MS: Causes, incidence and risk factors
Multiple sclerosis is an autoimmune disease that affects the central nervous system (the brain and spinal cord). Multiple sclerosis (MS) usually affects woman more than men. The disorder most commonly begins between ages 20 and 40, but can strike at any age.
The exact cause is not known, but MS is believed to result from damage to the myelin sheath, the protective material which surrounds nerve cells. It is a progressive disease, meaning the damage gets worse over time. Inflammation destroys the myelin, leaving multiple areas of scar tissue (sclerosis). The inflammation occurs when the body's own immune cells attack the nervous system.
The inflammation causes nerve impulses to slow down or become blocked, leading to the symptoms of MS. Repeated episodes, or flare ups, of inflammation can occur along any area of the brain and spinal cord.
Symptoms vary because the location and extent of each attack varies. Usually episodes that last days, weeks, or months alternate with times of reduced or no symptoms (remission).
Recurrence (relapse) is common although non-stop progression without periods of remission may also occur.
Researchers are not sure what triggers an attack. Patients with MS typically have a higher number of immune cells than a healthy person, which suggests that an immune response might play a role. The most common theories point to a virus or genetic defect, or a combination of both. There also appears to be a genetic link to the disease. MS is more likely to occur in northern Europe, the northern United States, southern Australia, and New Zealand than in other areas. Geographic studies indicate there may be an environmental factor involved.
People with a family history of MS and those who live in a geographical area with a higher incidence rate for MS have a higher risk of the disease.
Symptoms
- weakness of one or more extremities
- paralysis of one or more extremities
- tremor of one or more extremities
- muscle spasticity (uncontrollable spasm of muscle groups)
- muscle atrophy
- movement, dysfunctional - slowly progressive; beginning in the legs
- numbness or abnormal sensation in any area
- tingling
- facial pain
- extremity pain
- loss of vision -- usually affects one eye at a time
- double vision
- eye discomfort
- uncontrollable rapid eye movements
- eye symptoms worsen on movement of the eyes
- decreased coordination
- loss of balance
- decreased ability to control small or intricate movements
- walking/gait abnormalities
- muscle spasms (especially in the legs)
- dizziness
- vertigo
- urinary hesitancy, difficult to begin urinating
- strong urge to urinate (urinary urgency)
- frequent need to urinate (urinary frequency)
- incontinence (leakage of urine, loss of control over urination)
- decreased memory
- decreased spontaneity
- decreased judgment
- loss of ability to think abstractly
- loss of ability to generalize
- depression
- decreased attention span
- slurred speech
- difficulty speaking or understanding speech
- fatigue, tired easily
- constipation
- hearing loss
- positive Babinski's reflex
