Risks of developing an otogenic intracranial abscess.

One-and-a-half per cent of adults have active chronic otitis media and its management to prevent complications is a considerable workload. The risks of developing these complications is relatively unknown but because of its mortality, intracranial abscess is the most relevant. A 10-year review of all otogenic intracranial absesses in Scotland was carried out. A 15 per cent allowance was made for missing records. The annual risk in an adult with active chronic otitis media of developing an abscess is about one in 10,000 but its development is three times more likely in males. This risk might appear low but the lifetime expectancy of an individual aged 30 years with active chronic otitis media developing an abscess is one in 200. However, as yet, there is no evidence that surgery reduces this risk. Unfortunately, because of the duration of follow-up needed and the size of the sample required, scientific evidence would be difficult to obtain. However, 5 per cent of abscesses currently occur in the immediate post-operative period following mastoid surgery.