In Guillain-Barré syndrome (GBS), the body's immune system attacks the nerves outside the brain and spinal cord (the peripheral nerves). This causes temporary weakness or even paralysis (being unable to move) in parts of the body. It is rare disease, but can be serious. If it affects the chest muscles, child can have breathing trouble and need to use a ventilator for a while. The paralysis/ weakness is usually temporary.

The peripheral nerves send signals from the brain to the muscles and tell them to move. They also send sensory signals (such as touch, pressure, temperature, and pain) to the brain. Guillain-Barré syndrome temporarily damages these nerves, which interrupts the signals. So, someone with the condition may have weakness or problems moving, or may feel pain, numbness, or tingling in the arms or legs.

In GBS, the attack on the immune system usually involves proteins called antibodies. Normally these helps destroy invading bacteria or viruses. But in GBS, these antibodies mistakenly damage parts of the peripheral nerves. Many people with the condition have had a viral or bacterial infection in the 2 weeks before symptoms began. The infections usually are in the respiratory system or gastrointestinal tract.

It is diagnosed based on symptoms, examination, nerve conduction study, CSF study and sometimes MRI.

Treatments that can speed recovery include:

Immunoglobulin (IVIg) therapy: This injection of healthy antibodies helps lessen the immune system's attack on the body.

Plasmapheresis or plasma exchange: A machine pumps blood out of the body, removes the cells attacking the nervous system, and returns blood to the body.