Cranial Nerve Involvement in Malignant External Otitis: Implications for Clinical Outcome

BACKGROUND

Malignant external otitis is an uncommon, potentially lethal infection of the temporal bone primarily affecting elderly diabetic patients.

OBJECTIVE

To determine whether cranial nerve involvement in malignant external otitis affects or predicts the clinical outcome in terms of morbidity and mortality.

METHODS

Diagnosis of malignant external otitis was established in 23 patients (average age, 71 yr; range, 39-87) based on inclusion criteria of severe pain, otitis externa refractory to conventional treatments, diabetes mellitus, and Pseudomonas aeruginosa detection. Computed tomography confirmed temporal bone involvement extending outside the external auditory canal.

DATA ANALYSIS

Retrospective analysis of hospital records.

RESULTS

Ten of 23 (43.5%) patients showed cranial nerve involvement. The following cranial nerves were affected: facial nerve (6/10), lower cranial nerves (combination of IX, X, XI, XII) (3/10), and extended nerve palsy (VI, VII, IX, X, XI) (1/10). Thirteen of 23 (56.5%) patients displayed no cranial nerve involvement. All patients were treated with long-term, high-dose antibiotic treatment dependent on the microbiological findings.

CONCLUSIONS

All patients with lower cranial nerve palsy recovered normal function; however, the facial nerve palsy was significantly less likely to improve by medical treatment. Cranial nerve involvement did not affect the patient survival rate under an optimized medical treatment in our series.

Comparison of an antifungal agent with a mixture of antifungal, antibiotic and corticosteroid agents for the treatment of Malassezia species otitis in dogs

Twenty dogs with otitis externa in both ears and numerous Malassezia species yeasts on cytological examination were treated in one ear with a combination product containing clotrimazole, marbofloxacin and dexamethasone, and in the other ear with a topical antifungal containing miconazole. The effects of the treatments were analysed on the basis of the scores for pruritus, erythema and amount of cerumen, and the number of yeasts on cytological smears. There were reductions in the counts of Malassezia species after both treatments, but the combination product gave significantly greater reductions in erythema, cerumen and pruritus.

In vitro antimicrobial activity of the leaf extract of Harungana madagascariensis Lam. Ex Poir. (Hypericaceae) against strains causing otitis externa in dogs and cats

Otitis externa in dogs and cats is always caused by a combination of yeasts and bacteria, among which the most important are Malassezia pachydermatis, Staphylococcus intermedius and Pseudomonas species. These organisms often develop resistance to classical antimicrobial agents. Therefore, the aim of this study was to investigate the antimicrobial activities of an ethyl acetate leaf extract of Harungana madagascariensis against the organisms cited, to carry out the phytochemical investigation of this extract and to determine its bioactive chemical class using dilution techniques, the bioautography method and the standard phytochemical method described by Harborne (1973). Phytochemical analysis revealed the presence of saponins, tannins, flavonoids, alkaloids and anthracenic derivatives. The bioassay showed that the antimicrobial properties may be attributed to astilbin, a flavanone derivative identified on the basis of its spectroscopic data. The results suggest that the extract could be used in an antimicrobial preparation effective against the whole range of organisms incriminated in otitis externa in dogs and cats, with a minimal inhibitory concentration (MIC) of 250 microg/ml.

[Pseudomonas and acute external otitis. Results of a microbiological study in patients without previous antibiotic treatment]

We report the results of a microbiological clinic study that was performed by our ENT Department between years 2000 and 2001 whose main objective was to determine, in Badajoz Area of Health, which bacteria were involved in the acute diffuse external otitis of patients without previous antibiotic treatment (two weeks before obtaining the samples). Of 79 isolated microorganisms in 62 patients that fulfilled the requirements established Pseudomonas, mainly P. Aeruginosa, represented a 46.83% altogether followed by Staphylococcus (18.98%). In almost one fourth part of the cases strains of associated fungi were identified.

A case of malignant otitis externa caused by Candida glabrata in a patient receiving haemodialysis

A 74-y-old male receiving haemodialysis presented with right-sided otalgia, otorrhoea and diffuse swelling on the right external auditory canal. Following an initial successful treatment with prolonged intravenous antibiotics, the patient relapsed with a secondary infection in the same site due to Candida glabrata. We report an unusual case of malignant otitis externa caused by the fungus C. glabrata.

[Malignant external otitis]

Malignant external otitis or skull base osteomyelitis and osteoradionecrosis of the skull base and the skull are potentially life-threatening conditions. The standard methods of treatment involve the use of antibiotics, local treatment and, where necessary, surgical excision of necrotic tissue. These approaches do not provide a complete cure in many cases. Severe functional deficits and even death can occur in advanced stages. We conducted a long-term retrospective follow-up study and report on a multimodal approach that we have been using with great success since 1987. The four cornerstones of this treatment are surgical debridement, combinations of antibiotics, specific immunoglobulins, and adjunctive hyperbaric oxygen therapy. This multimodal treatment approach has proved to be highly effective in improving the survival and quality of life of the patients concerned. These excellent outcomes justify the high costs that this therapy admittedly involves.

