This is a condition of nerves leading to generalize weakness developing in days to weeks usually after a bacterial or viral infection.  

What are symptoms of GBS?

Its symptoms include bilateral leg weakness, paresthesias, unsteadiness, arm weakness, facial weakness, back pain, incontinence, difficulty swallowing, and difficulty breathing. It can also cause lightheadedness, fainting, and arrhythmias of heart. These symptoms usually develop a few weeks after an infection.

 

What are the main examination findings in a patient with GBS?

Main findings are bilateral weakness, starting in legs and may also involve arms and face, loss of reflexes, and unsteadiness with no fever, or any sign suggesting a brain or spinal cord problem.

 

What is the cause of GBS?

GBS is considered an autoimmune disease. Immune responses, including antibodies, developed against a virus or bacteria cross-react and attack patient’s own body, in this case resulting in inflammation and damage of the coating or the myelin of nerves. If left untreated, this process can also damage the inside part of nerves, the axon.

 

What type of infections can cause GBS?

1. Gastroenteritis, e.g., from Compylobacter jejuni, which is the most common infection linked to GBS. Even then, it is quite rare, about 1-2 out of 10,000 cases of this infection.
2. Common respiratory tract infections, e.g., Cytomegalovirus (CMV), Epstein Barr virus (EBV), Mycoplasma pneumonia, or Hamophilus influenza virus
3. Rare infections: Zika virus, COVID-19
4. Other causes: trauma, vaccination, pregnancy, and immune suppression

 

How common is GBS?

It is a rare disorder, somewhat more common in men, and more so in elderly.  Incidence is about 1 case per 100,000 person-years.

 

How is GBS diagnosed?

It is diagnosed based upon its presentation of above described symptoms and examination. Some tests help to corroborate the diagnosis, such as analysis of spinal fluid by doing a lumbar puncture, and nerve conduction studies with electromyogram (EMG/NCS). Detail of abnormal findings on these tests is a more technical subject and briefly described in the next paragraph, in case a neurologist is reading this information.

Nerve conduction studies can be normal in early stages of GBS. Probably the earliest finding is delayed or absent late responses, the F and H responses, which can be tricky to interpret in a patient with underlying pathology. Other findings include significantly delayed distal latencies and conduction velocities, abnormal dispersion of motor unit potentials, and loss of amplitudes as patient loses axons. In early stages, there may be relative sparing of sural nerves. In rare cases, findings can be more of an axonal neuropathy than axonal. Typical CSF findings are high level of protein with or without mild elevation of white cells. 

 

How is GBS treated?

GBS requires treatment to control nerve injury triggered by antibodies. The first line of treatment is IV-Ig, intravenous immunoglobulin. This is the white part of blood after red cells are removed. It is given as an infusion over a period of 3-5 days. Alternate treatment is to clean the patient’s blood from harmful antibodies with a procedure called plasmapheresis. This procedure is similar to dialysis and done with a similar machine, few hours a day for a few days. Both treatments can help, but IV-Ig is preferred due to its relative ease of administration. Response to treatment, reversal of muscle weakness, usually takes a few more days. There can be multiple complications, e.g., involvement of muscles involved in breathing, cardiac arrhythmias, or blood clots due to lack of mobility. Patients are closely watched and usually are admitted in an intensive care unit, many times requiring a breathing machine, and high-level nursing care.

 

What if GBS is not treated?

Untreated GBS can result in permanent nerve injury and permanent weakness and disability. In many patients, GBS can affect nerves controlling breathing muscles, or the ones controlling heart rate and rhythm, both of which can result in life threatening illness. Many patients require artificial breathing, or help of a ventilator until muscle function starts to improve. Treatment is started as soon as diagnosis is made. In some cases, patients’ own immune system make adjustment and symptoms of mild GBS may improve after a few weeks. It is not possible to tell which patient may take that course, and so all patients are admitted and treated to avoid complications.

 

Are there different types of GBS?

Most GBS cases are caused by damage to the covering of nerves, the myelin. In some cases, it mainly affects the central part of nerves, the axons. So most GBS is demyelinating type (AIDP: acute inflammatory demyelinating polyradiculoneuropathy), and about 10% of cases are axonal type (AMAN: acute motor axonal peripheral neuropathy). Another variant of GBS is called Miller-Fisher syndrome. In this condition, weakness first appears in muscles controlling eye movements, resulting in double vision. It may also cause weakness of face muscles, and unsteady gait. 

 

Can GBS happen more than once?

In most cases, it does not. In about 5% of patients it can.

 

Can vaccination cause GBS?

Answer to this question depends upon the type of vaccine. Every vaccine is different and carries different risk profile. Probably the most commonly used vaccine is the annual flu shot. Studies have shown that it may slightly increase chances of having GBS, 1-2 additional cases per million people vaccinated. But, overall flu vaccine helps to decrease incidence of GBS in the community. This is because of the higher chances of getting GBS from flu than from vaccination.

 

Should patients with history of GBS not get vaccination?

Again, the answer depends upon the nature of vaccine. In general, risk of GBS associated with vaccination is very small and it does not seem to increase with prior history GBS. As a common sense, if a patient develops GBS after a few weeks of a vaccination, it is recommended not to get that type of vaccine again. Otherwise, it is more beneficial to have vaccination than not, even with prior history of GBS.

 

Where can I get more information about GBS?

American Academy of Neurology

GBS/CIDP Foundation International