What is the treatment approach for Guillain-Barré Syndrome (GBS) with pure motor polyneuropathy on nerve conduction studies?

Treatment of Guillain-Barré Syndrome with Pure Motor Polyneuropathy

Intravenous immunoglobulin (IVIg) at a dose of 0.4 g/kg body weight daily for 5 days is the first-line treatment for Guillain-Barré Syndrome with pure motor polyneuropathy. 1

First-Line Treatment Options

• IVIg is preferred over plasma exchange as first-line therapy because it is easier to administer, more widely available, and has higher completion rates 1
• Treatment should be initiated as early as possible in the disease course to maximize effectiveness 1
• The 5-day IVIg regimen is preferred over a shorter 2-day regimen, as treatment-related fluctuations are more frequent with the shorter regimen 2
• Plasma exchange (200-250 ml/kg over 5 sessions) is an effective alternative when IVIg is contraindicated, not tolerated, or unavailable 1, 3
• Corticosteroids alone are not recommended for GBS treatment as they have shown no significant benefit and may even have negative effects on outcomes 1, 2

Patient Assessment and Monitoring

• Regular respiratory function assessment is essential using the "20/30/40 rule": patient is at risk of respiratory failure if vital capacity <20 ml/kg, maximum inspiratory pressure <30 cmH₂O, or maximum expiratory pressure <40 cmH₂O 1
• Monitor for single breath count (a count of ≤19 predicts requirement for mechanical ventilation), use of accessory respiratory muscles, and ability to cough 2
• About 20% of patients with GBS develop respiratory failure and require mechanical ventilation 4
• Autonomic dysfunction should be monitored via electrocardiography, heart rate, blood pressure, and bowel/bladder function 2
• Cardiac arrhythmias and blood pressure instability can occur due to autonomic nervous system involvement 4

Management of Disease Progression

• About 40% of patients do not show improvement in the first 4 weeks following treatment, which doesn't necessarily indicate treatment ineffectiveness 4
• Treatment-related fluctuations (TRFs) occur in 6-10% of patients within 2 months of initial improvement 4
• For patients with TRFs, repeating the full course of IVIg or plasma exchange is common practice, although evidence supporting this approach is limited 4, 5
• In approximately 5% of cases initially diagnosed as GBS, the diagnosis may change to acute-onset chronic inflammatory demyelinating polyneuropathy (A-CIDP) if repeated relapses occur 4

Supportive Care and Complication Management

• Multidisciplinary supportive care is crucial and should include pain management, as pain is common in GBS patients 2
• Prevention of pressure ulcers, hospital-acquired infections (pneumonia, urinary tract infections), and deep vein thrombosis is essential 2
• Psychological support for anxiety, depression, and hallucinations which are frequent in GBS patients is crucial 4
• Avoid medications that can worsen neuromuscular function, such as β-blockers, IV magnesium, fluoroquinolones, aminoglycosides, and macrolides 1

Prognosis and Follow-up

• About 80% of patients regain walking ability at 6 months after disease onset 4
• Mortality occurs in 3-10% of cases, most commonly due to cardiovascular and respiratory complications 4
• Long-term residual complaints can include neuropathic pain, weakness, and fatigue 5
• Recovery can continue for more than 5 years after disease onset 4
• Recurrence of GBS is rare (2-5%) but still higher than the lifetime risk in the general population (0.1%) 4

Special Considerations for Pure Motor Polyneuropathy

• Pure motor variants (acute motor axonal neuropathy - AMAN) may have a different immunopathological mechanism than classic GBS 4
• The same treatment approach with IVIg or plasma exchange applies to pure motor variants 1
• Regular follow-up is necessary to monitor for long-term complications and ensure complete recovery 2
• A rehabilitation program with a rehabilitation specialist, physiotherapist, and occupational therapist is crucial for recovery 5