[A relapse of multiple sclerosis manifesting as acute delirium]

Psychotic symptoms are infrequent in multiple sclerosis (MS) and their relationship to cerebral lesions has not been clearly documented. The case of a 58 year old woman with secondary progressive MS is presented. She had acute delirium with persecutory delusions associated to paresis of her left leg. Magnetic resonance imaging of the brain disclosed an active lesion in the left hippocampus. The patient was treated with risperidone and megadoses of methylprednisolone, with dramatic improvement. Clinical and radiological data in this patient suggest that psychotic disorders can be symptomatic of a relapse in MS and, therefore, susceptible to be treated with steroids.