Guillain-Barre Syndrome

The classic scenario in GBS involves a patient who has just recovered from a typical, seemingly uncomplicated viral infection. The most common preceding infection is a Herpes infection (caused by cytomegalovirus or Epstein-Barr virus), although a gastrointestinal infection with the bacteria Campylobacter jejuni is also common. About 5% of GBS patients have a surgical procedure as a preceding event, and patients with lymphoma or systemic lupus erythematosus have a higher than normal risk of GBS. In 1976-1977, a hugely increased number of GBS cases occurred, with the victims all patients who had been recently vaccinated against the Swine flu. The reason for this phenomenon has never been identified, and no other flu vaccine has caused such an increase in GBS cases.

The cause of the weakness and paralysis of GBS is demyelination of the nerve pathways. Myelin is an insulating substance that is wrapped around nerves in the body, serving to speed conduction of nervous impulses. Without myelin, nerve conduction slows or ceases. GBS is considered an acute inflammatory demyelinating polyneuropathy (acute: having a short, severe course; inflammatory: causing symptoms of inflammation; demyelinating: destructive of the myelin sheath; polyneuropathy: disturbance of multiple nerves).

The basis for the demyelination is thought to be autoimmune (meaning that components of the patient's own immune system go out of control, and direct themselves not against an invading virus or bacteria, but against parts of the body itself). Next to nothing is understood about why certain viruses, surgical events, or predisposing conditions cause a particular patient's system to swing into autoimmune overdrive.