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GBS Respiratory Failure — RACP Adult Medicine MCQ

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HardEmergency MedicineGBS Respiratory FailureRACP Adult Medicine

A 30-year-old man presents with a 2-week history of progressive bilateral ascending weakness starting in his feet. He is now unable to walk. FVC is 1.2 L (predicted 4.5 L). Nerve conduction studies show demyelination. CSF protein is elevated at 1.8 g/L with normal cell count. What is the most critical management priority?

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Correct answer: C — Intubation and mechanical ventilation

With an FVC of 1.2 L (27% predicted – critically low), immediate intubation and mechanical ventilation is the priority, as respiratory failure is the leading cause of death in GBS. The '20-30-40 rule' guides intubation: FVC <20 mL/kg, MIP >-30 cmH₂O, or MEP <40 cmH₂O. IVIg or plasma exchange should be commenced concurrently but airway protection takes precedence. FVC should be monitored 4–6 hourly in the acute phase.

Reference: eTG – 2025 – Neurology; EAN/PNS – 2023 – GBS Guidelines