Overview of Multiple Sclerosis

Course
MS is widely regarded as an autoimmune disease, generally characterized by periodic relapses or exacerbations and progressive neurological deterioration. The disease usually follows one of four courses (see Figures 1–4). Most patients usually present with a relapsing-remitting pattern, and according to a Mayo Clinic study, enter the secondary progressive phase five to 25 years later. Age at onset and gender are statistically related to the long-term course of the disease – female gender and younger age at onset often confer a more favorable prognosis. It is important to note that a patient living with MS for 20 or 30 years may experience substantial disability even if the progress is slow, and in the first 10 or 15 years he or she is relatively mildly affected. Late onset, i.e. over 55 years, particularly among males, is associated with a progressive course of the disease.

Relapsing-remitting MS (RRMS) is the most common form of the disease. It is characterized by clearly defined acute attacks with full recovery (see Figure 1a) or with residual deficit upon recovery (see Figure 1b). Periods between disease relapses are characterized by a lack of disease progression. Approximately 85% of people with MS begin with a relapsing-remitting course.

Secondary progressive MS (SPMS) begins with an initial relapsing-remitting disease course, followed by progression of disability (see Figure 2a) that may include occasional relapses and minor remissions and plateaus (see Figure 2b).Typically, SPMS is characterized by less recovery following attacks, persistently worsening functioning during and between attacks, and/or fewer and fewer attacks – or none at all – accompanied by progressive disability. Of the 85% who start with RRMS, more than 50% will develop SPMS within 10 years. Ninety per cent of those with RRMS will develop SPMS within 25 years.

Primary progressive MS (PPMS) is characterized by progression of disability from onset, without plateaus or remissions (see Figure 3a) or with occasional plateaus and temporary minor improvements (see Figure 3b). Ten per cent of people with MS are diagnosed with PPMS, although the diagnosis usually needs to be made after the fact – when the person has been living for a period of time with progressive disability, but not acute attacks.

Progressive relapsing MS (PRMS), which is the least common disease course, shows progression of disability from onset but with clear acute relapses, with (see Figure 4a) or without (see Figure 4b) full recovery. Approximately 5% of people with MS appear to have PRMS at diagnosis.Symptoms
Symptoms of MS vary in severity and duration, and manifest in differing combinations, depending on the area of the nervous system affected. Complete or partial remission, especially in the early stages of the disease, occurs in approximately 70% of MS patients. Patients often present with visual changes indicative of optic neuritis, sensory disturbances or focal muscle weakness.

Symptoms of MS include:

• visual changes;
• focal muscle weakness;
• fatigue;
• lidepression;
• bowel/bladder/sexual dysfunction;
• gait problems/spasticity;
• paresthesias;
• heat intolerance;
• dysarthria/scanning speech/dysphagia;
• Lhermitte’s sign;
• neuritic pain;
• vertigo/ataxia;
• cognitive dysfunction; and
• tremor/incoordination.