The radionuclide diagnosis, evaluation and follow-up of malignant external otitis (MEO). The value of immediate blood pool scanning

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.

Synchronous Occurrence of Bilateral Malignant Otitis Externa: Report of a Rare Case

Malignant otitis externa (MOE) is a rare and potentially life-threatening disease of the ear and temporal bone. Bilateral simultaneous MOE is extremely rare. Due to bilaterally symmetrical facial nerve palsy, it can easily be missed at the initial presentation, causing delay in management. Here, we report a case of bilateral MOE managed aggressively with regular ear toileting, ear packing with a ribbon gauze soaked with topical antimicrobials, and long-term intravenous and oral antibiotics. The patient showed good improvement in pain control, facial nerve status, and ear findings.

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.

Necrotizing otitis externa: 19 cases' report

Necrotizing otitis externa is an uncommon but severe infectious disease of the external auditory canal. Patients at risk are those immunodepressed or having diabetes. The causal germ is often Pseudomonas aeruginosa. Over a period of 10 years (1997-2006), we treated 19 patients: 94.7% had diabetes (insulin dependent in 6 cases). The causal germ was P. aeruginosa in 59% of cases. The pretherapeutic work-up included a computed tomography and a scintigraphy practiced in order to confirm diagnosis and assess the extension. Medical treatment was based on a parenteral antibiotic therapy using a third-generation cephalosporin and a fluoroquinolones. Local treatment of the auditory canal including cleaning and application of antimicrobial agents was performed in all the cases. Surgical debridement of soft tissue and infected bone was performed in one patient who did not respond to medical management. Repeated scintigraphies with gallium were used to follow the course under treatment in only three cases. We had a 89.4% cure rate with only three cases of recurrence. We reviewed the data in the literature on necrotizing otitis externa and present the important diagnostic, imaging, and therapeutic aspects of the disease.

The changing face of malignant (necrotising) external otitis: clinical, radiological, and anatomic correlations

Malignant (necrotising) external otitis is an invasive infection of the external auditory canal. Although elderly patients with diabetes remain the population most commonly affected, immunosuppressed individuals (eg, from HIV infection, chemotherapy, etc) are also susceptible to malignant external otitis. Pseudomonas aeruginosa is isolated from the aural drainage in more than 90% of cases. The pathophysiology is incompletely understood although aural water exposure (eg, irrigation for cerumen impaction) has been reported as a potential iatrogenic factor. The typical patient presents with exquisitely painful otorrhoea. If untreated, cranial neuropathies (most commonly of the facial nerve) can develop due to subtemporal extension of the infection. The diagnosis of malignant external otitis is based on a combination of clinical findings, an increased erythrocyte sedimentation rate, and radiographic evidence of soft tissue with or without bone erosion in the external canal and infratemporal fossa. Treatment consists of prolonged administration (6-8 weeks) of an antipseudomonal agent (typically an orally administered quinolone). With the introduction and widespread use of both oral and topical quinolones, there are reports of less severe presentation of malignant external otitis and even the emergence of ciprofloxacin resistance. Reservation of systemic quinolones for the treatment of invasive ear infections is recommended.

Skull base osteomyelitis interpreted as malignancy

Lesions in the skull base may present difficulties in diagnosis primarily because the access needs to be invasive and one has to rely on imaging that may still be misleading. The case presented here illustrates this example in that the patient had abnormalities on computed tomography (CT) and magnetic resonance image (MRI) scans quite convincing of malignancy but which with time proved, essentially through clinical judgment, to be skull base osteomyelitis secondary to malignant external otitis (OME).

Relapsing malignant otitis externa successfully treated with ciprofloxacin

Two cases are presented, both patients with advanced relapsing malignant otitis externa. The antibiotic ciprofloxacin has strong anti-pseudomonal activity. It was given orally for six months to both patients, following administration of the traditional parenteral antibiotic courses, and in each case the disease has been extinguished. We therefore recommend that the management of patients shown to have malignant otitis externa should include strict diabetic control, regular local aural toilet, gentamicin ear drops and a six week course of parenteral antipseudomonal antibiotic agents (usually gentamicin and azlocillin) together with metronidazole to cover any anaerobic element in the infection. This regimen should be followed by a six month course of oral ciprofloxacin (750 mg b.d.). Indium scans should be used to monitor recovery. We believe that this regimen can significantly reduce the morbidity and mortality of patients suffering from malignant otitis externa with cranial nerve involvement.

Malignant external otitis: insights into pathogenesis, clinical manifestations, diagnosis, and therapy

Malignant external otitis is an infection of the external ear canal, mastoid, and base of the skull caused by Pseudomonas aeruginosa. The condition occurs primarily in elderly patients with diabetes mellitus. Current theories on pathogenesis and anatomic correlations are reviewed. Severe, unrelenting otalgia and persistent otorrhea are the symptomatic hallmarks of the disease, whereas an elevated erythrocyte sedimentation rate is the only distinctive laboratory abnormality. Iatrogenic causes such as administration of broad-spectrum antibiotics and aural irrigation may play a predisposing role in high-risk populations. The disease can result in cranial polyneuropathies (with facial nerve [VII] paralysis being the most common) and death. The mainstay of treatment is administration of antipseudomonal antibiotics for four to eight weeks. Recurrence is common, and mortality remains at about 20 percent despite antibiotic therapy. Given the increasing longevity of diabetic patients, the frequency of this disease is increasing. Internists, family practitioners, and ambulatory care physicians must now be cognizant of the presenting symptoms, while infectious disease specialists and otolaryngologists need to be appraised of strides in diagnosis and therapy. The role of surgery should be minimized. Use of new diagnostic radiologic modalities and new antipseudomonal antibiotics discussed in this review should lead to improved outcome.

Necrotizing external otitis treated with ciprofloxacin. A case report

Necrotizing (malignant) external otitis is a severe infection caused by Pseudomonas aeruginosa which occurs mainly in elderly diabetics or in immuno-depressed patients (Chandler, 1968). The management of this condition requires the association between an aminoglycoside antibiotic and an antipseudomonal beta-lactamic, given parenterally during a 4 to 6 week period. Sometimes it is necessary to continue the therapy for months until there is no evidence of residual disease (Strauss et al., 1982). Ciprofloxacin is a quinolone with antipseudomonal activity which can be taken orally, and it is a useful alternative to the current treatment. The authors report a case of necrotizing external otitis which was successfully treated with ciprofloxacin.