Diagnosis

Multiple sclerosis is characterized by recurring neurologic episodes that are due to multiple lesions (injured areas) in different locations in the central nervous system. The diagnostic challenges in multiple sclerosis are two-fold:

Making an initial diagnosis as early as possible in order to slow down the disease progression. Most patients first seek medical help after an initial inflammatory event (known as a clinically isolated syndrome) originating from demyelination in the eye, the spinal cord, or the brain. About 30% of these individuals will develop progressive MS within the year. At this time, however, experts cannot predict who among these patients are at highest risk for rapid progression.
Predicting the severity of the disease. Once MS has been diagnosed, the pattern of the disease is uncertain. It can be very benign to rapidly progressive and severe. Magnetic resonance imaging (MRI) is able to detect lesions in the brain indicating MS. But, the severity of the disease does not appear related to the number of lesions, the rate of their appearance, or their location. Researchers are hoping to identify some biologic marker, possibly certain antibodies, that will enable doctors to accurately determine the onset and severity of the problem once a diagnosis has been made.

The McDonald Criteria. There is no single test that can accurately diagnose MS and a number of other conditions may mimic its symptoms. Some doctors use a set of factors, called the McDonald criteria, for diagnosing multiple sclerosis in early stages. The criteria include the presence of specific symptoms, spinal fluid evaluation, and magnetic resonance imaging techniques for detecting lesions within the central nervous system and tracking them over time. The criteria show high reliability in identifying MS in patients with a variety of disease stages or states, including having only one episode, having a typical relapsing-remitting course, or having a slow insidious progression without clear attacks or remissions. Depending on the MRI and other findings, the patient is then categorized as having MS, possible MS, or no MS.