Otitis externa: Review and clinical update

Otitis externa can take an acute or a chronic form, with the acute form affecting four in 1,000 persons annually and the chronic form affecting 3 to 5 percent of the population. Acute disease commonly results from bacterial (90 percent of cases) or fungal (10 percent of cases) overgrowth in an ear canal subjected to excess moisture or to local trauma. Chronic disease often is part of a more generalized dermatologic or allergic problem. Symptoms of early acute and most chronic disease include pruritus and local discomfort. If left untreated, acute disease can be followed by canal edema, discharge, and pain, and eventually by extra-canal manifestations. Topical application of an acidifying solution is usually adequate in treating early disease. An antimicrobial-containing ototopical is the preferred treatment for later-stage acute disease, and oral antibiotic therapy is reserved for advanced disease or those who are immunocompromised. Preventive measures reduce recurrences and typically involve minimizing ear canal moisture, trauma, or exposure to materials that incite local irritation or contact dermatitis.

Malassezia pachydermatis isolated from normal and diseased external ear canals in dogs: A comparative analysis

To investigate the role of Malassezia pachydermatis as a pathogenic agent in canine otitis, a comparative analysis of isolates from normal and diseased external ear canals in dogs was undertaken. Specimens were collected from the ears of dogs with unilateral or bilateral otitis and from healthy dogs. Mycological analysis was by direct microscopy and fungal culture on Sabouraud's dextrose agar and Dixon's agar. Of the otitis specimens, 63.7% showed typical Malassezia cells on cytological examination. In samples taken from the healthy ears of dogs with unilateral otitis, only 21.43% (P<0.05) showed evidence of Malassezia. M. pachydermatis was identified cytologically and culturally in 57.53% (P<0.05), 14.29% and 30.0% of samples from the ears of dogs with otitis, from the healthy ears of dogs with unilateral otitis and from the ears of healthy dogs with no otitis. In the group with otitis associated with M. pachydermatis, the poodle was the most common breed (39.29%; P<0.05), whereas in the group without otitis, the German Shepherd breed was prominent (although this observation was not statistically significant). In both groups, the majority of dogs with M. pachydermatis were aged between 1 and 3 years (P<0.05). The higher incidence of M. pachydermatis isolated from the ears of dogs with otitis externa suggests a putative pathogenic role of this yeast in this condition.

Clinical and microbiological profiles of ear infections in Osogbo, Nigeria

Despite the fact that discharging ears (DE) are one of the most common presentations to ear, nose and throat (ENT) clinics in the tropics, few reports have documented the aetiologic agents involved. The pathogenesis is therefore not fully understood and treatment remains controversial. We present in this report the microbiological characteristics of DE over a 3-year-period at the ENT clinic of Ladoke Akintola University Teaching Hospital, Osogbo, Southwest Nigeria.

Resistance of Pseudomonas to ciprofloxacin: implications for the treatment of malignant otitis externa

For fifteen years oral ciprofloxacin has been the standard treatment for malignant otitis externa, a sometimes fatal osteomyelitis of the skull base usually caused by Pseudomonas aeruginosa. Resistance to ciprofloxacin is developing. Over a 16-month period, we saw five cases where malignant otitis externa progressed, with the development of cranial nerve palsies in four cases, despite oral ciprofloxacin. Prolonged intravenous antibiotic therapy became necessary. One case was managed largely as an out-patient, but four patients spent many weeks in hospital. Only two cases had diabetes and this was monitored and controlled. Pseudomonas aeruginosa was isolated in four of the five cases, but antibiotic sensitivity to ciprofloxacin was not determined. In one case a later isolate was tested and found to be ciprofloxacin resistant. Progress was monitored by serial C-reactive protein (CRP) and white cell count. For diagnosis and assessing response to treatment we considered serial magnetic resonance imaging or computed tomography more useful than isotope bone scan. There must be a readiness to use intravenous antibiotics, as a response to ciprofloxacin can no longer be assumed. Bacterial isolates must be tested for sensitivity to antibiotics including ciprofloxacin, and further biopsy and culture are essential if treatment fails.

