A rare (1-2 cases/100,000) disease of the nervous system, causing weakness of arms and legs and when severe, breathing can be impaired. Death is rare, but recovery time varies and some patients will be left with permanent sequelae. There have been rare reports of GBS days or weeks after surgery or childhood vaccination. Age over 50 and male is a risk factor. Research is ongoing as to cause but there is association with viral and bacterial infection (respiratory and gastrointestinal). An autoimmune reaction results in damage to the myelin sheath.