were male; and 83% had diabetes. RESULTS: PET/CT scans were reviewed independently by two nuclear medicine specialists. Imaging located osteomyelitis in external ear canal, mastoid, temporomandibular joint, and nasopharyngeal region (100%, 50%, 16%, 8%, respectively). Mean follow-up was 16 months. Eight patients (67%) underwent a second PET/CT scan after active otitis resolved and after at least 6 weeks of antibiotic treatment. The scan demonstrated no or substantially reduced FDG uptake and treatment was stopped. The patients had no NEO symptoms at the end of follow-up. One patient had significant uptake, and antibiotic treatment was continued until a third scan demonstrated no FDG uptake. Two patients died before the second PET/CT, and two were lost to follow-up. CONCLUSION: 18F-FDG-PET/CT is a reliable imaging modality for diagnosis, disease localization, and decision making regarding treatment cessation. 18F-FDG-PET/CT should be considered as the imaging modality of choice for initial diagnosis and follow-up in NEO patients. Larger, controlled studies are warranted. LEVEL OF EVIDENCE: 4 Laryngoscope, 129:961-966, 2019.

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

OBJECTIVE: To survey neurotologists and head and neck radiologists regarding use of imaging in the diagnosis and management of necrotizing otitis externa (NOE). STUDY DESIGN: Cross-sectional survey study. SETTING: Online survey distributed through email to specialty society membership lists. PARTICIPANTS: Neurotologists and head and neck radiologists with membership in either the American Neurotology Society or The American Society of Head and Neck Radiology. MAIN OUTCOME MEASURES: Responses to survey consisting of two demographic and seven clinically oriented questions related to the use of imaging in the diagnosis and management of NOE. RESULTS: One hundred thirty-six participants responded to the survey. The imaging modality of choice in establishing the diagnosis of NOE selected by the respondents was computed tomography (CT) (37.5%) followed by technetium scintigraphy (21.3%). Magnetic resonance imaging (MRI) was the preferred investigation by 41.9% of participants for determining extent of disease. Gallium scanning was the imaging modality preferred by 32.4% of respondents for determining when to cease medical therapy. Ninety-five percent of participants responded that CT scans were always or frequently used in the diagnosis and management of NOE compared with 72.8% for MRI, 34.5% for gallium scans, and 34.2% for technetium scans. CONCLUSIONS: There is considerable heterogeneity in the preferred imaging modalities used in the diagnosis and management of NOE. CT and MRI are the preferred contemporary modalities used by many physicians, demonstrating a shift away from the historic use of nuclear medicine scans.