Otomycosis: subdermal growth in calcified mass

Reports on clear identification of fungi in subdermal tissue in chronic fungal external otitis are rare in recent years. Our patient was an immunocompetent adult male with an 8 year history of chronic otitis externa who presented with pustules on the external auditory canal (EAC) and necrosis and perforation of the tympanic membrane. Type I tympanoplasty was performed, but wound healing was delayed and swelling of the EAC occurred. Incision biopsy and staining (Gomori-Grocott and PAS) revealed fungal hyphae within small, calcified, subepidermal masses. A 3 month course of oral itraconazole was effective in healing the lesion. Calcification, a rarely reported finding in otomycosis, may represent a protective reaction against topical use of antifungal drugs.

Comparison of 4 fixation and staining methods for the cytologic evaluation of ear canals with clinical evidence of ceruminous otitis externa

BACKGROUND

Swab cytology of ear canals is one of the most useful and rapid methods to assess the presence of external ear infections. Smears are generally stained with rapid Romanowsky-type stains, with or without prior heat fixation.

OBJECTIVES

The aim of this study was to compare 4 different methods of fixation and staining of ear swab cytology samples from dogs.

METHODS

Eight dogs with otitis externa were selected from a dermatology referral population. A cotton swab was used to obtain ceruminous material from 12 ear canals. Four smears of each swab were prepared on glass slides (randomly identified as A, B, C, or D) and air-dried for cytologic examination. Samples marked A were stained with Dip Quick (Jorgensen Laboratories Inc, Loveland, CO, USA) after heat fixation; samples marked B were stained without heat fixation; samples marked C were heat-fixed and dipped only in the counterstain (the blue reagent) of Dip Quick; and samples marked D were dipped only in the counterstain, without heat fixation. Ten high-power fields (hpf; X100 oil immersion objective) in each slide were evaluated by 2 observers, and total numbers of keratinocytes, yeast, bacteria, and neutrophils were counted. Statistical comparison was performed using an ANOVA model applied after verifying the normal distribution of the data, and using nonparametric sign tests and Wilcoxon signed rank tests.

RESULTS

No statistically significant differences were observed in the numbers of keratinocytes, yeast, bacteria, or neutrophils among the 4 staining methods (P > .05), although significant interobserver differences were found.

CONCLUSION

We conclude that heat fixation does not improve the quality of ceruminous ear swab samples for cytologic evaluation, and propose a 1-step dip in the blue reagent alone as a rapid method of staining samples from canine ear canals.

In vitro activity of an ear rinse containing tromethamine, EDTA, and benzyl alcohol on bacterial pathogens from dogs with otitis

OBJECTIVE

To evaluate the in vitro activity of an ear rinse (ER) containing tromethamine, EDTA, and benzyl alcohol on bacterial pathogens from dogs with otitis.

SAMPLE POPULATION

Organisms were collected from ear swab specimens from the external and middle ear and included Staphylococcus spp (n = 11; Staphylococcus intermedius [7] and Staphylococcus spp [4]), Pseudomonas aeruginosa (5), Proteus spp (5), beta-hemolytic streptococcus (11), and 1 control strain of each organism.

PROCEDURES

3 test solutions were evaluated including EDTA, tromethamine, and benzyl alcohol (ER); EDTA and tromethamine (ER without benzyl alcohol [ER - BA]); and purified water. Ten-milliliter aliquots of each test solution were transferred into 36 tubes and inoculated with one of the organisms. Samples were retrieved from each tube at 0, 15, 30, 45, and 60 minutes, transferred to Petri dishes, mixed with soybean-casein digest agar, and incubated. After incubation, plates were examined for growth, and the number of colonies was expressed as CFU per milliliter.

RESULTS

ER significantly decreased bacterial growth in vitro of P aeruginosa and beta-hemolytic streptococcal organisms within 15 minutes, Proteus spp within 30 minutes, and Staphylococcus spp within 60 minutes. Comparatively, the presence of benzyl alcohol in ER significantly decreased bacterial growth of beta-hemolytic streptococcus and Proteus spp.

CONCLUSIONS AND CLINICAL RELEVANCE

On the basis of results of this study, future studies should be performed to evaluate the in vivo efficacy of ER alone as a treatment for otic infections caused by beta-hemolytic streptococcus, P aeruginosa, and Proteus spp and of ER combined with an antimicrobial agent for otic infections caused by Staphylococcus spp.

Value of hyperbaric oxygen in bacterial and fungal malignant external otitis treatment

Malignant external otitis (MEO) is an invasive, morbidity, even mortality, mainly pseudomonal infection of the external auditory canal, frequently involving the base of the skull, multiple cranial nerve and the meninges. In many cases conventional therapy has been prolonged, intensive and relatively ineffective, especially in infections other than bacterial (mainly fungal). We presented theoretical principles of hyperbaric oxygen (HBO) treatment in MEO, our own experience and others' experience in applying this treatment method. We treated eight patients with MEO applying pharmacotherapy, topical management, surgery in one case and also adjunct HBO. In six patients, infection was caused by Pseudomonas aeruginosa, in one by Staphylococcus sp. and in one by Aspergillus sp. Complete recovery was achieved in seven patients. In the patient with MEO caused by Aspergillus sp., intracranial complications developed and the patient died. Our experiences in employing HBO in bacterial-caused MEO have confirmed the role of HBO as a valuable, beneficial, supporting classical treatment method. Small number of patients with MEO, especially with non-bacterial infection, and unforeseen clinical course of disease make our experience difficult to objectivize.

