Guillain-Barré syndrome (GBS) is a neurological condition in which the body’s immune system attacks healthy nerve cells. In GBS the immune system targets the peripheral nervous system, which is made up of the nerves connecting the brain and spinal cord to all of our body structures. These nerves serve to control movement, transmit various sensations such as touch, hot, cold, and pain, as well as help to regulate blood pressure and other critical body functions.

GBS primarily causes muscle weakness, which mostly affects the legs and arms, but can also affect other muscles such as those controlling breathing, swallowing, and eye movements. Mild cases can make it hard to perform routine activities, such as walking; it can also cause tingling or “pins and needles” sensations, as well as pain, in the hands or feet. 

In severe cases, GBS can cause paralysis similar to what is experienced with polio and make it difficult to eat and even breathe. People of any age can get GBS, though it is more common in adults than children.

While the exact cause of GBS is unknown, it often develops several weeks following respiratory tract and gastrointestinal infections. The more common infections associated with GBS are influenza (flu), camphylobacter (bacteria in contaminated or undercooked food), cytomegalovirus, Epstein-Barr virus, hepatitis (A, B, C, and E), HIV, and COVID-19.

Rarely, GBS may occur after receiving some childhood and influenza vaccines.

The majority of people with GBS are eventually able to resume an independent and active life without any serious disability, and effective treatments are available.

“People with Guillain-Barré syndrome usually require hospitalization,” says Norman Werdiger, MD, assistant chief of neurology at Yale New Haven Hospital. “Symptoms can rapidly worsen in severity over hours or days, and early treatment can considerably shorten the course of the illness.”

When an infection occurs, the immune system produces antibodies to help destroy the infecting organism. It is thought that in GBS, some of the antibodies targeting bacterial or viral invaders mistakenly target nerve cells. This compromises nerve function, causing the symptoms of GBS.

It is unclear why in those people who develop GBS the the immune system is triggered to attack nerve cells. The vast majority of people who get viral or bacterial infections that have been linked to GBS do not develop the disorder. In very rare cases, some vaccines have also been linked to GBS.

In July 2021, the Food and Drug Administration (FDA) announced that a small number of people who received the Johnson & Johnson COVID-19 vaccine were later suspected of developing GBS. Out of a total of 12.8 million doses of this vaccine administered in the U.S., there have been around 100 reports of suspected GBS. This is about 1 to 2 cases per 100,000 vaccinated individuals. 

However, the annual incidence of GBS in the general U.S. population is about the same. Therefore, at this time it is unclear if suspected GBS cases following the Johnson & Johnson COVID vaccines are caused by the vaccine or simply a coincidence.

According to the FDA, the vaccine’s “known and potential benefits clearly outweigh the known and potential risks.” Nevertheless, the FDA has required a warning label for the Johnson & Johnson vaccine to make people aware of the possible increased risk of GBS. (The Pfizer and Moderna mRNA COVID-19 vaccines have not been linked to GBS at this time.)

The hallmark of GBS is muscle weakness that occurs on both sides of the body. The weakness is usually first noted in the legs, and then may spread up the body to the arms and head. However, weakness can begin in the arms, face or eyes, and then descends to the legs.

The weakness can make it hard to perform everyday activities such as washing, dressing, preparing meals, eating, speaking, and walking. In more severe cases, paralysis of the legs, arms, throat and breathing muscles may occur. Nerves involved in regulating the function of internal organs, and in control of blood pressure and heart rhythm, can also be affected

GBS symptoms may include:

• Difficulty breathing
• Difficulty swallowing or talking
• Difficulty controlling eye movement
• Tingling in feet and/or hands
• Pain in affected muscles (often back and legs)
• Weak or absent reflexes in affected limbs
• Abnormal heartbeat and/or blood pressure
• Balance and coordination problems
• Constipation and/or inability to empty bladder (urinary retention)

Initial symptoms of GBS may progress over the course of one to four weeks before leveling off. They may remain unchanged for months before improving.

