Place des explorations isotopiques dans les otites externes nécrosantes

BackgroundThe necrotizing otitis externa (NOE) is potentially lethal which mainly occurs on the most among the elderly and diabetic. The aim of our study was to evaluate the contribution of isotopic explorations in diagnosis, staging and monitoring of the NOE.MethodsOur retrospective study was about 50 patients with a strong suspicion of NOE who benefited a bone and/or gallium scintigraphy.ResultsOur population was composed of 38 men and 12 women with mean age of 68 years. All patients were diabetic. The most common complaint was otalgia (98% of cases). The sensitivity of computed tomography (CT) which was performed in 84% of cases was 66.6% of cases. Bone scintigraphy (BS) was performed in all patients showing increased uptake in the temporal region in 90% of cases. An extension to surrounding structures was objectified in 26% of cases. Follow-up Ga 67 SPECT was performed in 56% of cases, demonstrated increased uptake at the temporal region in 43% of cases. The statistical study showed that only the presence of an extended tympanic lysis on CT was statistically significant to the positivity of BS (P = 0.036). No statistically significant correlation was found between all other CT abnormalities, clinical and biological signs and the positivity of bone scintigraphy.ConclusionIsotopic explorations were a great contribution in the management of the NOE. At the initial phase, the BS allowed to confirm very early an existence of osteomyelitis of the skull base. During the follow-up, the gallium-67 scan allowed the following of the evolution of infectious process.