Key issues in the diagnosis and treatment of multiple sclerosis

Understanding of the etiology and pathogenesis of MS has improved significantly in recent years. In addition, important developments have occurred in the diagnosis and treatment of this disease. This review provides a concise, up-to-date overview of key issues relating to MS and its management. The review is divided into four main sections. 1. A description of MS, covering symptoms and signs, natural history, epidemiology, etiology, and pathology and pathogenesis. 2. A critical analysis of the revised diagnostic criteria for MS that have recently been published by McDonald et al.1 3. A review of the key clinical studies that have been carried out with disease-modifying drugs for MS. 4. A discussion of the use of MRI as a surrogate measure in MS treatment trials, with commentaries on the specific MRI-oriented publications related to the disease-modifying therapies. ### Definition. MS is a chronic disease of the CNS, characterized by discrete areas of demyelination and axon injury associated with inflammatory activity. A key defining feature of MS is that lesions are disseminated in both space and time, i.e., they occur at more than one site and develop on more than one occasion. Additional information on the pathology of MS is provided below. Clinically, MS symptoms emerge between the ages of 20 and 40 years in approximately 70% of patients,2,3⇓ although changes visible on MRI are much more common than clinical activity and may well precede the latter.4-6⇓⇓ ### Symptoms and signs. Because MS lesions can occur in many different parts of the CNS, they can cause a wide variety of symptoms and signs. An exhaustive list of clinical findings seen in MS clinics at the Universities of British Columbia and Western Ontario, Canada, is provided by Paty and Ebers,7 together with estimates of the frequencies of each finding at onset and at any time. According to …