What is GBS?
Guillain-Barré (pronounced ghee-yan bar-ray) Syndrome, or GBS for short, is a rare and serious inflammatory neuropathy that damages the peripheral nerves. It affects one to two people per 100,000 per year (around 1,300 people each year in the United Kingdom).
People of all ages can develop GBS, but it is more common in adults, and in men than in women. It is neither hereditary nor infectious, so you can’t pass it on to your children, or transmit it to someone else.
Guillain-Barré syndrome is thought to be caused by an over-reaction of the immune system, the body’s natural defence against illness and infection. Normally the immune system attacks any germs that get into the body. A disease in which the immune system attacks its own body id called an autoimmune disease. In people who develop Guillain-Barré syndrome, the immune system experiences a sort of allergic reaction to the infection and it mistakenly attacks the peripheral nerves.
The immune reaction in GBS causes the myelin to become inflamed and may also damage the axons. This prevents signals from the brain travelling along the nerve fibres properly, which can cause numbness, weakness and pain in the limbs. Because many nerves are inflamed, GBS is called a ‘polyneuropathy’.
GBS worsens for up to four weeks. Unfortunately, recovery usually takes much longer than this. Most people will eventually make a good recovery, but it can be life-threatening, and some people are left with long-term problems, from severe fatigue to dexterity and mobility issues. GBS is a one-off condition which usually does not happen again, except in around 3% who may suffer GBS more than once, perhaps many years later.
Symptoms of GBS
Symptoms of Guillain-Barré syndrome usually develop rapidly, starting in the feet and legs before spreading to other parts of the body. These symptoms affect both sides of the body at the same time, usually symmetrically.
At first you may have:
The symptoms may continue to get worse over the next few days or weeks, typically reaching the worst point, or nadir, within two weeks and always within four weeks.
Some people are only mildly affected, but others may have:
The worst degree of weakness is usually reached within two to four. Some people worsen very rapidly to severe paralysis within a few days, but this is uncommon. The person then stays the same (plateau or stabilization) a few days or weeks. Many people are so weak that they are unable to get out of bed. However, it is very important that someone keeps all the joints moving to stop them stiffening up. A physiotherapist may advise relatives and friends on what they can do to help.
Around 20% of people with GBS develop weakness of the breathing muscles and need mechanical ventilation. Cardiac arrythmia (irregular heartbeat), very high or low blood pressure and constipation may occur if there is inflammation of the autonomic nerve, supplying internal organs. About 2-5% of people with GBS die.
Is there more than one type of GBS?
Yes. The word ‘syndrome’ in GBS means it is not a single disease but includes several different diseases which may look similar.
The most common type of GBS is acute inflammatory demyelinating polyneuropathy or AIDP. ‘Acute’ means starting quickly, ‘Inflammatory’ means a reaction of the immune system, for example when your skin is inflamed it looks red and feels uncomfortable. ‘Demyelinating’ means damage to the myelin. ‘Polyneuropathy’ means a disease affecting the nervers. The myelin sheath is mand and repaired by cells called Schwann cells. People with AIDP typically have numbness/tingling as well as weakness. In more severe forms of AIDP, both the axon and the myelin may be damaged, giving slower recovery.
AMAN and AMSAN
The axon is the conducting core of the nerve, equivalent to the copper wire within electrical cables. In AIDP this is usually not damaged. However, in the variants called AMAN (acute motor axonal neuropathy) and AMSAN (acute motor and sensory axonal neuropathy), the axon is damaged too. Recently, variants of axonal GBS have been discovered in which the axon is temporarily blocked by antibodies without much damage, which can therefore recover more quickly. These may be called paranodopathy, acute motor conduction block neuropathy, or reversible conduction failure.
