Fungal malignant external otitis

doi:10.1016/j.jinf.2011.01.001

Journal of Infection

Volume 62, Issue 3, March 2011, Pages 226-231

https://doi.org/10.1016/j.jinf.2011.01.001 Get rights and content

Summary

Objective

To investigate the clinical characteristics and outcome of fungal malignant external otitis (MEO).

Methods

The files of 60 patients treated for MEO in 1990–2008 at a tertiary medical center were reviewed for clinical characteristics and outcome, and findings were compared between patients with fungal and nonfungal infection.

Results

Mean duration of follow-up was 4 years. Nine patients (15%) had fungal disease; the main pathogen was Candida spp. Compared with the nonfungal MEO group, patients with a fungal infection were younger at diagnosis (average 68 vs. 74 years, p = 0.01) and had more facial nerve palsies (55% vs. 14%, p = 0.01), fewer positive bacterial cultures at presentation (33% vs. 75%, p = 0.02), and higher rates of surgery (78% vs. 18%, p = 0.0008) and hyperbaric treatment (78% vs. 4%, p = 0.0001). Eighty-nine percent had persistent infection (>2 courses of systemic antibiotics before antifungal treatment) compared with 12% in the nonfungal group (p = 0.0001). Fungal disease was associated with more persistently positive imaging findings (87.5% vs. 25%, p = 0.0001). There was no significant between-group difference in survival.

Conclusion

Fungal MEO probably occurs secondary to prolonged antibiotic treatment for bacterial MEO. The fungal disease is more invasive than the bacterial disease, although survival is the same. Treatment should be aggressive and hyperbaric oxygen therapy should be considered.

Introduction

Malignant external otitis (MEO), also known as necrotizing external otitis, is an aggressive and potentially fatal infection that originates in the external ear canal and spreads progressively along the soft tissues and bone of the skull base, ultimately involving intracranial structures.¹ This rare disorder occurs almost exclusively in elderly and diabetic patients.1, 2

Since Chandler’s publication of the first comprehensive case series of MEO in 1968,¹ the most commonly reported causative pathogen has been Pseudomonas aeruginosa (>98% of cases).³ Other pathogens include Staphylococcus aureus,⁴ Staphylococcus epidermidis,⁵ Proteus mirabilis,⁶ and Klebsiella oxytoca.⁷ Fungi are rarely involved in MEO, and have been identified particularly in immune-compromised nondiabetic patients, such as patients with AIDS or acute leukemia.2, 8 Aspergillus fumigates is the most common cause of fungal MEO.8, 9

The traditional and well-accepted treatment for MEO is prolonged anti-pseudomonal therapy for at least 6 weeks as well as local treatment with lavage and eardrops. When cure is not achieved after 6 weeks, the antibiotic treatment is continued and other treatment modalities are considered, such as surgery for debridement10, 11, 12, 13 and hyperbaric oxygen chamber.14, 15, 16

Only few studies have focused on fungal MEO, and most of them are case reports. In a previous study by our group of severe MEO,¹¹ cultures of specimens from the external canal were positive for fungi in almost half the patients with a persistent course. The aim of the present study was to describe patients with fungal infection and to further investigate the clinical characteristics and outcome of fungal MEO compared to nonfungal MEO.

The database of the department of otorhinolaryngology of a tertiary, university-affiliated medical center was searched for all patients hospitalized with MEO between 1990 and 2008. The diagnosis of MEO was based on the following criteria:

1.
External otitis not responsive to outpatient treatment of at least one week.
2.
Clinical findings of severe otalgia, edema, and exudates of the external ear canal, and/or granulation tissue at the external ear canal.
3.
Positive findings on bone scan (technetium with or without gallium).
4.
Histological exclusion of other causes of external otitis, such as tumors and cholesteatoma.
5.
Microabscess on pathology specimens obtained at surgery, if performed.

In addition, MEO was diagnosed when one criterion was not fulfilled but the disease failed to improve after one week of intravenous antibiotics and extensive local treatment.

