Acute idiopathic polyneuritis, also referred to as Guillain-Barre syndrome, is a condition marked by gradually worsening symmetrical weakness and a decrease or loss of reflexes, typically starting in the legs. In most cases, individuals experience near or complete recovery. This syndrome is not linked to fever and is characterized by paralysis affecting multiple limbs, most often the legs, with the paralysis worsening over time. There is a loss or reduction of reflexes in the legs and arms. It is important to differentiate this syndrome from other conditions with similar symptoms.Guillain-Barre syndrome is caused by an immune response that directly damages the myelin sheath surrounding peripheral nerves or the nerve axons themselves. This syndrome can sometimes be triggered by certain events, such as vaccinations. Vaccines that have been associated with Guillain-Barre syndrome include the swine flu vaccine from 1976-1977, the oral poliovirus vaccine, and the tetanus toxoid. In addition to vaccines, infections with the bacterium Campylobacter jejuni and various viral infections can also precipitate the syndrome.