EM · Neuromuscular junction disorders
Guillain-Barré syndrome and myasthenia gravis
Also known as Guillain-Barré syndrome · GBS · Acute inflammatory demyelinating polyradiculoneuropathy · AIDP · Myasthenia gravis · MG · Myasthenic crisis · Miller-Fisher syndrome
Guillain-Barré syndrome — the acute ascending flaccid paralysis with areflexia and autonomic instability, the respiratory-failure thresholds (FVC under 20 mL/kg or NIF under minus 30 cmH2O), the albuminocytologic dissociation on the CSF, and the IVIG 0.4 g/kg/day for 5 days or plasma exchange; and myasthenia gravis — the fatigable weakness (ptosis, diplopia, bulbar), the AChR antibody, the neostigmine and ice-pack tests, the pyridostigmine 60 mg PO, and the IVIG or plasma exchange for the myasthenic crisis. The GBS-versus-MG-versus-Lambert-Eaton differential. ACEM-primary, globally tagged.
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Target exams
Red flags
- The ascending flaccid paralysis with areflexia is Guillain-Barré until proven otherwise — measure the FVC and the NIF every 2 to 4 hours
- An FVC under 20 mL/kg, an NIF under minus 30 cmH2O, or a 30 per cent fall from baseline mandates ICU admission and probable intubation
- Autonomic instability in GBS can kill — cardiac monitoring for the arrhythmia and the blood-pressure swings; have atropine and the pacing ready
- GBS is not treated with corticosteroids — they are ineffective as monotherapy; use IVIG 0.4 g/kg/day for 5 days or plasma exchange, not both
- The early steroid-induced worsening of myasthenia gravis — start the IVIG or plasma exchange first, add the steroid with overlap, and protect the airway
- Aminoglycosides, macrolides, beta-blockers, magnesium and neuromuscular blockers precipitate the myasthenic crisis — avoid them
Meet the patient
A 54-year-old man arrives with four days of progressive weakness that began in his feet and has climbed to his thighs and hands. He had a diarrhoeal illness two weeks ago. He is areflexic in all four limbs, with bilateral facial weakness and a weak cough that cannot clear his drooling secretions. RR 24, SpO2 96 per cent on room air, FVC 22 mL/kg and falling.[1]
The patient talks and keeps his saturation until the FVC is critically low — the bedside appearance lies. Measure the FVC every 2 to 4 hours; the trend, not the snapshot, decides the airway.[2]
References10ShowHide
- [1]van den Berg B, Walgaard C, Drenthen J, et al. Guillain-Barré syndrome: pathogenesis, diagnosis, treatment and prognosis Nat Rev Neurol, 2014.PMID 25023340
- [2]Willison HJ, Jacobs BC, van Doorn PA. Guillain-Barré syndrome Lancet, 2016.PMID 26948435
- [3]Chevret S, Hughes RA, Annane D. Plasma exchange for Guillain-Barré syndrome Cochrane Database Syst Rev, 2017.PMID 28241090
- [4]Doets AY, Hughes RA, Brassington R, et al. Pharmacological treatment other than corticosteroids, intravenous immunoglobulin and plasma exchange for Guillain-Barré syndrome Cochrane Database Syst Rev, 2020.PMID 31981368
- [5]Lowie BJ Fluctuating, but Not Forgotten: Recognizing Neuromuscular Junction Disorders Emerg Med Clin North Am, 2026.PMID 41895886
- [6]Narayanaswami P, Sanders DB, Wolfe GI, et al. International Consensus Guidance for Management of Myasthenia Gravis: 2020 Update Neurology, 2021.PMID 33144515
- [7]Lacomis D. Myasthenic crisis Neurocrit Care, 2005.PMID 16377829
- [8]Motomura M, Ike K, Kitanosono H, et al. [How to Diagnose Lambert-Eaton Myasthenic Syndrome Patients Early: A Systematic Review of Japanese Case Reports]. Brain Nerve, 2026.PMID 41700072
- [9]Hughes RA, Swan AV, van Doorn PA. Intravenous immunoglobulin for Guillain-Barré syndrome Cochrane Database Syst Rev, 2014.PMID 25238327
- [10]van der Meché FG, Schmitz PI. A randomized trial comparing intravenous immune globulin and plasma exchange in Guillain-Barré syndrome N Engl J Med, 1992.PMID 1552913