Your doctor will ask you questions about your symptoms, including when they began, which part of your body was first affected, and whether they have spread to other parts of the body. Your doctor will also ask if you’ve recently been sick, particularly with a respiratory tract infection or GI issues. He or she will also ask if you have recently received a vaccination and what medications you have been taking.

A physical and a neurological examination are important in order to diagnosis GBS. Your doctor will examine your body to check for findings associated with GBS. During the exam, he or she will measure your blood pressure, and check your muscle strength, the reflexes in your arms and legs, and sensation and swallowing. They will also look for signs of impaired breathing and an abnormal heart rhythm.

Other tests that may be advised to confirm the diagnosis of GBS—and to exclude other possible neurological disorders as the cause for your symptoms include:

• Lumbar puncture (spinal tap). In this procedure, after giving a local anesthetic, a doctor will insert a needle into the lower back and remove a small amount of cerebrospinal fluid (the fluid that surrounds the brain and spinal cord). The fluid sample will be analyzed at a lab for protein and cell counts.  
• Nerve conduction velocity test. In this test, electrodes are placed on the skin above the nerve being tested. An electric impulse is delivered by an electrode at one site on the nerve, and recorded at another site (called an “action potential”). The test measures the speed at which the impulse moves along the nerve and the amplitude of the action potential.
• Electromyography. A doctor will insert a needle into a muscle. The needle measures the electrical activity of the muscle when it is in a relaxed and contracted state.
• Magnetic resonance imaging (MRI) study. A spinal MRI to assess the structures of the spine, including the bones, spinal cord, and nerve roots.
  
• Bloodwork. Your doctor may order blood tests to eliminate other possible causes of weakness and other symptoms.

GBS is usually treated in a hospital—often in the intensive care unit—where the patient can be closely monitored 24/7, and intensive nursing, respiratory support, and other necessary services are readily available.

Treatment of GBS involves:

Supportive care. Because GBS causes weakness in muscles involved in critical functions, many patients require frequent monitoring of breathing and cardiovascular function, as well as 24/7 nursing care for medication administration, assistance in daily hygiene, and the prevention of medical complications as a result of immobility. Some patients may require mechanical ventilation, a feeding tube, intravenous administration of medication and fluids, and assistance with bladder and bowel evacuation.

Treatment for GBS. There are two commonly used immunotherapies (treatments that affect the immune system) for GBS:

• Intravenous immunoglobulin (IVIG). This treatment involves the intravenous infusion of immunoglobulins (human-derived antibodies) into a vein.
• Plasma Exchange (plasmapheresis). In this procedure, some of the patient’s own blood is removed from a vein and passed through a machine that separates blood cells from the plasma (the liquid part of the blood). The plasma, which contains the antibodies that attack nerve cells, is discarded, and the blood cells are returned, supplemented with replacement plasma or saline, and a protein called albumin.

Many people recover faster if either of these treatments is given within the first two weeks of GBS symptom onset. Both treatments are generally well tolerated and are equally effective.

Rehabilitation. Recovery from GBS may take months, or sometimes a year or longer. People often require physical therapy to promote muscle strengthening and endurance, and to regain mobility.

The symptoms of GBS usually become most severe within four weeks of symptom onset, and then plateau. The majority of people recover, though the process may take weeks, months, or even years. Fortunately, most people who develop GBS are eventually able to return to their usual everyday and work-related activities without any significant residual physical impairment.

In some cases, even after recovery people may continue to experience weakness, pain, or fatigue, and require ongoing care. GBS is usually a once in a life-time occurrence, but a small number of people may experience a relapse.

“Yale Medicine has an experienced multidisciplinary team of readily available experts, and a dedicated neurological intensive care unit for the diagnosis, up-to-date treatment, and comprehensive care of patients with Guillain-Barré syndrome,” says Dr. Werdiger.