[Therapeutic indications for acute episodes of multiple sclerosis].

The natural history of multiple sclerosis (MS) exacerbations is characterized by a poor outcome in about 70 p. cent of cases. By contrast, the outcome of a first episode of acute optic neuritis (ON) is usually good. However the disability associated with MS bouts and ON requires the use of a specific treatment. Nine randomized controlled clinical trials against placebo performed exclusively for MS exacerbations or acute ON were identified. Corticosteroids or ACTH produced a significant improvement in disability or vision at 30 days and shortened the duration of exacerbations. Longer follow-up clinical trials performed in MS exacerbation were not able to clearly demonstrate a significant effect. In acute ON clinical trials the long term visual outcome was not significantly different after steroid treatment than after placebo but this outcome is usually good. There is some evidence that high doses of intravenous methylprednisolone delay the occurrence of the next relapse, and have a dose-dependent effect on the rate of new lesion formation. There is no convincing evidence of the effectiveness of oral steroids in MS exacerbations but this treatment is associated with an increase relapse rate in ON. Side effects with intravenous methylprednisolone are less severe than with oral mega doses or ACTH.