Treatment Outcomes for GBS Based on Time from Onset
Both IVIg and TPE are equally effective for GBS patients presenting within 2 weeks of symptom onset, with no significant outcome differences between the two treatments during this critical window. 1, 2 However, treatment initiated after 4 weeks from onset is unlikely to provide benefit, as patients have typically reached the plateau phase and the acute inflammatory period has resolved. 1, 3
Treatment Window and Efficacy
Early Treatment (< 2 weeks from onset)
The 2-week window is the critical treatment period, as most GBS patients reach maximum disability within 2 weeks of onset, defining when immunotherapy can modify disease course. 1, 3
IVIg (0.4 g/kg daily for 5 days) and TPE (200-250 ml plasma/kg over 5 sessions) demonstrate equivalent efficacy when initiated within 14 days of neuropathic symptom onset. 1, 2
A landmark randomized trial of 379 patients treated within 14 days showed mean improvement of 0.9 grades for PE versus 0.8 grades for IVIg at 4 weeks, with differences so small that a 0.5 grade difference was excluded at 95% confidence. 2
No significant differences exist between IVIg and TPE for: time to recovery of unaided walking, time to discontinuation of ventilation, or disability recovery trends up to 48 weeks. 2
Late Treatment (2-4 weeks from onset)
Patients reaching maximum disability after 4 weeks should prompt consideration of alternative diagnoses rather than typical GBS. 1
Treatment after the plateau phase provides minimal additional benefit, as the inflammatory process has resolved and recovery depends on axonal regeneration rather than immunomodulation. 3
The therapeutic effect of both IVIg and TPE is not permanent—they provide acute immunomodulatory benefit during active inflammation, but cannot reverse established nerve damage. 3
Practical Treatment Selection
IVIg is Generally Preferred First-Line
IVIg is easier to administer, more widely available, and has significantly higher completion rates compared to TPE. 1, 4
The risk of treatment discontinuation is significantly lower with IVIg (RR: 0.22; 95% CI: 0.06-0.88) compared to TPE. 5
IVIg requires no special equipment or vascular access considerations, making it practical in most clinical settings. 1
Consider TPE in Specific Scenarios
Axonal subtypes (AMAN) with unexcitable nerves on EMG may respond better to TPE than IVIg, particularly in patients who have failed initial IVIg treatment. 6
Three patients with axonal involvement who failed IVIg showed improvement with subsequent TPE in one case series. 6
TPE should be considered for severe GBS requiring mechanical ventilation, using 4-6 sessions (4 sessions are effective; 6 provide no additional benefit). 3, 7
Treatment-Related Fluctuations
6-10% of patients experience treatment-related fluctuations (TRFs) within 2 months following initial improvement, indicating the treatment effect has worn off while inflammation continues. 4, 3, 8
TRFs require repeat treatment with a full course of IVIg or TPE, though evidence supporting this practice is limited. 4, 3
Distinguish TRFs from insufficient initial response: approximately 40% of patients show no improvement in the first 4 weeks, which does not indicate treatment failure. 4, 3
Critical Pitfall to Avoid
Do not confuse treatment timing with treatment choice. The question of IVIg versus TPE is only relevant within the first 2 weeks of symptom onset—after this window, the issue is not which treatment to choose, but whether any immunotherapy will provide benefit at all. 1, 3 Patients presenting between 2-4 weeks are approaching or past the plateau phase, where treatment efficacy diminishes regardless of modality selected.
Monitoring During Treatment Window
Assess respiratory function using the "20/30/40 rule": vital capacity <20 ml/kg, maximum inspiratory pressure <30 cmH₂O, or maximum expiratory pressure <40 cmH₂O indicates risk of respiratory failure. 4, 7
Single breath count ≤19 predicts requirement for mechanical ventilation. 4
Approximately 20% of GBS patients require mechanical ventilation within the first week regardless of treatment choice. 1, 7