An 'acute paralytic polyneuropathy' that affects the peripheral nervous system

Aetiology

• Usually demyelinating or occasionally axonal, and has an immune-mediated, often post-infectious, basis
  • Particularly associated with campylobacter jejuni, cytomegalovirus and Epstein-Barr virus

Pathophysiology

• Guillain-Barré is thought to occur due to a process called molecular mimicry
• The B cells of the immune system create antibodies against the antigens on the pathogen that causes the preceding infection
• These antibodies also match proteins on the nerve cells
• They may target proteins on the myelin sheath of the motor nerve cell or the nerve axon

Clinical features

Symptoms

• Symptoms usually start within 4 weeks of the preceding infection
• Symmetrical ascending weakness (starting at the feet and moving up the body)
• It may progress to the cranial nerves and cause facial nerve weakness

Signs

• Reduced reflexes
• There may be peripheral loss of sensation or neuropathic pain

Investigations

• Clinical diagnosis
• Can be supported by:
  • Nerve conduction studies
  • Lumbar puncture for CSF - will show raised protein with a normal cell count and glucose
• Bedside spirometry (FVC) monitoring essential due to risk of respiratory failure