The speed of recovery depends on the type and severity of damage. Demyelination, inflammation and antibodies usually improve within week. If there is damage (degeneration) of the axons, recovery takes many months or up to three years, and is often incomplete. If the muscles have become very thin (wasted) this usually indicates axonal damage and a slower recovery. Axonal degeneration may occur in either AIDP or axonal GBS. The distinction between AIDP and axonal GBS does not affect treatment or the speed of recovery. The factors which usually indicate a slower recovery are: more severe weakness, older age, and diarrhea just before GBS starts.
In some cases, an initial diagnosis of GBS may later be changed to CIDP, a chronic variant in which nerve inflammation lasts for years. ‘Chronic’ means continuing for a long time. CIDP stands for Chronic Inflammatory Demyelinating Poly(radiculo)neuropathy. By definition, in CIDP the symptoms continue to worsen more than 8 weeks after onset, usually after improving first. If someone with severe GBS is not improving, this is more likely GBS with axonal damage than CIDP. CIDP
and other chronic variants are described in the GAIN booklet CIDP and associated chronic variants.
Although the commonest (classical) form of GBS causes weakness and sensory loss throughout the whole body, some people with GBS may have one of several variants which look different.
Pattern of symptoms in variants of Guillain–Barré syndrome
These variants include:
- weakness without sensory loss (pure motor variant, usually AMAN)
- weakness only in face and cranial nerves (facial palsy with paraesthesias):
- weak face, tingling in the arms/legs but no weakness in the arm/legs,
- weakness only in arms, neck and throat (pharyngeal–cervical–brachial variant)
- weakness only in legs (paraparetic variant)
- Miller Fisher syndrome (MFS).
GBS variants are rarely ‘pure’ but often overlap in part with classical GBS. Antibodies to molecules called gangliosides are found in many of these variants, but not usually in classical AIDP.
Miller Fisher syndrome and variants
Miller Fisher syndrome (MFS) is also known as Fisher’s syndrome. MFS typically causes
- abnormal coordination (‘ataxia’, such as clumsiness and poor balance as if drunk),
- paralysis of eye movements (‘ophthalmoplegia’, which may cause difficulty reading or double vision), and
- absent tendon reflexes (‘areflexia’, detectable by a doctor but causes no symptoms).
Often there is weakness of the face but many people have no weakness.
Variants of Miller Fisher syndrome
- Some people with MFS also have weakness of the whole body and are then considered to have an overlap of both MFS and GBS. The speed of recovery is largely determined by the severity of the GBS.
- If GBS causes weakness of eye movements (which it usually doesn’t) this is also an overlap with MFS.
- Rare milder variants of MFS may have weakness only of eye movements (‘acute ophthalmoparesis’).
- Bickerstaff’s brainstem encephalitis (BBE) means MFS with additional inflammation of the brainstem. This typically causes drowsiness or reduced consciousness, often with whole-body weakness, and may be shown on MRI scanning or by neurological examination. BBE is the only variant of GBS affecting the brain; otherwise GBS and MFS affect only the peripheral nerves not the brain.
Antibodies to ganglioside GQ1b (IgG type) are found in most patients with MFS and its variants (but not other types of GBS), suggesting they are all closely related.
About two thirds of people who develop GBS had an infection within the preceding six weeks. Usually this is a fever, chest infection, or flu-like illness without detecting a specific infecting organism.
If a specific infection is found, the most common is Campylobacter bacteria which causes severe diarrhoea, typically caught by food poisoning such as from eating under-cooked chicken. Other specific infections that are proven sometimes to trigger GBS include: influenza, Haemophilus influenzae, mycoplasma pneumoniae, hepatitis A, hepatitis E, cytomegalovirus (CMV), glandular fever (Epstein-Barr virus), and Zika. Most of these just cause mild flu-like symptoms or a chest infection.
Most people who catch these infections don’t develop GBS. GBS only happens rarely if the infection triggers a sort of allergic reaction of the immune system against a person’s nerves. After Campylobacter infection the risk of developing GBS is under 1 in 1,000.
GBS is sometimes triggered by major surgery including transplant surgery. Rarely GBS is triggered by certain biological drugs used for treating cancer or other diseases. Sometimes, no trigger or infection can be identified.