What is the diagnosis and treatment for a patient presenting with symptoms suggestive of Guillain-Barré Syndrome (GBS)?

Guillain-Barré Syndrome: Diagnosis and Treatment

Guillain-Barré Syndrome (GBS) should be diagnosed based on characteristic clinical features and treated promptly with intravenous immunoglobulin (IVIG) 0.4 g/kg/day for 5 consecutive days or plasma exchange in patients unable to walk unaided. 1, 2

Clinical Presentation and Diagnosis

Typical Presentation

• Rapidly progressive bilateral weakness of legs and/or arms
• Progression typically reaches maximum within 2 weeks (if <24 hours or >4 weeks, consider alternative diagnoses)
• Decreased or absent reflexes in most patients
• Distal paresthesias or sensory loss often preceding weakness
• Pain (muscular, radicular, or neuropathic) is common
• Dysautonomia (blood pressure/heart rate instability, pupillary dysfunction, bowel/bladder issues) 3

Diagnostic Workup

1. Lumbar puncture: Look for albumino-cytological dissociation (elevated protein with normal cell count) 1
2. Electrophysiological studies: Help distinguish between subtypes:
   • AIDP (demyelinating) - most common in Western countries
   • AMAN (motor axonal)
   • AMSAN (sensorimotor axonal) 1
3. MRI spine: Consider to rule out compressive lesions in atypical cases 1
4. Anti-ganglioside antibody testing: Limited value in typical GBS but useful for Miller Fisher variant (anti-GQ1b) 1

Treatment Algorithm

First-Line Treatment

• For patients unable to walk unaided within 2-4 weeks of symptom onset:
  • IVIG: 0.4 g/kg/day for 5 consecutive days (total 2 g/kg) OR
  • Plasma exchange: 12-15 L in 4-5 exchanges over 1-2 weeks 1, 2
  • IVIG is generally preferred due to greater availability and lower complication rates 1

Treatment Considerations

• Do not use:
  • Second IVIG course in patients with poor prognosis
  • Oral or IV corticosteroids
  • Combination therapy (plasma exchange followed by IVIG) 2
• For pain management: Use gabapentinoids, tricyclic antidepressants, or carbamazepine 1, 2
• Monitor for treatment-related fluctuations (TRFs): Occur in 6-10% of patients within 2 months of treatment 3, 4

Respiratory Monitoring

• Apply the "20/30/40 rule" for respiratory monitoring:
  • Vital capacity < 20 ml/kg
  • Maximum inspiratory pressure < 30 cmH₂O
  • Maximum expiratory pressure < 40 cmH₂O
  • Single breath count ≤ 19 1
• Consider using Erasmus GBS Respiratory Insufficiency Score (EGRIS) to identify patients at risk of requiring mechanical ventilation 1

Prognosis

• Mortality rate: 3-10% despite optimal care 1, 4
• Approximately 80% of patients regain independent walking by 6 months 3, 4
• Use modified Erasmus GBS outcome score (mEGOS) to predict recovery of walking ability 1, 2
• Long-term residual complaints are common:
  • Pain
  • Weakness
  • Fatigue 3, 4
• Recovery can continue >3 years after onset 3
• Recurrence is rare (2-5%) 3

Important Pitfalls to Avoid

1. Delayed diagnosis: Be aware of atypical presentations, especially in children who may present with nonspecific features like poorly localized pain or refusal to bear weight 3
2. Missing variant forms: Recognize variants like Miller Fisher syndrome (ophthalmoplegia, areflexia, ataxia) and pure motor forms 3
3. Misdiagnosis of CIDP: About 5% of patients initially diagnosed with GBS develop chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with acute onset (A-CIDP), characterized by progression beyond 8 weeks or ≥3 TRFs 3, 4
4. Inadequate respiratory monitoring: Failure to monitor respiratory function can lead to emergency intubation and worse outcomes 1
5. Overlooking autonomic dysfunction: Can lead to cardiovascular complications, a major cause of mortality 3