Osteomyelitis of the ear canal caused by Staphylococcus lugdunensis

Osteomyelitis of the temporal bone caused by Staphylococcus lugdunensis has never been reported before. This infection was diagnosed in a 51-year-old diabetic man. S. lugdunensis is an unusually virulent coagulase negative staphylococcus and has been implicated in a variety of severe infections. Considering the serious morbidity and mortality associated with osteomyelitis and in particular with S. lugdunensis, special awareness and alertness are required when otitis externa, which predisposes to osteomyelitis, is refractory to treatment.

Tea tree oil: in vitro efficacy in otitis externa

Objective: The purpose of this study was to determine the susceptibility of organisms causing otitis externa (OE) to the essential oil of Melaleuca alternifolia, or tea tree oil (TTO).

Methods: Fifty-seven swabs were taken from the ears of 52 patients with OE for culture and sensitivity. A broth microdilution method was used to determine the minimum inhibitory concentration (MIC) of TTO for each organism.

Results: In 51 per cent of the swabs taken, pathogenic organisms were cultured. Of these cultures 71 per cent, both bacteria and yeast, were susceptible to TTO 2 per cent or less. The only organism showing resistance to TTO was Pseudomonas aeruginosa; however 25 per cent of these bacteria were sensitive.

Conclusion: Tea tree oil may have a role to play in the treatment of OE. However, more work needs to be done to enhance the anti-pseudomonal effect and to assess ototoxicity.

A group III steroid solution without antibiotic components: an effective cure for external otitis

The present study was undertaken to compare the clinical benefits of prescribing ear drops containing 0.05% solution of betamethasone dipropionate (BD), and ear drops containing hydrocortisone with oxytetracycline hydrochloride and polymyxin B (HCPB), for topical treatment of external otitis.

Fifty-one patients were enrolled in this open randomized, parallel-group, multicentre study,performed in eight different ENT departments. The patients were randomly assigned to one of thetwo treatment groups: BD (n= 26) and HCPB (n= 25). Only ENT specialists investigated the patients. Bacterial and fungal cultures were raised on days 1 and 11, using swabbedmaterial from ear canals. Twice daily the patients recorded their symptoms during the acute phase, using special diary cards.

BD proved a significantly more effective cure than HCPB during the acute phase of external otitis and afforded a lower relapse frequency during a six-month follow-up period. The patients of the BD group were significantly less troubled by itching (p <0.01) than those in the HCPB group. On day 11, at the end of the acute phase, growth of bacteria (p= 0.03) and fungi (p < 0.01) was less frequent in the BD group than inthe HCPB group. No serious adverse events occurred, and those minor events observed were comparable between the two groups.

Our conclusion is that the group III steroid solution, BD, cured the external otitismore effectively than did the HCPB solution, whether infected by bacteria or by fungi. No difference was evident regarding adverse effects. Furthermore, price favours a solution without any antibiotic component. In view of these observations, a group III steroid solution ought to be the preferred remedy for external otitis, whether infected or not.

Microbiology of cerumen in patients with recurrent otitis externa and cases with open mastoidectomy cavities

This study investigated the common flora of human cerumen in patients with recurrent otitis externa, and subjects who had been operated on and had an open mastoidectomy cavity from chronic otitis media.

Cerumen samples were collected from three groups; group A (n = 20) consisted of patients with recurrent otitis externa, group B (n = 20) consisted of patients with an open cavity and group C (n = 30) consisted of healthy subjects.

The mean of the microbial count was 3.4 × 104 in group A, 3.08 × 104 in group B and 2.48 × 104 in group C. The most commonly isolated microorganism from the three groups was Staphylococcus epidermidis. No growth was observed in five cases (25 per cent) in group A and in three cases (10 per cent) in group C. In groupB antimicrobial growth was observed in all samples. In 46 (65 per cent) of the cerumen samples,the isolates were monomicrobial and 24 (35 per cent) of the cerumen samples were polymicrobial. The isolates were polymicrobial in 65 per cent of group A, 20 per cent in group B and 23.3 per cent in group C.

In the process of investigating the microbial flora of cerumen in all the three groups, microbial growth was observed from all the samples from patients with an open cavity, unlike the other groups, and it was determined that the group with recurrent external otitis had the most abundant microbial flora.