Neuro emergencies

Guillain-Barré syndrome and myasthenic crisis

Reviewed Nov 2026·3 references
New· views rounded down, updated weekly

Neuromuscular respiratory failure creeps up silently: monitor vital capacity and NIF, intubate electively when VC < 20 mL/kg or NIF weaker than −30 cmH2O, or with bulbar failure. Treat GBS with IVIg or plasma exchange; myasthenic crisis with IVIg or PLEX plus steroids.

At the bedside

Timed steps
  1. 1

    20/30/40 rule

    Monitor

    Intubate if VC < 20 mL/kg, NIF (MIP) weaker than −30 cmH2O, MEP < 40 cmH2O, or rapid decline; bulbar weakness with aspiration. SpO2 and ABG change late.

  2. 2

    Predict

    GBS

    EGRIS (days from onset to admission, facial/bulbar weakness, MRC sum score): high score → ~65% need ventilation within a week; admit to ICU.

  3. 3

    Treat

    GBS

    Unable to walk unaided within 2 weeks of onset (4 weeks for PLEX): IVIg 0.4 g/kg/day × 5 days or plasma exchange 12-15 L over 4-5 exchanges. Steroids are not recommended.

  4. 4

    Dysautonomia

    GBS

    Labile BP and arrhythmias; avoid large BP-lowering doses; temporary pacing for severe bradycardia. DVT prophylaxis, pain control (gabapentinoids), bowel care.

  5. 5

    Treat

    Myasthenic crisis

    IVIg 2 g/kg over 2-5 days or PLEX (5 exchanges); start or continue corticosteroids (watch for early worsening); hold pyridostigmine while intubated. Look for trigger (infection, aminoglycosides, fluoroquinolones, magnesium, β-blockers).

  6. 6

    Mimics

    Exclude

    Hypokalaemia, hypophosphataemia, neurotoxic snakebite, OP poisoning (intermediate syndrome), botulism, transverse myelitis, diphtheria (still seen in India).

GBS or myasthenic crisis

Intravenous immunoglobulin (IVIg)

IV
Dose
0.4 g/kg/day for 5 days (2 g/kg total)
Worked example
60 kg: 24 g/day × 5 days
Red flag · call your senior now
Single breath count < 20, staccato speech, paradoxical breathing, weak cough: imminent respiratory failure.
Pitfall
Waiting for hypoxaemia or hypercapnia before intubating neuromuscular patients.
Pitfall
Using succinylcholine in GBS (hyperkalaemia).
Pearl
Small-volume plasma exchange is a cheaper option studied in India where IVIg is unaffordable.

References

  1. 1

    van Doorn PA, Van den Bergh PYK, Hadden RDM, et al. European Academy of Neurology/Peripheral Nerve Society guideline on diagnosis and treatment of Guillain-Barré syndrome. Eur J Neurol. 2023;30(12):3646-3674

  2. 2

    Walgaard C, Lingsma HF, Ruts L, et al. Prediction of respiratory insufficiency in Guillain-Barré syndrome. Ann Neurol. 2010;67(6):781-787

  3. 3

    Narayanaswami P, Sanders DB, Wolfe G, et al. International consensus guidance for management of myasthenia gravis: 2020 update. Neurology. 2021;96(3):114-122

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