By Roshan Raju Varghese (4th year, Newcastle University)

with the odd bit pitched in for good measure from me - Ed

Definition

• An acute inflammatory demyelinating polyneuropathy (AIDP).
• Essentially it is a peripheral neuropathy

it kind of does what it says on the tin - presents acutely, is inflammatory (immune), demyelinates (mostly) and hits many (poly) nerves (neuropathy)

Aetiology

• Autoimmune process often triggered by infection.
• The most common ones are either GI or respiratory infection. However, keep an open mind and it could sometimes be secondary to vaccinations

campylobacter is notorious for this and causes more severe cases. Any of the standard neuro-offensive viruses are also on the list - HIV, EBV, CMV. Vaccines have also been implicated although it is very rare.

Epidemiology

• Incidence in Europe is about 1.2-1.9 per 100,000

we get about 20 cases per year in our unit in Teesside

Presentation

• Rather than thinking of it as a cluster of symptoms, think about it as an acute peripheral neuropathy. So, symptoms can be;
  • Motor: weakness
  • Sensory: pain, paraesthesia, numbness
• Bulbar muscles might be involved. This could present as dysarthria or dysphagia.
• The worrying thing about this condition is that it could involve respiratory muscles and result in respiratory failure

sensory symptoms are more common than sensory signs. It is way more a motor than a sensory neuropathy (usually). The pattern of weakness can be proximal, distal or global and can be mild, moderate or severe.

When do you consider GBS as a potential diagnosis?

• Any acute (progression in days/weeks) presentation of motor symptoms (weakness), usually following an infection, should make you think about the condition.

loving this little video - it's for kids, but I'm older than you and you all look like kids to me!

here is also a nice lecture on GBS - not mine! Hope the lecturer doesn't mind.

Investigations

• Spirometry: consider FVC as this is a good measure of respiratory muscle strength. If weak, might need admission to ICU and artificial ventilation (do not do an peak flow!)
• ECG: GBS can cause autonomic neuropathy resulting in BP changes (hypo or hyper) and cardiac arrhythmias which might need attention.
• Antibody screen: this is sometimes done to look at antibodies which might be positive in certain variants of GBS. For example,
  • Miller Fisher syndrome: inflammatory neuropathy affecting cranial nerves resulting in ophthalmoplegia + ataxia + areflexia but (usually) not limb weakness. This will show positive anti-GQ1b antibody
    • Bickerstaff brainstem encephalitis: variant of Miller Fisher with additional drowsiness and extensor plantar responses (CNS involvement).
    • NB: some presentations of AIDP (the classical GBS) can have features of Miller Fisher with weakness. So, clinically, these different variants are hard to distinguish
  • Acute motor and sensory axonal neuropathy (AMSAN): associated with antibodies GM1, GM1b and GD1a.
  • Acute motor axonal neuropathy (AMAN): associated with antibodies GM1, GM1b, GD1a and GaINac-GD1a.
• Nerve conduction studies: should show a demyelinating picture.
• Lumbar puncture: classically there is elevated protein count and wcc are often normal (<5cells/mmcubed). If higher, consider alternate diagnosis including;
  • HIV infection (seroconversion)
  • Lyme disease
  • Malignancy (lymphoma)
• Immunoglobulin levels: this is done because patients with immunoglobulin deficiency will develop anaphylaxis when IVIG, which is one of the treatments for GBS
• CK: do this investigation in any weakness presentation to ensure you are not missing out a possible myopathy

don't get hung up on the antibody subtypes - if you remember nothing else, "ABC", FVC, Basic bloods, LP and NCS.

Management

• Monitor FVC
• If there is bulbar dysfunction, or there is VC compromise, consult ICU and admit if deterioration;
  • Ventilation/intubation (and NG tube for feeding after SALT consultation)
• Symptomatic: pain relief
• Immunological treatments
  • Intravenous immunoglobulin (IVIG)
  • Plasma exchange
• Prophylaxis
  • DVT: LMWH
  • Physiotherapy: to prevent joint stiffness and contractures, and aid turning to prevent pressure sores.
  • Constipation: often secondary to immobility and might necessitate laxative treatment
  • Depression: could occur, and if present might need treatment.

Prognosis

• 80% recover, but the time to recovery can be many months, complicated by pain, anxiety and depression.
• Mortality rate tends to be 3-7%. Death is often due to;
  • Respiratory failure
  • PE
  • Infection

References

• Ginsberg, L. (2011) Lecture Notes: Neurology
• Manji, H. e. a. (2014) Oxford Handbook of Neurology
• Patient (2016) Guillain-Barré Syndrome
• Peripheral nerve diseases (2008). Hughes. Practical Neurology. link.
• The University of Chicago (2017) Types of Peripheral Neuropathy – Inflammatory
• Mimics and chameleons in Guillain–Barré and Miller Fisher syndromes. (2015) Wakerley & Yuki. Practical Neurology. link.