Guillain-Barre Syndrome (GBS)
Guillain-Barre syndrome (GBS) is an acute immune-mediated polyneuropathy and is the most common global cause of acute flaccid paralysis.
This updated UKMLA guide to GBS is based on EAN/PNS guidelines: causes, risk factors, symptoms, diagnosis, and management.
Cause and Pathophysiology
GBS is an immune-mediated polyneuropathy in which a preceding infection triggers an abnormal immune response against the peripheral nervous system.
The most accepted mechanism is molecular mimicry – infectious pathogens may induce the immune system to produce cross-reactive antibodies that mistakenly bind to human gangliosides on peripheral nerves (e.g. GM1 or GD1a)
The mechanism of nerve injury varies between subtypes:
- Acute inflammatory demyelinating polyneuropathy (AIDP) – most common subtype
- Characterised by segmental demyelination +/- secondary axonal degeneration
- Axonal subtypes – the axon itself is targeted rather than the myelin sheath
- Acute motor axonal neuropathy (AMAN)
- Acute motor and sensory axonal neuropathy (AMSAN)
Note on terminology
AIDP is the most common and classic form of GBS, but GBS is an umbrella term that also includes axonal and regional variants.
In non-specialist settings, the term GBS is often used to refer to the classic AIDP form, as this represents the most common presentation.
Risk Factors
- Peak incidence: 50-70 y/o
- Males
- Recent surgery (esp. those involving bones or digestive organs)
- Use of specific biological drugs (e.g. immune checkpoint inhibitors, anti-TNF)
- Certain vaccinations (influenza, shingles, SARS-CoV-2 adenovirus-vector vaccines) (a very small increased risk)
Clinical Features
Most common trigger: a preceding infectious illness, typically occurring within 6 weeks before symptom onset
- Implicated pathogens
- Campylobacter jejuni – highly notable bacterial trigger
- Mycoplasma pneumoniae (esp. in children)
- CMV, EBV, hepatitis E, Zika virus
- General illness symptoms
- Diarrhoea
- Respiratory infections
- Fever / influenza-like
Typical GBS (AIDP form) presentation:
| Onset and progression | Progressively worsens, but stops worsening within 4 weeks |
| Sensory symptoms | An early symptom and may precede motor symptoms
|
| Motor symptoms | Motor symptoms are more prominent than sensory symptoms
|
| Autonomic symptoms |
|
The following factors make GBS less likely:
- Asymmetrical weakness
- Predominant sensory symptoms with mild motor symptoms
- Upper motor neuron signs
Chronic inflammatory demyelinating polyneuropathy (CIDP)
- Progressive over >8 weeks
- Relapsing-remitting
- Symmetrical proximal and distal weakness
- Ascending sensory symptoms
GBS Variants
| GBS variant / subtype | Key clinical features |
|---|---|
| Miller Fisher syndrome (MFS) | Accounts for 5-25% of GBS cases:
GBS/MFS would present with the typical MFS triad and the symmetrical, progressive ascending limb weakness |
| Motor GBS | Progressive limb weakness but with NO sensory features |
| Sensory GBS | Sensory features with NO motor weakness |
| Pharyngeal-cervical brachial variant | Weakness predominantly affecting the throat, neck and arms |
| Bifacial weakness with limb paraesthesia |
|
Investigation and Diagnosis
1st line investigations for ALL suspected cases of GBS:
| Investigation | Findings in GBS |
|---|---|
| Lumbar puncture and CSF analysis | Typical finding: albuminocytologic dissociation
Note that normal CSF protein is very common in the 1st week of the disease and does NOT rule out GBS. |
| Nerve conduction test | Findings depend on the type of GBS:
|
| Electromyography |
|
Consider measuring serum anti-GQ1b antibodies if:
- Miller Fisher syndrome is suspected (88%-100% sensitivity and 100% specificity)
- Diagnostic uncertainty / atypical variants
- Poor treatment response
MRI spine should only be performed to rule out serious spine conditions (e.g. cord compression, spinal cord tumours, transverse myelitis)
Management
| Category / aspect | Description |
|---|---|
| Monitoring | Due to the risk of respiratory failure, monitor:
Elective transfer to ICU for intubation should be considered if FVC is dropping rapidly (>30% in 24 hours) or there is a low single breath count (<20) Due to the risk of autonomic instability, monitor:
|
| Disease-modifying therapy | 1st line (EITHER of the following – both are equally effective and there is no preference between the 2):
Disease-modifying therapy is indicated in most patients, apart from those with very mild disease (defined as still capable of running), as the risk and cost likely outweigh the benefits and these patients are unlikely to worsen severely. Do NOT combine IV immunoglobulin with plasma exchange or give them sequentially. Do NOT switch treatments if one fails. If a patient does not improve or continues to deteriorate after receiving a course of IVIg, do not subsequently treat them with PE and vice versa. |
| Rehabilitation | Physiotherapy, occupational therapy, and speech therapy should be started early in the acute phase (during hospital admission) and continued for more than 6 months if functional limitations persist |
The following treatments are NOT recommended:
- Corticosteroids
- Cyclophosphamide
- Mycophenolate mofetil
- Interferon beta 1a
- Eculizumab