A Review of Guillain-Barre Syndrome

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Introduction

By Cassandra Lis

Figure 1. This images depicts someone who has been intubated as a result of Guillain-Barre syndrome. This particular person had a C-section, epidural, and the flu before the onset of their symptoms. This image came from hollyaftergbs blog.

Guillain-Barré syndrome (GBS) is a rare disorder characterized by neuropathy that has a mortality rate of 4% to 7%. The effects of Guillain-Barré syndrome are the most common cause of quadriparesis, muscle weakness in all four limbs, in the world (1-2 cases per 100,000 people). Before 1979, the most common cause of quadriparesis was polio, but the introduction of the vaccine eradicated polio in the US and the rest of the world besides Pakistan, Afghanistan, and Nigeria. In this disorder, it is believed that the immune system attacks the nerves, so symptoms relating to nerve degeneration are normally the symptoms that are first noticed. Some of the symptoms of this disorder are weakness in legs, unsteady walking, feeling achy, shooting pain, high pulse, and labored breathing. The most common first symptom is weakness and tingling in the lower extremities which later spreads to the upper body.

There are four main types of Guillain-Barré syndrome: acute inflammatory demyelinating polyradiculoneuropathy, Miller Fisher syndrome, Acute motor axonal neuropathy, and acute motor-sensory axonal neuropathy. Acute inflammatory demyelinating polyradiculoneuropathy (AIDP) is the type of Guillain-Barré that is most common in Europe and North America and people in these regions use GBS and AIDP interchangeably (4). AIDP has three phases as it progresses, the first of which being rapidly worsening muscle weakness. After this stage, the muscle weakness becomes stable but other symptoms occur like cardiac disruptions or gastric dysmotility (4). The final stage is when the symptoms gradually fade away. However, many people have weakness or pain for years after the syndrome (4).

Miller Fisher syndrome (MFS) has a different characterization than AIDP. This syndrome is associated with unsteady ambulation, areflexia (loss of reflexes), and ophthalmoplegia (weakness of eye muscles)(5). MFS shares characteristics with Bickerstaff brainstem encephalitis, which impacts the central nervous system more than MFS does. People who have had MFS normally recover in a few months, but there are also numerous patients who display other forms of GBS in addition to the MFS. In these overlap cases, respiratory failure is also a common side effect. (5)

Acute motor axonal neuropathy (AMAN) is less common in western countries, but accounts for 30% to 50% of Guillain-Barré syndrome cases in both Asia and Latin America (6). This form of GBS is more severe in its onset of weakness and poor reflexes than AIDP. Many patients with this form of GBS need assistance with respiration, which is achieved through the use of a ventilator (6). AMAN onset is often associated with enteritis caused by Campylobacter jejuni. Recovery in AMAN differs from the other forms of GBS because it can occur much quicker. However, if the person has severe axonal degeneration, the recovery process is longer (6).

Acute motor-sensory axonal neuropathy (AMSAN) is similar to AMAN in both its proposed pathological mechanism and symptoms. However, this disease is very severe, so the recovery process is very poor (7). This is because the illness affects the sensory nerves and roots, which causes motor and sensory dysfunction (7).

This images depicts a scanning electron microscopy of Campylobacter jejuni, a bacteria that causes foodborne infections (food poisoning). The brown lines are the flagella. This bacteria is also associated with the onset of Guillain-Barré syndrome. This image came from University of Leicester.

Guillain-Barré syndrome has many different causes, and the majority of them are bacterial or viral in nature. Campylobacter jejuni, influenza virus, cytomegalovirus, Epstein-Barr virus, Zika virus, Hepatitis A/B/C/E, HIV, mycoplasma pneumonia, surgery, Hodgkin’s lymphoma, vaccinations (very rarely), and COVID-19 infections are all believed to trigger the syndrome. Although these can trigger Guillain-Barré syndrome, the actual underlying cause of this disorder is unknown. It does not spread between people and it is not a heritable illness. The specific mechanisms of the disease are currently being investigated and are of high interest in the medical community.

Current research is finding that several medicines are also associated with the onset of forms of GBS. For example, a 2019 case study finds that rivaroxaban, also known as xarelto, may be associated with GBS. Rivaroxaban is a commonly used anticoagulant, which prevents deep vein thrombosis, strokes, and heart attacks. The patient in the case study had a history of diabetes, and they developed quadriparesis after 5 days of treatment with rivaroxaban. Nerve conduction studies found that there was a reduction in amplitude for both the tibial and right peroneal nerves. There was also reduced sensory nerve action potential in the right ulnar nerve. These findings indicated that the patient was experiencing demyelinating neuropathy. The surprising finding about this patient was that there were no recent records of infection or vaccinations, which indicated that something new or unknown caused the onset of GBS. Rivaroxaban was stopped and the patient was treated with intravenous immunoglobulin and neurorehabilitation to combat the GBS. He was able to walk after 2 months of stopping the rivaroxaban. The reason why rivaroxaban causes GBS is unknown, but it is likely that there was an allergic reaction to the drug or a neurotoxin effect that caused demyelination.

