DefinitionGuillain-Barre syndrome is a serious disorder that occurs when the body's defense (immune) system mistakenly attacks part of the nervous system. This leads to nerve inflammation that causes muscle weakness.Alternative NamesLandry-Guillain-Barre syndrome; Acute idiopathic polyneuritis; Infectious polyneuritis; Acute inflammatory polyneuropathyCauses, incidence, and risk factorsGuillain-Barre syndrome is an autoimmune disorder (the body's immune system attacks itself). Exactly what triggers Guillain-Barre syndrome is unknown. The syndrome may occur at any age, but is most common in people of both sexes between ages 30 and 50.It often follows a minor infection, usually a lung infection or gastrointestinal infection. Usually, signs of the original infection have disappeared before th