The exact cause of Guillain-Barre syndrome is unknown. In about 60 percent of cases, an infection affecting either the lungs or the digestive tract precedes the disorder. Recent surgery, immunization and pregnancy have also been associated with Guillain-Barre syndrome. But scientists don't know why such an infection can lead to Guillain-Barre syndrome for some people and not for others. Many cases appear to occur without any triggers.

In Guillain-Barre syndrome, your immune system — which usually attacks only foreign material and invading organisms — begins attacking the nerves that carry signals to your brain. In the most common form of Guillain-Barre syndrome in North America, the nerves' protective covering (myelin sheath) is damaged, and this interferes with the signaling process, causing weakness, numbness or paralysis.

May. 28, 2011