Guillain–Barré syndrome (GBS) is a rapid-onset muscle weakness caused by the immune system damaging the peripheral nervous system. Typically both sides are involved and the initial symptoms are changes in sensation or pain often in the back along with muscle weakness, beginning in the feet and hands, often spreading to the arms and upper body. The symptoms may develop over hours to a few weeks. During the acute phase, the disorder can be life-threatening, with about 15 percent of people developing weakness of the breathing muscles and, therefore, requiring mechanical ventilation. Some are affected by changes in the function of the autonomic nervous system, which can lead to dangerous abnormalities in heart rate and blood pressure.
Although the cause is unknown, the underlying mechanism involves an autoimmune disorder in which the body's immune system mistakenly attacks the peripheral nerves and damages their myelin insulation. Sometimes this immune dysfunction is triggered by an infection or, less commonly, by surgery, and rarely, by vaccination. The diagnosis is usually based on the signs and symptoms through the exclusion of alternative causes and supported by tests such as nerve conduction studies and examination of the cerebrospinal fluid. There are a number of subtypes based on the areas of weakness, results of nerve conduction studies, and the presence of certain antibodies. It is classified as an acute polyneuropathy.
In those with severe weakness, prompt treatment with intravenous immunoglobulins or plasmapheresis, together with supportive care, will lead to good recovery in the majority of people. Recovery may take weeks to years, with about a third having some permanent weakness. Globally, death occurs in approximately 7.5% of those affected. Guillain–Barré syndrome is rare, at one or two cases per 100,000 people every year. Both sexes and all parts of the world have similar rates of disease.
The syndrome is named after the French neurologists Georges Guillain and Jean Alexandre Barré, who, together with French physician André Strohl, described the condition in 1916.