Skull base osteomyelitis: incidence of resistance, morbidity, and treatment strategy.

Objectives/hypothesis: The pathogeny of osteomyelitis of the skull base has evolved over time with the emergence of ciprofloxacin-resistant Pseudomonas strains and significant fungal infections, both of which seem to bring a higher morbidity. The aims of this study were 1) to document the incidence of ciprofloxacin-resistant Pseudomonas aeruginosa over the past 7 years; 2) to assess morbidity by a radiologic score, the occurrence of cranial nerve palsies, and the duration of the hospital stay, according to the pathogenesis; and 3) to propose a treatment strategy.

Study Design: Retrospective chart review of necrotizing external otitis cases from 2004 to 2011. The setting was the Department of ENT Surgery, Lariboisière Hospital, Paris.

Methods: Thirty-one patients were included. Radiological scores were assessed based on the initial computed tomography scans or magnetic resonance imaging, which specified the anatomical territory involved. Nerve palsies, the duration of hospitalization, and the radiological scores were analyzed with regard to the pathogen.

Results: Twenty-eight patients had a bacterial disease. Of the 20 strains of P. aeruginosa identified, five (25%) were ciprofloxacin-resistant P. aeruginosa. Three patients (10%) had a fungal infection due to Aspergillus flavus. Nerve palsies, radiological scores, and hospitalization durations were significantly higher for patients with resistant strains and A. flavus.

Conclusions: In our series, the prevalence of ciprofloxacin-resistant Pseudomonas strains increased over time. Along with fungal infections, they formed a group with a higher morbidity than that of ciprofloxacin-sensitive Pseudomonas infections that furthermore did not respond to oral outpatient treatment. This is why pathogen identification using biopsies is sometimes required to start a prolonged treatment.