Guillain-Barré syndrome is thought to be caused by an autoimmune reaction.
Usually, weakness begins in both legs and moves up the body.
Electromyography and nerve conduction studies can help confirm the diagnosis.
People with Guillain-Barré syndrome are hospitalized immediately because symptoms can worsen rapidly.
Immune globulin given intravenously or plasma exchange speeds recovery.
(See also Overview of the Peripheral Nervous System Overview of the Peripheral Nervous System The peripheral nervous system refers to the parts of the nervous system that are outside the central nervous system, that is, those outside the brain and spinal cord. Thus, the peripheral nervous... read more .)
Guillain-Barré syndrome affects many peripheral nerves Overview of the Peripheral Nervous System The peripheral nervous system refers to the parts of the nervous system that are outside the central nervous system, that is, those outside the brain and spinal cord. Thus, the peripheral nervous... read more throughout the body (a polyneuropathy Polyneuropathy Polyneuropathy is the simultaneous malfunction of many peripheral nerves throughout the body. Infections, toxins, drugs, cancers, nutritional deficiencies, diabetes, autoimmune disorders, and... read more ).
The presumed cause of Guillain-Barré syndrome is an autoimmune reaction Autoimmune Disorders An autoimmune disorder is a malfunction of the body's immune system that causes the body to attack its own tissues. What triggers an autoimmune disorder is not known. Symptoms vary depending... read more . The body’s immune system attacks one or both of the following:
The myelin sheath, which surrounds the nerve and enables nerve impulses to travel quickly
The part of the nerve that sends messages (called an axon Typical Structure of a Nerve Cell
)
In about two thirds of people with Guillain-Barré syndrome, symptoms begin about 5 days to 3 weeks after a mild infection (such as a Campylobacter infection Campylobacter Infections Several species of the gram-negative bacteria Campylobacter (most commonly Campylobacter jejuni) can infect the digestive tract, often causing diarrhea. People can be infected... read more , mononucleosis Infectious Mononucleosis Epstein-Barr virus causes a number of diseases, including infectious mononucleosis. The virus is spread through kissing. Symptoms vary, but the most common are extreme fatigue, fever, sore throat... read more 
, or another viral infection), surgery, or a vaccination.
In a few people, Guillain-Barré syndrome has developed after a Zika virus infection, Zika Virus Infection Zika virus infection is a mosquito-borne viral infection that typically causes no symptoms but can cause fever, rash, joint pain, or infection of the membrane that covers the white of the eye... read more 
or after COVID-19 COVID-19 COVID-19 is an acute respiratory illness that can be severe and is caused by the coronavirus named SARS-CoV-2. Symptoms of COVID-19 vary significantly. Two types of tests can be used to diagnose... read more .
Insulating a Nerve Fiber
Most nerve fibers inside and outside the brain are wrapped with many layers of tissue composed of a fat (lipoprotein) called myelin. These layers form the myelin sheath. Much like the insulation around an electrical wire, the myelin sheath enables nerve signals (electrical impulses) to be conducted along the nerve fiber with speed and accuracy. When the myelin sheath is damaged (called demyelination), nerves do not conduct electrical impulses normally.  |
Weakness caused by Guillain-Barré syndrome usually worsens over 3 or 4 weeks, then remains the same or starts to return to normal. If it worsens for more than 8 weeks, it is considered chronic inflammatory demyelinating polyneuropathy Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) Chronic inflammatory demyelinating polyneuropathy is a form of polyneuropathy that, like Guillain-Barré syndrome, causes increasing muscle weakness, but the weakness progresses for more than... read more (CIDP), not Guillain-Barré syndrome.
Symptoms of GBS
Symptoms of Guillain-Barré syndrome usually begin in both legs, then progress upward to the arms. Occasionally, symptoms begin in the arms or head and progress downward.
Symptoms include weakness and a pins-and-needles sensation or loss of sensation. Weakness is more prominent than abnormal sensation. Reflexes are decreased or absent. In 90% of people who have Guillain-Barré syndrome, weakness is most severe 3 to 4 weeks after symptoms start. In 5 to 10%, the muscles that control breathing become so weak that a mechanical ventilator is needed.
When the disorder is severe, the facial and swallowing muscles become weak in more than half of affected people. When these muscles are weak, people may choke when they are eating or become dehydrated and malnourished.
If the disorder is very severe, internal functions controlled by the autonomic nervous system Overview of the Autonomic Nervous System The autonomic nervous system regulates certain body processes, such as blood pressure and the rate of breathing. This system works automatically (autonomously), without a person’s conscious... read more 
may be impaired. For example, blood pressure may fluctuate widely, heart rhythm may become abnormal, people may retain urine, and severe constipation may develop.
In a variant called Miller-Fisher syndrome, only a few symptoms develop: Eye movements become paralyzed, walking becomes unsteady, and normal reflexes disappear.
