Guillain-Barre syndrome (GBS) is a rare neurological disorder in which the body's immune system mistakenly attacks part of its peripheral nervous system-the network of nerves located outside of the brain and spinal cord. GBS can range from a very mild case with brief weakness to nearly devastating paralysis, leaving the person unable to breathe independently. Fortunately, most people eventually recover from even the most severe cases of GBS. After recovery, some people will continue to have some degree of weakness.
Guillain-Barre syndrome can affect anyone. It can strike at any age (although it is more frequent in adults and older people) and both sexs are equally prone to the disorder. GBS is estimated to affect about one person in 100,000 each year.
Many of the body’s nerves are like household wires. There is a central conducting core in the nerves called the axon that carries an electric signal. The axon (an extension of a nerve cell) is surrounded by a covering, like insulation, called myelin. The myelin sheath surrounding the axon speeds up the transmission of nerve signals and allows the transmission of signals over long distances.
When we move, for example, an electric signal from the brain travels through and out of the spinal cord to peripheral nerves along muscles of the legs, arms, and elsewhere—called motor nerves. In most cases of GBS, the immune system damages the myelin sheath that surrounds the axons of many peripheral nerves; however, it also may also damage the axons themselves. As a result, the nerves cannot transmit signals efficiently and the muscles begin to lose their ability to respond to the brain's commands. This causes weakness.
The weakness seen in GBS usually comes on quickly and worsens over hours or days. Symptoms are usually equal on both sides of the body (called symmetric). In addition to weak limbs, muscles controlling breathing can weaken to the point that the person must be attached to a machine to help support breathing.
Since nerves are damaged in GBS, the brain may receive abnormal sensory signals from the rest of the body. This results in unexplained, spontaneous sensations, called paresthesias, that may be experienced as tingling, a sense of insects crawling under the skin (called formications), and pain. Deep muscular pain may be experienced in the back and/or legs.