Our treatment protocol for MEO consisted of intravenous ceftazidime, local eardrops, and daily ear lavage. Patients in whom the disease improved within 2 weeks were discharged and instructed to complete 6 weeks of treatment with oral ciprofloxacin or intravenous ceftazidime at home, administered by the home-care unit. Those who did not improve remained in hospital, and their antibiotic treatment was readjusted according to the culture results. In those who failed to respond to antibiotic treatment after 4 weeks, surgical debridement or hyperbaric chamber treatment was considered, according to the clinical and radiological findings. A persistent infection was defined as failure to improve after 2 full courses of systemic antibiotic treatment (>3 months).

Hyperbaric treatment, when considered necessary, was administered according to the Marx protocol,¹⁷ consisting of multiple once-daily sessions of breathing 100% oxygen under 2 ATA in a multi-seat hyperbaric chamber. Each session was divided into 3 equal periods of 30 min, with a 10-min interval before and after each period for pressure compression and decompression, respectively, with air breathing.

In our institution, ear tissue samples from patients with MEO are routinely cultured for both bacteria and fungi. In our patients with negative cultures who had an ongoing active disease, ear tissue samples were analyzed by panbacterial and panfungal 16sRNA polymerase chain reaction (PCR). Those with positive microbiological findings of fungal infection received antifungal treatment. Cure was defined as complete clinical resolution of symptoms and a negative gallium scan.

For purposes of the study, the patients’ medical records were reviewed for medical background, clinical characteristics, culture and imaging findings, management, and outcome. Findings were compared between patients with fungal and nonfungal MEO.

Continuous variables are given as mean ± standard deviation. Differences in mean age between groups were analyzed with the Mann–Whitney U test. To analyze statistically significant differences in the distribution of the categorical variables between the two groups, chi-square or Fisher exact test was performed, as appropriate. Survival was calculated from the date of diagnosis to the date of death or last follow-up using the Kaplan–Meier method; log-rank test was applied to compare survival curves between groups. P values less than or equal to 0.05 were considered statistically significant. For statistical analyses, we used SPSS 15.0.1 software (SPSS Inc., Chicago, IL, USA).

Section snippets

Results

A total of 60 patients (39 male and 21 female) were diagnosed with MEO during the study period, of which 9 (15%) had a fungal infection. The characteristics of the patients with fungal and nonfungal disease are summarized in Table 1.

Discussion

To the best of our knowledge, this is the first case series of fungal MEO reported in the English literature. As part of our department’s wide experience with MEO,10, 18 we have observed that some patients have a persistent disease course (defined as >3 months of systemic antibiotic treatment), and that among this subgroup, the prevalence of fungal infection is relatively high (57%).

In the present study of 9 patients diagnosed with fungal MEO over an 18-year period, we found that fungal culture

Conclusion

Fungal MEO probably occurs secondary to prolonged antibiotic treatment in patients with primary bacterial MEO. Although fungal MEO is more invasive than bacterial MEO, as evidenced by imaging studies, the higher prevalence of facial nerve palsy, the greater need for surgical procedures, and the prolonged persistent course, there is no difference between the two infections in patient survival.

Since the outcome of fungal MEO is grim, aggressive treatment should be offered as early as possible.

Funding

No funding was received for this study.

