Guillain-Barre syndrome (GBS)

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management

Definition

Guillain-Barré syndrome (GBS) is an acute, immune-mediated polyneuropathy characterised by progressive weakness and areflexia, often triggered by a preceding infection.

Aetiology

GBS is caused by an autoimmune response that attacks the peripheral nervous system, often following an infection.

Common Triggers:

  • Viral or bacterial infections: most commonly Campylobacter jejuni, but also influenza, cytomegalovirus (CMV), Epstein-Barr virus (EBV), and Mycoplasma pneumoniae.
  • Vaccination: rarely associated with influenza or COVID-19 vaccines.
  • Post-surgical state: can trigger an immune response leading to GBS.

Pathophysiology

  • Molecular mimicry leads to autoantibodies attacking the myelin sheath of peripheral nerves.
  • Results in demyelination and, in severe cases, axonal damage.
  • Slows nerve conduction, causing progressive muscle weakness and paralysis.

Risk factors

  • Recent bacterial or viral infection (especially Campylobacter jejuni).
  • Post-vaccination immune response (rare).
  • Older age.
  • Male sex.
  • History of autoimmune conditions.

Signs and symptoms

GBS typically presents with ascending weakness and sensory disturbances.

Early Symptoms:

  • Progressive weakness starting in the legs and spreading upwards.
  • Paresthesia (tingling or numbness) in hands and feet.
  • Back pain or muscle aches.

Progressive Symptoms:

  • Areflexia: loss of deep tendon reflexes.
  • Flaccid paralysis: can progress to total limb paralysis.
  • Autonomic dysfunction: blood pressure fluctuations, urinary retention, arrhythmias.
  • Respiratory failure: weakness of the diaphragm requiring ventilatory support in severe cases.

Severe Features (Life-Threatening):

  • Bulbar involvement: difficulty swallowing, speaking, risk of aspiration.
  • Respiratory muscle weakness: risk of respiratory failure.
  • Severe autonomic instability: bradycardia, hypertension, cardiac arrhythmias.

Investigations

  • Clinical diagnosis: based on progressive weakness and areflexia.
  • Lumbar puncture: raised cerebrospinal fluid (CSF) protein with normal white cell count ("albuminocytologic dissociation").
  • Nerve conduction studies (NCS): shows slowed conduction velocity and demyelination.
  • Electromyography (EMG): confirms peripheral nerve involvement.
  • Serology: consider testing for recent Campylobacter jejuni or viral infections.
  • Respiratory function tests: monitor for impending respiratory failure (e.g., vital capacity assessment).

Management

1. Supportive Care:

  • Admit to a high-dependency unit (HDU) if respiratory or autonomic involvement.
  • Regular monitoring of respiratory function (forced vital capacity, FVC).
  • Thromboprophylaxis (e.g., enoxaparin) due to immobility.
  • Catheterisation if urinary retention develops.

2. Specific Treatment:

  • Plasma exchange: first-line in severe cases to remove circulating autoantibodies.
  • Intravenous immunoglobulin (IVIG): alternative to plasma exchange.
  • No role for corticosteroids (not effective in GBS).

3. Respiratory Support:

  • Intubation and mechanical ventilation if FVC <15 mL/kg or respiratory distress.

4. Rehabilitation:

  • Physiotherapy to prevent contractures and improve mobility.
  • Occupational therapy for adaptive strategies.
  • Speech therapy if bulbar weakness affects swallowing.

5. Long-Term Monitoring:

  • Recovery typically takes weeks to months.
  • Up to 20% have residual weakness at 1 year.
  • Monitor for chronic inflammatory demyelinating polyneuropathy (CIDP), a chronic variant.
NeurologymypanotesGuillain-Barre syndrome (GBS)