Guillain Barre Syndrome has been in the news lately after the US Food and Drug Administration updated the label to one of the Covid-19 vaccines to include the possible risk of acquiring the syndrome. The vaccine in question is the Janssen(Johnson and Johnson) Covid-19 vaccine, one of the four Covid-19 vaccines approved by the government of Canada. In July the World Health Organization (WHO) met and released a statement reporting cases of Guillain Barre Syndrome following Janssen and AstraZeneca vaccine administrations. As of August 2021 there have been 50 cases of Guillain Barre Syndrome following Covid-19 vaccination in Canada. Of the nearly 600 million people vaccinated worldwide there have been approximately 800 cases reported of the disease. It once again brings up the question of vaccines and the rare association with Guillain Barre Syndrome and vaccine hesitancy as a result.
What is Guillain Barre Syndrome?
Guillain Barre Syndrome (GBS) is an autoimmune mediated disease that leads to progressive neuromuscular paralysis. It is the most common form of acute neuromuscular paralysis in the world and if left untreated can cause long-term complications and possibly even death. GBS used to be considered as a single disorder but is now considered a syndrome of many different variants.
What are the signs and symptoms of GBS?
GBS is characterized by a rapid progressive symmetric paralysis and weakness of the legs and arms. It almost always occurs in an ascending pattern, which is paralysis that generally starts in the lower extremities and migrates to eventually involve the torso. In addition to weakness and paralysis patients inflicted with GBS will experience numbness and loss of sensation in their extremities. Patients will often describe numbness and will have either absent or weak deep tendon reflexes. Symptoms often occur rapidly as patients will often describe preceding infection couple weeks prior to symptom onset. It is a potentially life threatening disorder because of the risk of respiratory compromise and autonomic dysfunction that could lead to blood pressure drops, arrhythmias and cardiac arrest. Respiratory failure due to diaphragmatic weakness is the most life threatening complication.
What are the most common causes of GBS?
As mentioned earlier the most common cause of GBS is a preceding infection usually of the gastrointestinal or respiratory tract. The most commonly implicated organism is Campylobacter jejuni, which accounts for roughly 40 percent of GBS patients. Other infectious microorganisms that have been documented to cause GBS include Cytomegalovirus, Epstein Barr virus, Zika virus, HIV etc. Other less commonly triggering events of GBS include surgery, trauma, and even vaccinations.
How does an infection cause GBS?
The mechanism of the development of GBS is not one hundred percent understood. The most commonly accepted theory is that during the stages a patient is recovering from an infection, antibodies that were formed by the white blood cells in our immune system to fight off the initial offending pathogen will cross-react with antigenic components found on our peripheral nerves. In particular the B-cells produce antibodies that target the proteins found on the surfaces of the myelin sheath or the axons of nerve cells. This proposed mechanism of infection is what is known as molecular mimicry.
Can vaccines cause an increased risk of acquiring GBS?
One of the triggering events of GBS that has caused a scare in the general public are vaccinations. There have been studies that have shown that the influenza vaccine is associated with an increased risk of GBS though this risk is considered negligible with 1 to 2 cases of GBS occurring per million people vaccinated with the influenza vaccine. Despite this the risk of developing GBS from the vaccine is much less than the health risk of acquiring influenza in the unvaccinated. Other vaccinations that have been associated with a risk of GBS include meningococcal and most recently Covid-19 vaccine. Like influenza vaccines, the risks are negligible and the benefits of the vaccines outweigh the risk of acquiring GBS.
How is GBS diagnosed?
The history and physical history of a patient with a suspicion of GBS is very important as the initial diagnosis of GBS is based on clinical presentation. As stated earlier patients will often describe paralysis that is equal on both sides and rapidly progressing in addition to a history that includes a preceding infection. The diagnosis can be confirmed in electrodiagnostic studies that show findings consistent with GBS. These studies include electromyography and nerve conduction tests. In addition to electrodiagnostic studies, lumbar puncture can be performed to confirm the diagnosis. Cerebrospinal fluid will show normal white blood cell count and elevated cerebrospinal fluid protein which is known as albuminocytologic dissociation.
How common is GBS in the population?
GBS does occur world wide with an incidence rate of 1 to 2 cases for every 100,000 per year. It is a disease that affects all age groups although the rate of GBS cases is higher in older patients with case rates increasing 20 percent with every 10-year increase in age. Males are affected more than females.
How is GBS treated and what are the chances of a full recovery?
Patients who are diagnosed with GBS require hospital admission because of the need for supportive care and to monitor respiratory and autonomic functions. Up to 30 percent of patients will end up requiring ventilator support.
The mainstay of therapy for GBS is plasmapheresis and intravenous immunoglobulin as they speed up the recovery process. Plasmapheresis involves the removal of the harmful antibodies against the peripheral nerve cells. Treatment administered earlier than 4 weeks of symptom onset has been shown to lead to favourable outcomes and decreased risk of complications associated with GBS.
The prognosis of GBS is generally favourable in the majority of the patients with proper and prompt treatment, with nearly 85 patients recovering completely months after symptom onset. There are however certain factors that put certain populations at greater risk of developing long term outcomes than the general population. These risk factors include but are not limited to; patients older than 60 years of age, patients who during their hospital admission required ventilator support, and patients who on admission presented with severe muscle weakness and paralysis in addition to very abnormal electrodiagnostic findings.