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Ear Infections: Fungi
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Otomycosis is a pathological entity that is increasingly found in ENT clinical practrice. It is widespread worldwide and can affect any age. Fungal infections of the ear can be divided in external otomycosis, fungal malignant external otitis (FMEO), otomycosis of the midde ear and inner ear fungal infection. In the first case the main risk factors are dermatitis of external auditory meatus, use and abuse of earplugs and eardrops, swimming in polluted waters, self-injuries and immunodeficiencies. FMEO is typical of diabetic patients and can lead to dramatic consequences due to the spread along the soft tissues and the skull bones. Otomycosis of the middle ear can represent a complication of previous mastoidectomy or pre-existing cholesteatoma. The diagnosis of otomycosis is based on microscopic examination of aural secretions and colture of pathological discharge, biopsies made under otomicroscopy and/or intraoperatively, imaging investigation (computed tomography and resonance magnetic imaging above all) especially for FMEO and otomycosis of the middle ear. The treatment includes accurate ear toilette followed by application of topical antifungal eardrops; only in the most serious cases intravenous antimycotic therapy is indicated with or without surgical approach.
Place of isotopic explorations in necrotizing external otitis
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L’otite externe nécrosante (OEN) est potentiellement létale, survenant essentiellement chez des patients âgés diabétiques. Le but de notre travail était d’étudier l’apport des explorations isotopiques dans la confirmation diagnostique, le bilan d’extension et le suivi de l’OEN.
Notre étude rétrospective portait sur 50 patients présentant une forte suspicion d’OEN et qui ont bénéficié d’une scintigraphie osseuse et/ou au gallium.
Il s’agissait de 38 hommes et 12 femmes d’âge moyen de 68 ans. Tous étaient diabétiques. Le signe clinique le plus fréquent était l’otalgie (98 % des cas). La sensibilité de la tomodensitométrie, pratiquée dans 84 % des cas, était de 66,6 % des cas. La scintigraphie osseuse (SO), pratiquée chez tous les patients, montrait une hyperfixation temporale dans 90 % des cas. Une extension aux structures avoisinantes était objectivée dans 26 % des cas. La scintigraphie au gallium, réalisée dans 56 % des cas, avait objectivé une hyperfixation temporale pour 43 % d’entre eux. Seule l’association entre une lyse tympanale étendue à la tomodensitométrie et une scintigraphie osseuse positive était statistiquement significative (p = 0,036). Aucune corrélation statistiquement significative n’a été démontrée entre toutes les autres anomalies tomodensitométriques, ainsi que les signes cliniques, biologiques d’une part et de la positivité de la SO.
Les explorations isotopiques étaient d’un grand apport dans la prise en charge des OEN. La SO permettait d’affirmer très tôt l’existence d’une ostéomyélite de la base du crâne. Au cours du suivi, la scintigraphie au gallium permettait de suivre l’évolution de la maladie.
The necrotizing otitis externa (NOE) is potentially lethal which mainly occurs on the most among the elderly and diabetic. The aim of our study was to evaluate the contribution of isotopic explorations in diagnosis, staging and monitoring of the NOE.
Our retrospective study was about 50 patients with a strong suspicion of NOE who benefited a bone and/or gallium scintigraphy.
Our population was composed of 38 men and 12 women with mean age of 68 years. All patients were diabetic. The most common complaint was otalgia (98% of cases). The sensitivity of computed tomography (CT) which was performed in 84% of cases was 66.6% of cases. Bone scintigraphy (BS) was performed in all patients showing increased uptake in the temporal region in 90% of cases. An extension to surrounding structures was objectified in 26% of cases. Follow-up Ga 67 SPECT was performed in 56% of cases, demonstrated increased uptake at the temporal region in 43% of cases. The statistical study showed that only the presence of an extended tympanic lysis on CT was statistically significant to the positivity of BS (P = 0.036). No statistically significant correlation was found between all other CT abnormalities, clinical and biological signs and the positivity of bone scintigraphy.
Isotopic explorations were a great contribution in the management of the NOE. At the initial phase, the BS allowed to confirm very early an existence of osteomyelitis of the skull base. During the follow-up, the gallium-67 scan allowed the following of the evolution of infectious process.
Beware of covert enemies: Candida orthopsilosis malignant otitis externa with base of the skull osteomyelitis, a case report and review of literature
