When does multiple sclerosis start? Three case reports and a review of the literature

When does multiple sclerosis start? Multiple sclerosis (MS) is a major cause of disability in young adults. Its pathogenesis is not fully understood, although a large body of evidence suggests an autoimmune pattern. Autoreactive immune cells cross the blood-brain barrier to attack myelin and axons, thus leading to MS lesions. Considering the uncertainty concerning the mechanisms, however, it is hardly surprising that it is still not possible to pinpoint exactly when the disease starts. Yet, the question is of major importance for both patients and physicians. Faced with the impossibility of detecting the actual time of disease onset, the scientific community has nonetheless made great efforts to diagnose the disease as early as possible. In 1983, Poser defined relapsing-remitting MS as a chronic disease with at least two relapses. Further criteria (McDonald) allowed even earlier diagnosis. In the present review, which also includes three case reports, the earliest possible timepoint for making the MS diagnosis is discussed.