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Multiple Sclerosis (MS) FAQs (cont.)

What causes multiple sclerosis?

White blood cells called T cells, which fight disease and infection, instead attack myelin, the fatty substance that surrounds and protects the nerves of the central nervous system. This attack damages the protective myelin sheath and either partially or completely strips the myelin off the nerve fibers (see Multimedia file 2). Because the myelin is supposed to help speed and direct the transmission of impulses along nerve cells, whenever any part of the myelin sheath is damaged, the nerve impulses are distorted. The messages the nerves try to send are delayed and usually misinterpreted by the brain, if the messages get through at all. This interruption of messages is what causes multiple sclerosis (MS) symptoms. Often, the T cells also damage the nerve fibers themselves, causing increased MS symptoms and increased disability over time. (See Myelin and the Central Nervous System.)

It is important for patients to realize that the immune system is not underactive in MS and that it does not predispose them to infections. Rather, the immune system in MS is overreactive to certain environmental agents and responds irregularly by attacking the central nervous system.

What are the symptoms of multiple sclerosis?

Symptoms of multiple sclerosis (MS) that appear depend on which part of the central nervous system is affected and what the job of the damaged nerve is. Symptoms can be mild, moderate, or severe.

Symptoms include the following:

  • Visual changes, including blurred, patchy or hazy vision, and loss of color perception, which may be accompanied by eye pain (Double vision may occur if the nerve pathways in charge of eye movements are affected.)
  • Fatigue, tiredness, and lack of energy
  • Numbness
  • Muscle tightness
  • Dizziness, imbalance, incoordination, and vertigo
  • Bladder and bowel dysfunction
  • Facial pain
  • Slurred speech
  • Difficulty with walking and fine motor skills
  • Mood swings
  • Memory loss

People with MS may have worsening of symptoms after taking a hot shower or bath, or being outside in hot weather for prolonged periods.

Symptoms that appear for days or weeks then disappear may be an early indication of MS.

Symptoms can come and go, appear in various combinations, and be mild to severe at different times.

Times when MS symptoms are active are called attacks or relapses. Times when symptoms are not present are called remissions. Most people with MS have days or weeks of relapses followed by months or years of remissions.

Medically Reviewed by a Doctor on 4/22/2016
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