Updated October 2025
Neuromuscular Emergencies
Guillain–Barré Syndrome (GBS) and Other Acute Demyelinating Neuropathies
GBS is the most common cause of acute flaccid paralysis worldwide. Early recognition of ascending weakness, areflexia, and autonomic risk, followed by timely IVIg or plasma exchange, improves outcomes. Miller Fisher syndrome (MFS) is often mild and self-limited, while axonal variants carry worse prognosis. Prompt respiratory and autonomic monitoring are essential to prevent morbidity.
Clinical question
How should clinicians recognize, risk-stratify, and treat Guillain–Barré syndrome and related acute demyelinating neuropathies to optimize short- and long-term outcomes?
GBSAIDPAMAN/AXONALMFSCIDPIVIgPlasma exchangeNeuromuscular respiratory failure
Key points
Recognize the phenotype
Rapidly progressive, symmetrical weakness with areflexia; back/neuropathic pain, facial diplegia, dysautonomia, and sensory symptoms are common. Consider variants: AIDP, AMAN/axonal forms, and MFS (ophthalmoplegia-ataxia-areflexia) [3], [4], [5].
Monitor for respiratory failure
Serial FVC, NIF, and bulbar assessment; early ICU transfer when FVC <20 mL/kg, rapid decline, or bulbar/autonomic involvement. Early treatment improves outcomes [5], [6].
Initiate disease-modifying therapy
IVIg or plasma exchange are the only proven effective therapies; start as early as possible when nonambulant or rapidly progressive [6], [7], [2].
Confirm and classify
CSF albuminocytologic dissociation (often after day 7), and electrodiagnostics to distinguish demyelinating vs axonal variants and to inform prognosis [4], [5].
Set expectations
Most recover substantially, but residual deficits and fatigue are frequent. Persistent or relapsing weakness beyond 8 weeks suggests CIDP spectrum and requires re-evaluation [3], [5], [2].
Evidence highlights
0.6–1.9 per 100,000/year [1]
Incidence (NA/EU)
≈20% despite therapy [2]
Unable to walk at 6 months
≈2–10% in modern series [2]
Mortality
Near-complete recovery ≤6 months, often without treatment [3]
Prognosis in pure MFS
Diagnosis, Risk Stratification, and Initial Management
Early diagnosis and treatment mitigate respiratory failure, dysautonomia, and long-term disability.
1
Recognize core features and exclude mimics
Look for rapidly progressive, relatively symmetric limb weakness with areflexia over hours to 4 weeks, often following infection. Red flags for alternative diagnoses include marked asymmetry, hyperreflexia with spasticity, sensory level, or sphincter disturbance. MFS presents with ophthalmoplegia, ataxia, and areflexia, typically with anti-GQ1b positivity and a benign course [3], [5].
2
Baseline tests and monitoring
Obtain CSF (protein elevation with ≤10 cells/µL after first week) and electrodiagnostics (reduced CMAPs, demyelinating conduction slowing/block in AIDP; low CMAP without slowing in axonal variants). Monitor FVC, NIF, bulbar function, and autonomic signs every 4–6 hours if moderate–severe [4], [5].
3
When to treat
Initiate therapy in nonambulant patients, those with rapid progression, bulbar or autonomic involvement, or declining respiratory metrics. Earlier IVIg is associated with better outcomes; timing is a modifiable prognostic factor (earlier is better) [6].
4
Choose therapy
Either IVIg (2 g/kg total over 2–5 days) or plasma exchange (4–5 exchanges over ~7–14 days) are effective; do not combine routinely. Corticosteroids are not effective in classic GBS. Refractory cases may need retreatment or trial enrollment; novel immunomodulatory approaches are under investigation [7], [2].
5
Supportive care to prevent complications
DVT prophylaxis, pain control (neuropathic agents), bowel/bladder care, pressure-sore prevention, and early PT/OT are critical. Vigilantly manage dysautonomia (arrhythmias, BP lability). Consider early intubation for rapid decline or bulbar dysfunction [5], [2].
Phenotypes, Prognosis, and Treatment Pearls
Use this grid to differentiate variants, anticipate course, and fine-tune therapy.
GBS Variants and Typical Course
AIDP (Europe/NA predominant): demyelinating features; sensory symptoms frequent; recovery usually favorable with therapy [4], [5].
AMAN/axonal: faster progression, more severe weakness; worse short-term prognosis, lower CMAPs; recovery may be prolonged [4], [5].
MFS: ophthalmoplegia–ataxia–areflexia; anti-GQ1b common; generally mild with near-complete recovery ≤6 months, often without treatment [3].
Epidemiology and Outcomes
Incidence 0.6–1.9 per 100,000/year in NA/EU; male predominance [1].
Despite treatment: mortality ≈2–10%; ≈20% unable to walk at 6 months; many with residual fatigue/neuropathic pain [2].
Most severe cases recover substantially over months; counseling on realistic timelines is essential [8].
Diagnostics That Shift Management
CSF: albuminocytologic dissociation typically after day 7; pleocytosis >50 suggests alternative/infectious etiologies [5].
Electrodiagnostics: classify demyelinating vs axonal; absent H-reflexes early support radiculopathy; reduced SNAPs/CMAPs support peripheral neuropathy [5].
Serologies: consider anti-GQ1b in MFS; infectious work-up guided by history [5].
Timing and Choice of Immune Therapy
Start treatment promptly when criteria met; earlier IVIg initiation is linked to improved outcomes (functional recovery) [6].
IVIg and plasma exchange are the only proven effective immune treatments over the last 30 years [7], [2].
Routine combination or steroids in classic GBS are not recommended; consider retreatment in selected nonresponders [2].
Red Flags and Pitfalls
Do not delay treatment while waiting for CSF/EMG if clinically clear and progressing.
Watch for dysautonomia: malignant hypertension/hypotension and arrhythmias can be fatal; continuous monitoring in moderate–severe disease [5], [2].
Differentiate acute-onset CIDP if deterioration continues beyond 8 weeks or with relapses; management shifts to CIDP regimens [9], [10], [11].
Long-term Care and Transition
Rehabilitation, fatigue management, neuropathic pain therapy, and mental health support.
Assess for treatment-related fluctuations; consider CIDP workup if relapse or progression beyond expected GBS window [9], [10], [11].
Patient-reported outcome measures can track disability, pain, fatigue, and quality of life through recovery [11].
References
Source material
Primary literature that informs this article.
Acute Inflammatory Demyelinating Polyneuropathy
www.sciencedirect.com
Treatment dilemmas in Guillain-Barré syndrome
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Diagnosis and management of Guillain–Barré syndrome ...
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Early prognostic factors in acute inflammatory ...
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Guillain‐Barré syndrome: a comprehensive review - Bellanti
onlinelibrary.wiley.com
Timing of intravenous immunoglobulin treatment and ...
onlinelibrary.wiley.com
New insights in the immune treatment of Guillain–Barré...
journals.lww.com
Guillain–Barré syndrome
www.who.int
diagnostic and therapeutic challenges for a treatable ...
www.sciencedirect.com
Chronic inflammatory demyelinating polyneuropathy as an ...
www.sciencedirect.com
Patient‐Reported Outcome Measures for Assessing Health ...
onlinelibrary.wiley.com
Guillain-Barré syndrome and chronic inflammatory ...
www.uptodate.com