What are the basic presentation, evaluation, and treatment of Guillain-Barré Syndrome (GBS)?

Guillain-Barré Syndrome: Presentation, Evaluation, and Treatment

Guillain-Barré syndrome (GBS) is a potentially fatal immune-mediated disease of the peripheral nerves requiring prompt diagnosis and treatment with either intravenous immunoglobulin or plasma exchange to improve mortality and morbidity outcomes. 1

Clinical Presentation

Typical Features

• Classic presentation: Rapidly progressive bilateral weakness of legs and/or arms, ascending from distal to proximal
• Sensory symptoms: Distal paresthesias or sensory loss, often preceding or accompanying weakness
• Reflexes: Decreased or absent in most patients at presentation, almost all at nadir
• Time course: Maximum disability typically reached within 2 weeks of onset
• Pain: Frequently reported (muscular, radicular, or neuropathic)
• Autonomic dysfunction: Blood pressure/heart rate instability, pupillary dysfunction, bowel/bladder dysfunction 1

Atypical Presentations

• Asymmetrical weakness (though always bilateral)
• Predominantly proximal or distal weakness
• Weakness starting in arms, legs, or simultaneously
• Severe diffuse pain preceding weakness
• Isolated cranial nerve dysfunction
• In children <6 years: poorly localized pain, refusal to bear weight, irritability, meningism, unsteady gait 1

Clinical Variants

• Pure motor variant (weakness without sensory signs)
• Cranial nerve variant (bilateral facial palsy with paresthesias)
• Pharyngeal-cervical-brachial weakness (upper limb predominant)
• Paraparetic variant (lower limb predominant)
• Miller Fisher syndrome (ophthalmoplegia, areflexia, ataxia) 1, 2

Preceding Events

• Approximately two-thirds of patients report infection in the 6 weeks preceding onset
• Common triggers: Campylobacter jejuni, cytomegalovirus, Epstein-Barr virus, Mycoplasma pneumoniae 1, 3

Diagnostic Evaluation

Key Diagnostic Steps

1. Clinical assessment: Rapidly progressive bilateral weakness with or without sensory symptoms

2. CSF examination:

   • Classic finding: Albuminocytological dissociation (elevated protein with normal cell count)
   • May be normal early in disease course (first week) 1, 2

3. Electrophysiological studies:

   • Provides evidence of peripheral nervous system dysfunction
   • Helps distinguish between subtypes:
     • Acute inflammatory demyelinating polyradiculoneuropathy (AIDP) - most common in Western countries
     • Acute motor axonal neuropathy (AMAN) - more common in East Asia
     • Acute motor sensory axonal neuropathy (AMSAN) 1, 3

4. Additional testing:

   • Anti-ganglioside antibodies (limited value in typical GBS, but useful when Miller Fisher syndrome is suspected)
   • Nodal-paranodal antibodies when autoimmune nodopathy is suspected
   • MRI or ultrasound imaging in atypical cases 2

Differential Diagnosis

• Consider alternative diagnoses if:
  • Maximum disability reached within 24 hours or after 4 weeks
  • Marked persistent asymmetry
  • Severe bowel or bladder dysfunction at onset
  • CNS involvement
  • Acute-onset CIDP (progression continues after 8 weeks from onset) 1, 2

Treatment

Supportive Care

• Respiratory monitoring: All patients require close monitoring of respiratory function
  • 20% develop respiratory failure requiring mechanical ventilation
  • Respiratory failure can occur without symptoms of dyspnea 1
• Autonomic monitoring: Heart rate, blood pressure, pupillary function
• Venous thromboembolism prophylaxis
• Pain management: Gabapentinoids, tricyclic antidepressants, or carbamazepine 2

Immunotherapy

• Intravenous immunoglobulin (IVIg):

  • Recommended dose: 0.4 g/kg daily for 5 consecutive days
  • Indicated for patients within 2-4 weeks after onset of weakness who are unable to walk unaided 1, 2

• Plasma exchange (PE):

  • Recommended regimen: 200-250 ml/kg in 4-5 exchanges over 1-2 weeks
  • Indicated for patients within 4 weeks after onset of weakness who are unable to walk unaided 1, 2

• Important treatment notes:

  • IVIg and PE are equally effective
  • Second IVIg course is not recommended for patients with poor prognosis
  • Corticosteroids alone are not effective and not recommended
  • Combined PE followed immediately by IVIg is not recommended 1, 2

Treatment of Complications

• Intensive care management for respiratory failure
• Management of autonomic dysfunction
• Pain control
• Prevention of deep vein thrombosis
• Early rehabilitation 1

Prognosis

• Mortality: 3-10% despite best medical care 1
• Recovery timeline:
  • 60-80% of patients able to walk independently 6 months after onset
  • Most improvement occurs in first year but can continue for >5 years 1, 4
• Prognostic tools:
  • Modified Erasmus GBS Outcome Score (mEGOS) to assess outcome
  • Modified Erasmus GBS Respiratory Insufficiency Score (mEGRIS) to assess risk of requiring artificial ventilation 2
• Recurrence: Rare (2-5% of patients) 1, 4

Important Clinical Pitfalls

• Failure to recognize atypical presentations, especially in children
• Overlooking respiratory insufficiency (can occur without dyspnea)
• Missing autonomic dysfunction which contributes to mortality
• Confusing treatment-related fluctuations (TRF) with disease progression
• Misdiagnosing acute-onset CIDP (A-CIDP) as GBS (occurs in ~5% of initially diagnosed GBS patients) 1, 2, 4
• Delaying treatment beyond the therapeutic window (most effective within first 2-4 weeks) 2