Fungal malignant external otitis.

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.

Animal model of cochlear third window in the scala vestibuli or scala tympani.

HYPOTHESIS: The auditory impact of a cochlear third window differs by its location in the scala vestibuli or scala tympani. BACKGROUND: Pathologic third window has been investigated primarily in the vestibular apparatus of animals and humans. Dehiscence of the superior semicircular canal is the clinical model. METHODS: Fat sand rats (n = 11) have a unique inner-ear anatomy that allows easy surgical access. A window was drilled in the bony labyrinth over the scala vestibuli in 1 group (12 ears) and over the scala tympani in another (7 ears) while preserving the membranous labyrinth. Auditory brain stem responses to high- and low-frequency stimuli delivered by air and bone conduction were recorded before and after the procedure. RESULTS: Scala vestibuli group: preoperative air-conduction thresholds to clicks and tone-bursts averaged 8.3 and 9.6 dB, respectively, and bone-conduction thresholds, 4.6 and 3.3 dB, respectively; after fenestration, air-conduction thresholds averaged 40.4 and 41.8 dB, respectively, and bone-conduction thresholds, -1 and 5.6 dB, respectively. Scala tympani group: preoperative air-conduction thresholds to clicks and tone-bursts averaged 8.6 dB each, and bone-conduction thresholds, 7.9 dB and 7.1 dB, respectively; after fenestration, air-conduction thresholds averaged 11.4 and 9.3 dB, respectively, and bone-conduction thresholds, 9.3 and 4.2 dB, respectively. The changes in air- (p = 0.0001) and bone-conduction (p = 0.04) thresholds were statistically significant only in the scala vestibuli group. CONCLUSION: The presence of a cochlear third window over the scala vestibuli, but not over the scala tympani, causes a significant increase in air-conduction auditory thresholds. These results agree with the theoretic model and clinical findings and contribute to our understanding of vestibular dehiscence.