Multiple sclerosis is a chronic, progressive, degenerative disorder that affects the central nervous system. An environmental factor or virus triggers chronic inflammation. The inflammatory process causes disseminated demyelination of nerve fibers of the brain and spinal cord.
Multiple sclerosis causes motor issues such as trembling and weakness of the limbs, trunk, or head. Weakness may progress to paralysis. Weakness is caused by slowed transmission of nerve impulses related to inflammatory damage to the myelin sheath. Since chronic inflammation may destroy the myelin's ability to regenerate, the underlying axon may be damaged and cause permanent loss of nerve function resulting in paralysis.
Chronic inflammation may develop glial scar tissue and form hard, sclerotic plaques. The plaques may form throughout the white matter of the central nervous systems and affect the cerebellum. Nystagmus, or involuntary eye movement, is a symptom of cerebellar damage. Additional cerebellar signs include scanning speech, ataxia, dysarthria, and dysphagia.
A significant percentage of patients with multiple sclerosis experience fatigue that may affect their ability to complete activities of daily living. Fatigue may be worsened by heat, humidity, and medication side effects. Drug therapy indicated to treat fatigue include amantadine (Symmetrel), pemoline (Cylert), modafinil (Provigil), and methylphenidate (Ritalin).
Paresthesias is described as a tingling or numbing sensation and is a common symptom related to the demyelination of nerve fibers. The patient may experience sensory abnormalities such as tingling and pain.
The patient with multiple sclerosis may experience spasticity in muscles chronically affected by the demyelination of nerve fibers. Muscle relaxants are indicated to help treat spasticity.
If the sclerotic plaque caused by chronic inflammation is located in areas of the central nervous system that control elimination, the patient will experience bowel and bladder dysfunction. The patient with multiple sclerosis may experience spastic or uninhibited bladder accompanied by urinary urgency and frequency. A lesion in the reflex arc controlling bladder function will cause flaccid or hypotonic bladder. Since they lack the sensation or desire to void, patients with flaccid bladders develop a large capacity for urine. Anticholinergics may be used to treat bladder dysfunction.
Patients with MS may develop optic neuritis. By recording electrical activity, evoked potential testing can diagnose visual abnormalities such as optic neuritis.
Multiple sclerosis commonly affects adults between 20 and 50 years of age. Adult females are two to three times more affected than adult males. Multiple sclerosis may also occur in young teens and much older adults.
Individuals with MS often experience symptom relapse and remission. Degeneration of the myelin sheath causes symptoms such as weakness. However, myelin may regenerate and reverse symptoms. The remission of symptoms may be followed by a relapse of symptoms, as the inflammatory process is activated and causes damage to the myelin sheath. Repeated exacerbations progresses to deterioration of neurologic function.
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