Pathological Mechanisms

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Diagnosis

GBS is difficult to diagnose because many of the symptoms of GBS are similar to the symptoms of other disorders. This means that physicians often find that they must rule out many other diseases or illnesses before they are able to diagnose the patient with GBS. After physicians do a complete history and physical examination, they might draw complete blood counts and metabolic panels for labs as a quick way to eliminate other disorders. The specific diagnostic criteria for GBS include a progressive symmetrical weakness with decreased reflexes. The peak of the symptoms must also occur within four weeks of the onset of the symptoms. Each type of GBS has differing symptoms, so the specific diagnosis of a patient is informed by the symptoms that they are experiencing.

One of the ways that physicians diagnose GBS is through a spinal tap. In a spinal tap, fluid is drawn from the spinal canal. The fluid is then tested by other means in order to determine if the patient has GBS. In the fluid, physicians look for increases in protein with a normal white blood cell count. This is known as albuminocytologic dissociation and is found in 9 of 10 GBS patients. If the patient has elevated lymphocyte counts, this might indicate other issues like sarcoidosis or Lyme disease neuropathy.

Another way that GBS may be detected is through nerve conduction studies. This is a study where electrodes are placed on the skin above the nerves and small shocks are passed through the different electrodes. This measures the speed of the nerve signals as the shocks travel from nerve to nerve. These are especially useful because they allow physicians to differentiate between the different types of GBS. (11) Physicians are able to distinguish between the different types because AIDP is characterized by conduction slowing, conduction blocks, and abnormal temporal dispersion but patients with AMAN have reduced compound muscle action potential amplitudes.(12) Electromyography is another study that uses electrodes that can also help to diagnose someone with GBS. In this study, electrodes are inserted into the muscles in order to measure nerve activity at that specific muscle.

Treatment

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Controversies with Vaccines

Although GBS is very rare, people are still concerned about acquiring this illness as a side effect of vaccines. This is because in 1976, there was an increase in GBS cases after receiving the swine flu vaccine. However, the risk of acquiring GBS after the swine flu vaccine was about 1 case for every 100,000 people who got the 1976 swine flu vaccine. The reason why this occurred is not really known. The CDC monitors the number of people with Guillain-Barré syndrome during flu season in order to see if there is a larger association between GBS and the flu vaccine. Each year, the risk of developing Guillain-Barré syndrome from an influenza vaccine is between 1 to 2 people per one million vaccinated. However, it is much more likely that a person could develop GBS after getting the flu compared with the vaccine. On the CDC information sheet for the influenza vaccine, Guillain-Barré syndrome is mentioned as a potential side effect of the vaccine, and it is recommended that a person who previously had GBS speak with their healthcare provider before receiving the vaccine.

Risks of vaccination are very important to consider because many people use these potential side effects as justification for not receiving vaccinations. According to a 2020 study, the number of anti-vaxxers, people who oppose receiving vaccines, has increased by at least 7.8 million people since 2019. (15) This was determined using the presence of social media accounts and followers of social media that spread anti-vaccination sentiments. In addition, approximately 1 in 6 British people were unlikely to get vaccinated against COVID-19. Currently, the world needs to vaccinate as many people as possible to create herd immunity and prevent the spread of COVID-19 and protect people against harmful mutants that are beginning to develop.

Anti-vaxxers spread misinformation about the likelihood of developing GBS and other conditions after vaccination in order to scare other people into not receiving vaccines. This is very harmful to everyone because there are many people who are unable to receive either due to allergies like latex or religious reasons. One of the religious reasons that Muslim people, for example, do not receive some vaccinations is because they contain gelatin, which is a pork product. When anti-vaxxers refuse to vaccinate their children, they are disrupting the herd immunity that scientists have developed by vaccinating the majority of the population. This is done to protect people who are unable to receive vaccinations. If more parents refuse to vaccinate their children, then the people who are unable to be vaccinated will be at higher risk of developing the illness. For example, in the US there were 1282 cases of measles in 2019, which was a large increase from the previous year (see Figure 6).(16) The number of cases went down in 2020, but this was likely due to people wearing masks and social distancing because of COVID-19. In order to protect vulnerable populations, everyone who is eligible should be vaccinated. Scientists can promote vaccinations by making the information about them easily accessible to people who did not study science.

References

Authored for BIOL 238 Microbiology, taught by Joan Slonczewski, 2021, Kenyon College.