Necrotizing ("malignant") external otitis histopathologic processes

Skull Base Osteomyelitis: Historical Perspective, Diagnosis and Management Update

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

UK consensus definitions for necrotising otitis externa: a Delphi study

OBJECTIVE

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

DESIGN

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

SETTING

Secondary care in the UK.

PARTICIPANTS

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

MAIN OUTCOME MEASURES

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

RESULTS

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

CONCLUSIONS

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

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.

Rare Diseases of the Middle Ear and Lateral Skull Base

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

Skull Base Osteomyelitis: Diagnostic and Therapeutic Challenges in Atypical Presentation

OBJECTIVE: We sought to document the diagnostic and management difficulties in masked skull base osteomyelitis secondary to malignant otitis externa, with emphasis on establishing diagnostic criteria in recurrence.

STUDY DESIGN: Retrospective analysis of 3 cases of inadequately treated malignant otitis externa in elderly diabetic individuals leading to recurrence and atypical manifestations of skull base osteomyelitis on contralateral side with or without multiple cranial nerve involvement.

RESULTS: Two of the 3 cases died of the disease despite aggressive treatment. One case was treated successfully with combination of antipsuedamonal microbial drugs for 8 to 12 weeks and hyperbaric oxygen therapy. Major complications such as thrombosis of lateral sinus and internal jugular vein, meningitis, ophthalmoplegia, blindness, cervical spine erosion and paralysis of all cranial nerves with exception of Ist cranial nerve were observed.

CONCLUSION: There is high morbitity and mortality associated with skull base osteomyelitis. In partially treated cases of malignant otitis externa, atypical symptoms and findings of unilateral severe otalgia, unremitting headache, and presence of high ESR, unilateral OME, constitute diagnostic clues of skull base osteomyelitis. Such cases require further investigation with CT, MRI, Technetium 99 and gallium 67 scintigraphy and aggressive management.

Bilateral skull base osteomyelitis in an immunocompetent patient

A 75-year-old immunocompetent man presented to our office with right otalgia. After a comprehensive workup, he was found to have right temporal bone osteomyelitis and was treated with intravenous antibiotics. He then began to experience left-sided otalgia and was diagnosed with and treated for left temporal bone osteomyelitis. Subsequently, he began to exhibit myelopathic symptoms, and imaging revealed a C2 inflammatory process. The patient underwent endoscopic transoral odontoidectomy with resection of a large C1 to C2 pannus and recovered with no neurologic deficit. Skull base osteomyelitis is an uncommon condition that usually occurs in immunocompromised patients. Prompt diagnosis and appropriate treatment are of utmost importance in managing this condition.

Hypertrophic cranial pachymeningitis and skull base osteomyelitis by pseudomonas aeruginosa: case report and review of the literature

Hypertrophic cranial pachymeningitis (HCP) is an uncommon disorder characterized by localized or diffuse thickening of the dura mater, and it usually presents with multiple cranial neurophaties. It has been associated with a variety of inflammatory, infectious, traumatic, toxic and neoplasic diseases, when no specific cause is found the process is called idiopathic. The infectious cases occur in patients under systemic immunosuppression, which have an evident contiguous source or those who have undergone neurosurgical procedures. We describe a case of a 62-year-old immunosuppressed woman with diabetes and rheumatoid arthritis, which had HCP and osteomyelitis of the skull base caused by pseudomonas aeruginosa, presenting with headache and diplopia. We believe this is the second documented case of pachymeningitis secondary to this microorganism. As a multifactorial disease, it is essencial to determine the specific causative agent of HCP before making treatment decisions, and great care is needed with immunocompromised patients.

Osteomyelitis of the temporal bone and skull base in diabetes resulting from otitis media

The report of a diabetic patient with pseudomonal osteomyelitis of the temporal bone and skull base not associated with an external otitis is presented. The infection started as a serous otitis media. The pathogenesis, clinical and radiologic features, and treatment of this rare condition are described and the literature is reviewed.

Malignant otitis externa: case series

BACKGROUND

In the light of current concerns regarding ciprofloxacin resistance and the changing face of malignant otitis externa, we reviewed cases of malignant otitis externa treated in our centre, in order both to evaluate the current epidemiology of the condition and to assess the status of drug resistance in our patient population.

METHOD

Retrospective case review of all malignant otitis externa cases managed in a tertiary referral centre in the north-east of England between 2000 and 2009.

