Anesthesiology APPLIED Exam › Neuroanesthesia and neuromuscular

Multiple sclerosis, ALS and Guillain-Barré syndrome

Neuroanesthesia and neuromuscular·~4 min read· Physician-reviewed✓ Sourced · 6

Stem

A 66-year-old man, 82 kg, with amyotrophic lateral sclerosis diagnosed two years ago, fell and fractured his left femoral neck and is booked for a hemiarthroplasty. Weakness began in his legs; he now has mild dysarthria and coughs when drinking thin liquids. Forced vital capacity is 52% of predicted, and he uses BiPAP at night. He takes riluzole. Blood pressure 138/80, SpO2 94% on room air.

Question

What is your anesthetic plan?

Ideal answer

HeadlineSpinal anesthesia with light sedation is my first choice; succinylcholine never, and I plan his breathing after surgery before I start.

Settle goals first. Would he accept intubation or a tracheostomy if he cannot be extubated? Respiratory failure is how ALS kills.¹
Spinal plus a fascia iliaca block, BiPAP on hand, because it avoids relaxants and airway instrumentation; the fear of neuraxial worsening is contested, and I discuss it.¹
If general: rapid sequence with rocuronium, no succinylcholine. Upregulated receptors cause hyperkalemia, and bulbar weakness means aspiration risk.¹
Reduced nondepolarizer dose, quantitative monitoring, sugammadex, because these patients are sensitive and residual block will not be tolerated.¹^,2
Extubate fully awake onto BiPAP, monitored bed, with minimal opioid.

Watch for: rising CO2 with a normal saturation, a weak cough, pooled secretions.

Breaking down the answer

Succinylcholine across all three — denervation spreads acetylcholine receptors beyond the junction, so potassium surges; it is contraindicated in Guillain-Barré and best avoided in neuromuscular disease generally.³^,2 Changes if: never; rocuronium with sugammadex covers rapid sequence.
Neuraxial and MS relapse — a systematic review of 37 reports and 231 patients found no clear cause and effect;⁴ a 2025 review of 1,315 parturients found no rise in postpartum relapse, which tracks disease activity instead.⁵
What does trigger MS relapse — fever, infection and stress, so I keep him normothermic and treat infection.⁵
Guillain-Barré ventilation thresholds — vital capacity under 20 mL/kg, maximal inspiratory pressure weaker than 30 cmH2O, expiratory under 40, or a 30% fall.³
Who will need the ventilator — in 222 Guillain-Barré patients, 17% were ventilated; bulbar dysfunction (OR 18.7) and dysautonomia (OR 11.6) were the strongest predictors.⁶
Evidence base — respiratory complications in neuromuscular series run 0–54%; sugammadex looks safe but data are thin.²

Follow-up question

The next morning you are called to the ward for a 38-year-old woman admitted three days ago with ascending weakness from Guillain-Barré syndrome. Her vital capacity is now 15 mL/kg, she cannot count to 15 in one breath, and her blood pressure has swung from 190/100 to 85/45 in an hour with heart rate 50 to 130. What do you do?

Follow-up answer

HeadlineImpending respiratory failure with dysautonomia; I move her to the ICU and intubate now, before she tires.

Her vital capacity is below the 20 mL/kg threshold,³ and dysautonomia predicts ventilation.⁶ I place an arterial line first, then induce with small doses of a short-acting agent and rocuronium, never succinylcholine.³ Atropine, phenylephrine and a vasodilator are drawn up, because her swings can be extreme either way. Neurology starts IVIG or plasma exchange. I reassess hemodynamics continuously and plan early tracheostomy if weakness persists.

Pitfalls that cost points

Trusting quantitative train-of-four in a Guillain-Barré survivor: persistent neuropathy can make it unreliable.³
Reading a normal SpO2 as adequate ventilation in neuromuscular weakness: hypercapnia comes first, and oxygen hides it.

Rapid-fire

Q: How long do patients with ALS survive? A: Mean 2–4 years from onset, about 1.5 years with early bulbar symptoms; bulbar palsy is present at onset in about 25%.¹

Q: What is the classic ALS teaching on neuraxial technique? A: Exacerbations after neuraxial blocks have been reported but are contested; epidural is generally favored over intrathecal.¹

Q: What predicts relapse after delivery in MS? A: Disease activity during pregnancy or the year before conception, not the neuraxial technique.⁵

Q: How often does Guillain-Barré need mechanical ventilation? A: Up to a third in general series; 17% in a 2024 cohort.⁶

Q: Is sugammadex safe in neuromuscular disease? A: Most reviews consider it safe, but the evidence is limited.²

Numbers to know

Item	Value
GBS intubation: vital capacity	<20 mL/kg³
GBS: MIP / MEP	Weaker than 30 / under 40 cmH2O³
GBS dysautonomia	36% of patients⁶
GBS ventilated	17% (up to one third)⁶
MS neuraxial reports reviewed	37 reports, 231 patients⁴
Bulbar onset in ALS	~25%¹

Sources

1.ALS: anesthetic concerns · OpenAnesthesia · openanesthesia.org
2.Mapping the current evidence on the anesthetic management of adult patients with neuromuscular disorders: a scoping review · Canadian Journal of Anesthesia, 2022 · link.springer.comvan den Bersselaar LR, et al. Can J Anesth 2022;69:756-73.
3.Guillain-Barré syndrome · NYSORA · nysora.comVentilation thresholds and succinylcholine only; its IVIG dose (mg/kg) is a units error and is not used here.
4.Neuraxial anesthesia in patients with multiple sclerosis: a systematic review · Brazilian Journal of Anesthesiology, 2017 · bjan-sba.orgBornemann-Cimenti H, et al. Braz J Anesthesiol 2017;67:404-10. 37 reports, 231 patients.
5.Multiple sclerosis · NYSORA · nysora.comCites a 2025 systematic review: 8 studies, 1,315 parturients, no increase in postpartum relapse with neuraxial.
6.Clinical predictors for mechanical ventilation assistance in Guillain-Barré syndrome · Frontiers in Neurology, 2024 · frontiersin.orgRodríguez-Méndez AA, et al. Front Neurol 2024;15:1385945. 222 patients.

Facts on this page were checked against these sources on Oct 22, 2026. Guidelines change; confirm doses against current institutional protocols.