[Multiple sclerosis--certain clinical and diagnostic problems]

The diagnosis of MS is based exclusively on clinical examination disclosing at least two focal lesions, repeatedly occurring recurrences and ruling out of other causes. This is the generally accepted principle based on the diagnostic criteria of Poser. The presence of the lesions can be demonstrated in clinical examinations by magnetic resonance imaging /MRI/ or the study of evoked potentials /EP/ which detect these changes in about 90% of cases of clinically certain MS. In 10% of cases the results are negative--but can this exclude MS? It happens also that MRI or EP carried out for another reason demonstrate the presence of such lesions--is it MS in such cases? The diagnosis of SM is supported by age below 40 years and the presence of at least four focal lesions in the white matter of the hemispheres. After the age of 50 years such lesions can be the consequences of vascular disease. Contrast administration makes possible the detection of new foci and their differentiation from the old ones. In 65-85% of cases the initial phase is marked by remitting course with more or less evident worsening after each exacerbation. Out of them, in 40-70% of cases the remitting course changes to secondary progressing course. In only 10% of cases the course is progressing from the beginning. The prognosis is better if the disease begins with optic nerve involvement and is worse if pyramidal or cerebellar signs appear first. CSF examination is less important than MRI or EP. In biochemical tests no sure markers of the disease are found. In the treatment of acute exacerbations steroids are still most effective. In clinically confirmed MS interferon beta given in the first 2 years is effective in 30% of cases.