What is Guillain-Barré Syndrome?
Guillain-Barré Syndrome (GBS) is an acute condition associated with progressive muscle weakness and paralysis. It is an autoimmune disorder in which the body's immune system attacks its own nervous system. This causes inflammation that damages or destroys the myelin sheaths covering and insulating nerve fibres (axons) and sometimes damages the fibres themselves. Thus there are both axonal and demylinating subtypes of GBS.The demyelination process slows or stops the conduction of impulses through the nerve, interfering with motor control and causing symptoms such as tingling or numbness that typically start in the hands and feet and move progressively upward, affecting both sides of the body. GBS is a medical emergency and must be closely monitored. Those affected may become so weak that they have trouble breathing and their heart rate may become abnormal.
Guillain-Barré syndrome is a relatively rare condition, but it is the most common acquired inflammatory neuropathy and the most common causes of acute paralysis. According to the National Institute of Neurological Disorders and Stroke (NINDS), about 1 person in 100,000 will have GBS. It can affect anyone at any age but it increases in incidence with age and there is a small predominance of males. Sensory symptoms in the legs usually mark the onset of the disease followed by rapidly progressive distal weakness that soon spreads proximally. It is an unusual neuropathy in that it spontaneously reverses, and most patients recover most or all of the lost nerve and muscle function.
The exact cause of GBS and why it affects one person and not another is not well understood. The autoimmune process may be spontaneous or may be triggered by some specific disease or exposure. Infections are recognised as being important in triggering GBS and GBS is considered an immunological response to these. Antibodies against peripheral nerve gangliosides (sugar molecules) are recognised as an important mechanism of nerve damage. Many cases have been linked with a viral or bacterial infection that occurs a week or two before GBS develops. Cases have also been seen in people with HIV infection, in those with chronic diseases such as lupus (SLE), Hodgkin lymphoma (and some other malignancies), and rarely in those who have recently had a vaccination (such as for rabies or swine flu). Studies have shown that Campylobacter jejuni, Epstein Bar virus, and Cytomegalovirus are the most frequent triggering infections. Something happens during these infections that leads to a change in the immune system's ability to discriminate between "self" and "non-self." Damage to the myelin sheath and nerve is thought to involve antibodies that mistakenly target these tissues.