Diagnosis of GBS
A doctor's evaluation
Electromyography and nerve conduction studies, magnetic resonance imaging, blood tests, and a spinal tap
Doctors can usually diagnose Guillain-Barré syndrome based on the pattern of symptoms. However, tests are done to confirm the diagnosis. If doctors suspect Guillain-Barré syndrome, people are admitted to the hospital to have the tests because the syndrome can worsen rapidly and impair the muscles involved in breathing. Breathing is evaluated frequently.
Tests may include the following:
Analysis of cerebrospinal fluid (which surrounds the brain and spinal cord) obtained by a spinal tap Spinal Tap Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Electroencephalography (EEG) is a simple, painless procedure in which... read more
(lumbar puncture)Magnetic resonance imaging (MRI)
Blood tests
These tests can help doctors exclude other possible causes of severe weakness, which may resemble Guillain-Barré syndrome. For example, MRI can help exclude spinal cord damage due to compression Compression of the Spinal Cord Injuries and disorders can put pressure on the spinal cord, causing back or neck pain, tingling, muscle weakness, and other symptoms. The spinal cord may be compressed by bone, blood (hematomas)... read more (for example, by a tumor or an abscess) and transverse myelitis Acute Transverse Myelitis Acute transverse myelitis is inflammation that affects the spinal cord across its entire width (transversely) and thus blocks transmission of nerve impulses traveling up or down the spinal cord... read more (inflammation of the spinal cord).
A combination of high protein levels and few or no white blood cells in the cerebrospinal fluid and characteristic results from electromyography strongly suggest Guillain-Barré syndrome.
Prognosis of GBS
Damage stops progressing within 8 weeks. Without treatment, most people with Guillain-Barré syndrome improve slowly over several months. However, with early treatment, people can improve very quickly—in days or weeks.
About 30% of adults and even more children with the disorder have residual weakness 3 years after the syndrome began. On average, fewer than 2% of people die.
After initial improvement, 3 to 10% of people with Guillain-Barré syndrome develop chronic inflammatory demyelinating polyneuropathy Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) Chronic inflammatory demyelinating polyneuropathy is a form of polyneuropathy that, like Guillain-Barré syndrome, causes increasing muscle weakness, but the weakness progresses for more than... read more .
Treatment of GBS
Hospitalization and supportive care
If needed, use of a ventilator to help with breathing
Immune globulin or plasma exchange
Guillain-Barré syndrome can worsen rapidly and is a medical emergency. People who develop this syndrome should be hospitalized immediately. The sooner appropriate treatment is started, the better the chance of a good outcome. If symptoms strongly suggest Guillain-Barré syndrome, treatment is usually started without waiting for test results.
Supportive care
In the hospital, people are closely monitored so that breathing can be assisted with a ventilator if necessary.
People with weak facial and neck muscles may need to be fed through a catheter inserted in a vein (intravenous feeding Intravenous Feeding Intravenous feeding is used when the digestive tract cannot adequately absorb nutrients, as occurs in severe malabsorption disorders. It is also used when the digestive tract must be temporarily... read more ) or through a tube placed directly into the stomach (a gastrostomy tube) or small intestine (a percutaneous endoscopic gastrostomy or PEG tube Tube Feeding Tube feeding may be used to feed people whose digestive tract is functioning normally but who cannot eat enough to meet their nutritional needs. Such people include those with the following... read more 
) through a small incision in the abdomen. Fluids may be given intravenously.
Being unable to move because muscles are weak can cause many problems, such as pressure sores Pressure Sores Pressure sores are areas of skin damage resulting from a lack of blood flow due to prolonged pressure. Pressure sores often result from pressure combined with pulling on the skin, friction,... read more 
and stiff, permanently shortened muscles (contractures). So nurses take precautions to prevent pressure sores and injuries by providing soft mattresses and by turning the people with severe weakness every 2 hours.
Physical therapy is started to help prevent contractures and preserve joint and muscle function and the ability to walk. Heat therapy may be used to make physical therapy more comfortable. Physical therapy may begin with the therapist moving the limbs for people (passive exercise). As the weakness subsides, people should move their own limbs (active exercise).
Immune globulin or plasma exchange
Immune globulin (a solution containing many different antibodies collected from a group of donors), given early and by vein (intravenously) for 5 days, is the treatment of choice for Guillain-Barré syndrome.
If immune globulin is ineffective, plasma exchange Plateletpheresis (platelet donation) In addition to normal blood donation and transfusion, special procedures are sometimes used. In plateletpheresis, a donor gives only platelets rather than whole blood. Whole blood is drawn from... read more (filtering of toxic substances, including antibodies to the myelin sheath, from the blood) can help.
These treatments shorten the hospital stay, speed recovery, and reduce the risk of death and permanent disability. Plasma exchange is usually done as soon as possible if people are worsening quickly. However, removing and replacing a lot of blood through a tube (catheter) inserted in a vein can cause low blood pressure and increase the risk of infection.
Because plasma exchange removes immune globulin from the blood, plasma exchange is not used at the same time as immune globulin. Plasma exchange is delayed for at least 2 to 3 days after immune globulin is given.
Other treatments
Corticosteroids do not help and may worsen Guillain-Barré syndrome.
