Guillain Barre Syndrome

Guillain Barre Syndrome (GBS) is most usually triggered by a preceding infection, and results in acute weakness of muscles

Pathophysiology

• Campylobacter jejuni, Epstein-Barr virus and cytomegalovirus are well recognised causes of GBS.
• Infection with certain agents results in antibodies against peripheral nerves due to molecular mimicry.
• For example, the lipooligosaccharide component of C jejuni is similar to the ganglioside component of peripheral nerves, resulting in ganglioside antibodies that can target different parts of the nerve, such as the neuromuscular junctions, myelin sheaths or nodes of Ranvier.
• This results in damage to the peripheral nervous system, manifesting in various symptoms

Causes

• Previous gastrointestinal or respiratory infection
  • Campylobacter jejuni
  • Cytomegalovirus
  • Epstein-Barr virus
  • Haemophilus influenzae
  • Mycoplasma pneumoniae
• Surgery
• Trauma

Clinical Features

GBS is characteristically symmetrical and presents with acute flaccid paralysis. Signs and symptoms tend to reach a peak severity in four weeks, and then hit a plateau phase which can range from 2 days to 6 months, after which patients start to recover. Clinical features are in keeping with lower motor neuron pathology.

• Muscle Weakness:
  • Ascending: Usually starts in the legs before the arms
  • Usually affects proximal muscles first, then distal
• Flaccid Paralysis
• Hypotonia
• Hyporeflexia or Areflexia
• Facial weakness or paralysis: Involvement of the facial nerves
• Dysphagia and/or Difficulty Speaking: Involvement of hypoglossal, vagus and glossopharyngeal nerves
• Sensory symptoms i.e. paraesthesia which usually starts distally
• Back pain
• Dyspnoea or respiratory muscle weakness: Due to involvement of the diaphragm
• Autonomic dysfunction e.g. sweating, tachycardia, hypotension, hypertension

Clinical Variants

• Acute Inflammatory Demyelinating Polyneuropathy (AIDP)
  • Sensory and motor involvement
  • Pain
  • Cranial nerve involvement
  • Autonomic dysfunction

• Acute Motor Axonal Neuropathy (AMAN)
  • Purely motor form of GBS
  • Usually more rapid progression than AIDP
  • Recovery is also often longer in AIDP

• Miller Fisher Syndrome: Triad of ophthalmoplegia, areflexia and ataxia.

Investigations

• Nerve conduction studies
• Lumbar puncture: CSF protein is usually raised, with normal white cell count
• Spirometry: Forced vital capacity needs to be monitored - if it's going down, it suggests the diaphragm is becoming involved
• ABG: Looking for type 2 respiratory failures

Management

• Intravenous immunoglobulin: Thought to work by inhibiting the binding of nerve antibodies
• Plasma exchange: Thought to work by removing antibodies to nerves
• Pain management
• Regular monitoring of:
  • Forced vital capacity
  • Blood pressure
  • Heart rate
  • Potentially ABGs
• DVT prophylaxis
• Ventilation
• Patients may require rehabilitation following recovery

References

https://www.ncbi.nlm.nih.gov/books/NBK532254/

https://www.nature.com/articles/nrneurol.2014.121