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With better assessment and diagnostic techniques, Candida species is also becoming a recognized isolated pathogen(9) Reviewing previously published cases, Hamzany et al., reviewed 60 patients with MOE diagnosed between 1990 and 2008 at a tertiary center, 9 of which (15 %) were caused by fungal etiology predominately Candida species mainly Candida albicans [9]. Interestingly, although the incidence of diabetes mellitus was comparable in patients with bacterial and fungal pathology, neurological complications were more frequent with the latter (14 % vs 55 %).
Malignant otitis externa (MOE) is a serious infection of the external auditory canal that is frequently associated with skull base osteomyelitis (SBO) as well as secondary neurological sequelae. Patients with poorly controlled diabetes mellitus or immunosuppression are at increased risk of developing such critical infection for multiple local and systemic factors. While most cases are secondary to bacterial infections particularlyPseudomonas aeruginosa, fungal infections are also occasionally encountered, often associated with delayed diagnosis and high morbidity and mortality.
We report a case of a 63 years old man with uncontrolled diabetes mellitus who presented with symptoms and signs of MOE, supported by radiological assessments. The patient was treated presumptively with a prolonged course of antibiotics without clinical improvement, coupled with progression of radiological findings and significant disease extension. Reassessment with biopsies and tissue cultures from external auditory meatus, tempo-mandibular bone, as well as base of the skull grew Candida orthopsilosis. The patient received induction treatment with high dose liposomal amphotericin followed by fluconazole to control disease progression and complications.
Candida MOE with secondary skull base osteomyelitis is rare and difficult to diagnose with no clear guidance on assessment and management. Clinicians should be aware of the unusual presentations where microbiological and histopathological evaluations are essential for proper management.
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Voriconazole therapy was continued for seven months. Fungal malignant otitis externa accounts for 10%–15% of all malignant otitis externa [3,4]. The most frequently reported are Aspergillus spp. and Candida spp [2].
A 77-year-old immunocompetent man was clinically diagnosed with right malignant otitis externa. He had been receiving combined antibiotics for five months for another illness. No etiologic agent was identified from aural discharge culture. Tympanomastoidectomy was done after no response was seen to empirical antibiotics. Tissue culture revealed Fusarium species and he was successfully treated with voriconazole.
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Fungal MOE is also associated with underlying chronic sinusitis and may also occur secondary to prolonged antibiotic treatment for MOE [25]. Aspergillus and Candida are the most common fungal species involved in MOE [25-28]. In patients with HIV, infection with P. aeruginosa is thought to more commonly occur with CD4 counts of <100/mm3 and Aspergillus with CD4 counts < 50/mm3 [23].
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MOE is an invasive external ear infection that spreads to the temporal bone and can further progress to affect intracranial structures. Complications of advanced MOE include cranial nerve involvement, most commonly the facial nerve, and intracranial infections such as abscess and meningitis. The most common causative agent of MOE is Pseudomonas aeruginosa, but others include methicillin-resistant Staphylococcus aureus and fungi. Major risk factors for MOE include diabetes mellitus, immunosuppression, and advanced age. Red flags for MOE include severe otalgia (pain out of proportion to exam) or severe otorrhea, neurologic deficits (especially facial nerve involvement), previously diagnosed otitis externa not responsive to therapy, and patients with major risk factors for MOE. Examination may show purulent otorrhea or granulation tissue in the EAC, and culture of EAC drainage should be performed. Diagnosis is aided by computed tomography (CT) with intravenous contrast, which may demonstrate bony destruction of the temporal bone or skull base. When suspecting MOE, early consultation with an otolaryngologist is recommended and antibiotics with pseudomonal coverage are needed. Most patients with MOE will require admission to the hospital.
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Fungal malignant external otitis

Summary

Objective

Methods

Results

Conclusion

Introduction

Section snippets

Results

Discussion

Conclusion

Funding

Am J Med

Otolaryngol Clin North Am

Int J Infect Dis

J Oral Maxillofac Surg

PMR

Otolaryngol Clin North Am

Otolaryngol Clin North Am

Malignant external otitis

Laryngoscope

Skull base osteomyelitis. Malignant external otitis

Otolaryngol Clin North Am

Staphylococcal malignant external otitis

Can Med Assoc J

Necrotizing "malignant" external otitis caused by Staphylococcus epidermidis

Arch Otolaryngol Head Neck Surg

Malignant external otitis in infants

Laryngoscope