RESULTS

Forty-one patients were identified, but the required data were available for only 37 cases. Patients' ages ranged from 51 to 101 years (median, 81 years). Diabetes was present in 51 per cent of patients (19/37), facial nerve palsy in 40 per cent (15/37) and multiple cranial nerve palsy in 24 per cent (9/37). Pseudomonas aeruginosa was the most commonly isolated organism (54 per cent), sensitive to ciprofloxacin in all cases.

CONCLUSIONS

The incidence of cranial nerve palsy in our study was higher than in previous reports. The incidence of diabetes and Pseudomonas aeruginosa in our cohort was much lower than previously reported. The Pseudomonas aeruginosa strains isolated were all sensitive to ciprofloxacin, despite recent reports on emerging resistance.

Prognostic scoring in necrotising otitis externa

Objective:

To collect and analyse data from the published literature concerning the rare condition necrotising otitis externa, in order to formulate a prognostic scoring model based on signs and symptoms.

Design:

Retrospective data collection from published literature, and binary logistic regression analysis of the effect on outcome of identified signs and symptoms.

Results:

Six factors were identified as prognostic of a poorer outcome, including facial nerve involvement, additional cranial nerve involvement, non-cranial nerve neurological involvement, extensive granulations (or oedema) in the external auditory canal, bilateral symptoms and aspergillus species as the causative organism. A four-point scoring model based on these findings is presented.

Conclusions:

A novel, systematic method of data analysis was utilised to construct a prognostic scoring model for necrotising otitis externa. This will better equip clinicians to treat this potentially fatal condition.

Petrositis and cerebellar abscess complicating chronic otitis media

A 12-year-old girl with chronic otitis media complicated by petrositis and cerebellar abscess is presented. Early surgical intervention, in combination with broad-spectrum antibiotics, provided a good outcome. Life-threatening complications of otitis media, although rare, still occur in developed countries.

Skull base osteomyelitis secondary to malignant otitis externa

PURPOSE OF REVIEW

Skull base osteomyelitis secondary to malignant otitis externa was first described in 1959. Since then, advances have been made in the diagnosis, treatment, and clinical outcomes of this condition.

RECENT FINDINGS

This review discusses the pathophysiology and microbiology of malignant otitis externa. The review highlights the sometimes subtle presenting symptoms and recent advances in imaging and their practical application to diagnosing and monitoring the disease. Therapy for malignant otitis externa has changed since this entity was first described; this article reviews the medical, surgical, and adjuvant therapies and the relevant controversies.

SUMMARY

The review discusses the history, pathogenesis, diagnosis, and treatment of skull base osteomyelitis in the context of malignant otitis externa with particular emphasis on HIV, children, and other immunodeficient states.

CT and MRI in malignant external otitis: a report of four cases

Malignant external otitis (MEO) is a severe infection of the external auditory canal and skull base which most often affects elderly patients with diabetes mellitus. Early diagnosis and aggressive treatment are important in terms of reducing risks of dissemination. We report four cases of MEO in patients with diabetes mellitus who were observed with computed tomography (CT) and/or magnetic resonance imaging (MRI). MRI was superior to CT in patients with MEO in terms of estimating the anatomic extent of the disease, but it cannot be used for monitoring therapy.

Histopathology of the soft parts in 50 patients with malignant external otitis

Reports concerning the lesions of the skin coverage of the external ear canal in malignant external otitis (M.E.O.) are very few. To evaluate this problem, we studied the skin lesions of 45 skin biopsies from 40 M.E.O. patients, 23 from regions covering the osseous part of the ear structure, seven from the cartilaginous part of the external canal and 15 from both parts. The epidermis was normal in nine, thickened in 16, with acanthotic thickening and pseudoepitheliomatous hyperplasia in 20. In the dermis the amount of collagen was normal, but it was infiltrated by the inflammatory process. Acute inflammation was observed in 16 biopsies, subacute in 23, chronic in six. A mixture of acute and chronic changes was present in 18 biopsies. No major abnormalities of the vasculature could be detected. The distinguishing pathological feature of M.E.O. concerns the typical topographic distribution of the inflammation in the osseous part of the external ear canal.

Pseudomonas labyrinthitis

Pseudomonas aeruginosa is the gram-negative bacterial rod which is often isolated from chronic aural discharge. This microorganism may also cause necrotizing infection of the external auditory canal in certain patients with impaired host-defense mechanisms. Involvement of the inner ear by this microbe is extremely rare. In this communication, we report a case of pseudomonas labyrinthitis which resulted from traumatic middle ear injury. Infection produced massive granulations and extensive bone destruction of the otic capsule. This case shows that while P.aeruginosa is usually an avirulent opportunistic pathogen, it may also cause a highly destructive labyrinthitis if the inner ear is entered.

