How is Guillain-Barré syndrome diagnosed and treated?

Diagnosis and Treatment of Guillain-Barré Syndrome

Guillain-Barré syndrome (GBS) is diagnosed through clinical features, CSF examination, and electrodiagnostic studies, and should be treated with intravenous immunoglobulin (IVIg) at 0.4 g/kg/day for 5 days or plasma exchange (PE) for patients unable to walk unaided within 2-4 weeks of symptom onset. 1, 2

Diagnostic Approach

Clinical Features

• Progressive bilateral weakness of arms and legs (may initially involve only legs)
• Absent or decreased tendon reflexes in affected limbs
• Relative symmetry of symptoms and signs
• Progression phase lasting from days to 4 weeks (usually <2 weeks)
• Mild sensory symptoms (absent in pure motor variant)
• Cranial nerve involvement, especially bilateral facial palsy
• Autonomic dysfunction
• Absence of fever at onset 3, 1

Laboratory Investigations

1. Cerebrospinal Fluid (CSF) Examination:

   • Look for albumino-cytological dissociation (elevated protein with normal cell count)
   • Note: Protein levels may be normal in 30-50% of patients in the first week and 10-30% in the second week 3, 1
   • Marked pleocytosis (>50 cells/μl) suggests alternative diagnoses

2. Electrodiagnostic Studies:

   • Reveals sensorimotor polyradiculoneuropathy or polyneuropathy
   • Findings include reduced conduction velocities, reduced sensory and motor evoked amplitudes, abnormal temporal dispersion
   • "Sural sparing pattern" is typical (normal sural sensory nerve action potential with abnormal median/ulnar potentials)
   • May be normal early in disease course (within 1 week) 3
   • Helps differentiate subtypes: AIDP, AMAN, and AMSAN 3

3. Additional Tests:

   • Complete blood count, glucose, electrolytes, kidney function, liver enzymes
   • Anti-ganglioside antibodies (limited value in typical GBS but anti-GQ1b antibodies found in up to 90% of Miller Fisher syndrome cases) 3, 1
   • Nodal-paranodal antibodies when autoimmune nodopathy is suspected 2

4. Imaging:

   • MRI or ultrasound imaging in atypical cases
   • Nerve root enhancement on gadolinium-enhanced MRI can support diagnosis 3

Treatment Algorithm

Initial Management

1. Assess Severity and Progression:

   • Determine if patient can walk unaided
   • Evaluate respiratory function (vital capacity, signs of respiratory distress)
   • Monitor for autonomic dysfunction

2. ICU Admission Criteria 3:

   • Evolving respiratory distress with imminent respiratory insufficiency
   • Severe autonomic cardiovascular dysfunction
   • Severe swallowing dysfunction or diminished cough reflex
   • Rapid progression of weakness

Specific Immunotherapy

1. First-line Treatment Options:

   • Intravenous Immunoglobulin (IVIg):

     • Dosage: 0.4 g/kg/day for 5 consecutive days
     • Indicated for patients unable to walk unaided within 2 weeks of symptom onset (can be considered up to 4 weeks) 1, 2

   • Plasma Exchange (PE):

     • Dosage: 12-15 L in 4-5 exchanges over 1-2 weeks
     • Effective when initiated within 4 weeks of symptom onset 1, 2

2. Treatment Considerations:

   • IVIg is generally preferred for practical reasons 4
   • A second IVIg course is not recommended for patients with poor prognosis 2
   • PE followed immediately by IVIg is not recommended 2
   • Corticosteroids are not recommended as monotherapy 1, 2

Supportive Care

1. Pain Management:

   • Consider gabapentinoids, tricyclic antidepressants, or carbamazepine 1, 2

2. Respiratory Support:

   • Regular monitoring of vital capacity
   • Elective intubation for impending respiratory failure
   • Consider using modified Erasmus GBS Respiratory Insufficiency Score (mEGRIS) to assess ventilation risk 2

3. Prevention of Complications:

   • Deep vein thrombosis prophylaxis
   • Pressure ulcer prevention
   • Early physiotherapy and rehabilitation

Monitoring and Prognosis

• About 60-80% of patients can walk independently 6 months after onset 1
• Approximately 20% remain unable to walk after 6 months 1
• Mortality rate is 3-10% despite optimal treatment 1
• Recovery can continue for more than 3 years after onset 1

Poor Prognostic Factors

• Advanced age
• Rapid progression of symptoms
• Need for mechanical ventilation
• Severe axonopathy on electrophysiological studies 1

Special Considerations

• Consider changing diagnosis to acute-onset chronic inflammatory demyelinating polyradiculoneuropathy (A-CIDP) if progression continues after 8 weeks from onset (occurs in ~5% of patients) 2
• About 10% of GBS patients have secondary deterioration within 8 weeks after starting IVIg (treatment-related fluctuation), requiring repeated IVIg 4

Common Pitfalls and Caveats

• Don't delay treatment waiting for antibody test results 3
• Normal CSF protein levels early in the disease course do not rule out GBS 3
• Pain can precede weakness and cause diagnostic confusion 4
• Electrodiagnostic studies may be normal early in the disease course 3
• Consider alternative diagnoses in patients with marked CSF pleocytosis or atypical progression 3