[Optic neuritis. A common first manifestation of multiple sclerosis].

Acute monosymptomatic optic neuritis (ON) may be regarded as a specific disease entity, or ON may be viewed as a first manifestation of multiple sclerosis (MS) representing one end of a continuum with fully developed clinically definite MS at the other end. To clarify this, the literature is reviewed, and the relationship between ON and MS is exemplified by examination of a cohort of 50 untreated representative patients with relevant paraclinical tests at onset of monosymptomatic ON. MRI, neurophysiological examinations and CSF analyses are supplementary methods, which together provide evidence that monosymptomatic ON is usually an early manifestation of MS, both being associated with the HLA tissue type DR15. The frequent finding of unenhanced lesions on MRI probably signify that the disease process may start long before the symptoms of ON. CSF may not be representative of the pathological processes in the CNS. Bilateral ON is not particularly liable to herald MS. More attention should be paid to subtle visual disturbances, which may indicate a new attack. It is important that more sensitive evaluations than merely assessing visual acuity be performed in these patients.