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Malignant external otitis: review and personal experience
L Amorosa1, G C Modugno, A Pirodda
1Department of Otorhinolaryngology, University of Bologna, Italy.
Abstract:
Malignant external otitis (MEO) is an infrequent but severe infective disorder, generally due to Pseudomonas aeruginosa, which most often affects elderly diabetics patients. The clinical features rarely permit exact diagnosis of MEO to be made promptly, and initially at least they are difficult to distinguish from those of external otitis. This explains the frequent delay in diagnosis with respect to the onset of symptoms. Physical examination almost always reveals the presence of aspecific granulation tissue in the external auditory canal, while the most common laboratory finding is raised erythrocyte sedimentation rate (ESR). Imaging has great diagnostic relevance: CT and MRI are very useful for spatial resolution, while radionuclide scanning and, in our experience, SPECT are superior for detecting early osteitis and monitoring response to therapy. We present an extensive review of the literature and our personal experience. In particular, we stress the relevance of immunological study of MEO patients: all our 4 patients had defective immune defences. As regards therapy, like other authors we underline the fundamental importance of long-term antibiotic treatment. The availability of quinolones and latest generation cephalosporins has greatly simplified the choice of antibiotic treatment, although clinicians should be aware of the possibility of drug-resistant bacterial strains.
Insights
Malignant external otitis (MEO), a severe Pseudomonas aeruginosa infection, often affects elderly diabetics. Prompt diagnosis is challenging, but imaging and immune status are key for effective, long-term antibiotic therapy.
Area of Science:
- Infectious Diseases
- Otolaryngology
- Diabetology
Background:
- Malignant external otitis (MEO) is a severe infection, typically caused by Pseudomonas aeruginosa, predominantly affecting elderly patients with diabetes.
- Early diagnosis of MEO is often delayed due to non-specific initial symptoms that mimic simple external otitis.
- Identifying risk factors such as diabetes and compromised immune defenses is crucial for MEO management.
Observation:
- Physical examination frequently reveals non-specific granulation tissue in the external auditory canal.
- Elevated erythrocyte sedimentation rate (ESR) is a common laboratory finding in MEO patients.
- Imaging modalities including CT, MRI, radionuclide scanning, and SPECT are vital for diagnosis and monitoring treatment response, particularly for detecting early osteitis.
Findings:
- SPECT imaging demonstrates superiority in detecting early osteitis and assessing therapeutic response.
- Immunological evaluation revealed defective immune defenses in all reviewed MEO patients.
- Long-term antibiotic treatment is fundamental for managing MEO, with quinolones and newer cephalosporins offering effective options.
Implications:
- Early and accurate diagnosis of MEO can be improved through a combination of clinical suspicion, imaging, and immunological assessment.
- Understanding the role of immune status in MEO pathogenesis may lead to targeted therapeutic strategies.
- Awareness of potential drug-resistant bacterial strains is essential when selecting long-term antibiotic regimens for MEO.