Multiple Sclerosis

Multiple sclerosis is a chronic, often disabling disease of the central nervous system in which myelin and axonal injury leads to various symptoms such as blurred vision, weakness and numbness, and even paralysis or loss of vision. Most people with MS are diagnosed between the ages of 20 and 40 but the unpredictable physical and emotional effects can be life-long. The progress, severity and specific symptoms of MS in any one person cannot yet be predicted. Approximately 400,000 people in the United States (and 2 million world-wide) have MS with 200 people being diagnosed weekly.

Myelin is made by oligodendrocytes and is an insulating-like substance necessary for the rapid conduction of electrical impulses in the nervous system. In the absence of myelin, electrical impulses along axons are slowed or stopped and the normal communication between neurons, muscle, retina, etc. is compromised. The cause of the disease is unknown but myelin and oligodendrocytes are likely the primary target, and axons appear to be a secondary target. The mechanism by which oligodendrocytes, myelin, and axons are injured is also unknown but leading considerations are inflammation, autoimmunity, and primary degeneration of the oligodendrocytes.

The effects of MS on the brain were first described in the 1830's and it was first identified as a distinct clinical entity in the 1860's. Even though it has been almost 140 years since its "discovery", we still do not know the cause of MS. Since we do not know the cause of MS, nor can we conclusively diagnose it, it is possible that MS is actually multiple diseases.

A diagnosis of MS is an uncertain judgement. To diagnose MS, the neurologist usually requires clinical evidence that the neurological deficits indicate involvement of at least two different areas (functional systems) of the central nervous system, with documented neurological signs occurring at two separate and distinct time periods; and all other possible neurologic causes must have been eliminated. The only concrete symptom that is common to all MS diagnoses (by definition) is demyelenation in the central nervous system.

Multiple Sclerosis is essentially a clinically determined diagnosis of exclusion. There are no tests which are specific for MS, and no single test is 100% conclusive. Conventional MRIs only image some lesions (macroscopic ones), which are non-specific as to cause and do not fully account for MS. Therefore, several tests and procedures are needed to eliminate all other possible causes and firmly establish a diagnosis of MS. They include the following:

• Diagnostic Categories (definite, probable, possible MS)
• Medical History
• Neurological Examination
• Evoked Potentials
• Magnetic Resonance Imaging
• Lumbar Puncture (Spinal Tap)