Guillain-Barré syndrome is a rare autoimmune disorder in which a person’s immune system mistakenly attacks parts of the peripheral nervous system, destroying the myelin sheaths that surround the nerve axons and the axons themselves, which prevents the nerves from efficiently transmitting nerve signals, thereby causing muscle weakness. Guillain-Barré syndrome may start with feelings of weakness and tingling in the feet that eventually spreads upward to the legs and arms. Over time, the intensity of these sensations may increase, leading to an inability to move certain muscles. In severe cases, Guillain-Barré syndrome can cause total paralysis, affecting breathing, blood pressure, and heart rate. Even in severe cases, most people recover from Guillain-Barré syndrome, although some may continue to experience some degree of muscle weakness. Symptoms typically peak by the third week. The cause of Guillain-Barré syndrome remains unknown, although many people report Guillain-Barré syndrome symptoms shortly after displaying respiratory or gastrointestinal viral infection symptoms. There is no known cure for Guillain-Barré syndrome. However, there are certain treatments that can accelerate recovery, including plasma exchange and immunoglobulin therapy. It also is important to keep the limbs moving to maintain muscle flexibility and strength and prevent deep vein thrombosis. Physical therapy may be beneficial once some level of limb control is regained.