Malignant external otitis in a young diabetic patient

A case of malignant external otitis in a young diabetic is reported. This entity should be suspected in diabetics of all ages and in all immune-deficient patients presenting with aural discharge, associated with a dehiscence of the meatal wall, meatal granulations or post-aural abcess. Gentamicin/Carbenicillin combination obviated the need for major surgery.

Malignant external otitis: a dangerous misnomer?

Review of our experience in treating 16 patients with malignant external otitis, along with survey of the compromised defense mechanisms of diabetic patients, confirms the need for immediate, intense, and vigilant therapy. Radioisotope scans, high-resolution computed tomography scans, and multidirectional tomograms are used to delineate the extent of the disease. Therapy includes intravenous aminoglycoside and penicillin derivatives, limited surgery, and hyperbaric oxygenation. In view of the tendency for this infection to extend beyond the external auditory canal and to produce an invasive lethal osteomyelitis, we feel that the tendency to classify this disease as a variant of diffuse external otitis may foster undertreatment.

Invasive external otitis. Report of 21 cases and review of the literature

We report 21 cases of invasive external otitis and review 130 cases from the English literature. Invasive external otitis is the term that most appropriately describes the locally invasive Pseudomonas infections that begins in the external ear canal, breaches the epithelial barrier and results in signs of local subcutaneous tissue invasion. Nineteen patients were diabetic. FIfteen of these 19 had preexistent, long-standing diabetes (average 15.8 years) and 10 had microvascular disease. Studies of the skin of the temporal bone in two patients provided evidence of diabetic microangiopathy of the dermal capillaries. Pseudomonas aeruginosa was isolated from the involved area in all cases. All patients without neurologic deficits survived, compared with six of nine with deficits of the central nervous system. All 13 patients in whom initial therapy was successful received a combination of an aminoglycoside and a semisynthetic penicillin, whereas all six episodes of recurrent disease occurred when only one antibiotic was used. The overall mortality was 15 percent (three of 20 in whom the long-term outcome is known). We propose that diabetic microangiopathy of the skin of the temporal bone results in poor local perfusion and creates an environment well suited for invasion by Pseudomonas aeruginosa. There is a good correlation between the extent of disease clinically and prognosis. Effective treatment requires early diagnosis and combination therapy with an aminoglycoside and a semisynthetic penicillin.

Temporal bone histopathology of necrotizing external otitis. A case report

Histopathological examination of the temporal bone of an individual with necrotizing external otitis revealed severe inflammation with necrosis in the subcutaneous granulation tissue in the external auditory canal. Erosion of the bony walls of the canal had created a defect in the anterior wall, through which infection spread to the preauricular region. The lateral part of the middle ear cavity was also filled with granulation tissue and purulent exudate. A dehiscence of the horizontal portion of the facial canal had apparently allowed spread of an inflammatory round cell infiltrate along the facial nerve up to the fundus of the internal auditory canal. The only evidence of inner ear pathology was the presence of eosinophilic fluid material in the perilymphatic spaces of the labyrinth. A review of other reports of cases of necrotizing external otitis seems to show that this is the only instance of this disease in which infection spread from the external canal through the tympanic membrane to the middle ear and thence to the internal auditory canal.

Histopathology of Pseudomonas osteomyelitis of the temporal bone starting as malignant external otitis

Although the natural history and treatment of "malignant external otitis" have been well described, available histopathologic data are limited to three case reports. The histopathology in two additional cases, in which the disease process was advanced and uncontrolled, is presented to illustrate the unique progression of temporal bone osteomyelitis due to the Pseudomonas organism. In both cases the bony labyrinthine capsule demonstrated remarkable resistance to the osteomyelitic process even though the infection seemed to pass around the inner ear from all sides. The most active area of osteomyelitis was at the skull base along the sigmoid sulcus, posterior fossa surface of the temporal bone, and petrous apex. Spread to the opposite petrous apex occurred anterior to the foramen magnum via the basisphenoid, cavernous sinus, and peritubal areas. The clinical and histopathologic data demonstrated that the disease process had a similar progression in both cases, starting in the external auditory canal with spread to the stylomastoid and jugular foramina. This resulted in septic thrombosis of the lateral venous sinus and subsequent extension to the petrous apex from both posterior and middle fossa surfaces of the petrous bone. The infection spread along vascular and fascial planes rather than through pneumatized tracts of the temporal bone. The treatment of this disease is discussed in the light of the histopathologic findings.