Guillain-Barre Syndrome — Written Clinical Reasoning

SAQ 1 — Severe Guillain-Barré syndrome at the respiratory-failure threshold (20 marks, 30 minutes)

Prompt: Outline your assessment and management, covering confirmation of the diagnosis, airway and respiratory decisions, disease-modifying therapy with dose and evidence, supportive care, and prognosis.^[1]

Case vignette: A 54-year-old man, two weeks after Campylobacter jejuni enteritis, has progressive symmetric ascending weakness with areflexia and cannot walk. Vital capacity is 19 mL/kg and falling, MIP 28 cmH2O, MEP 38 cmH2O, weak cough, bilateral facial weakness. CSF protein is raised with 3 cells/μL.^[1]

Model answer

Diagnosis (3 marks). Clinical GBS, supported by CSF albumino-cytological dissociation; Campylobacter jejuni is one of six pathogens temporally associated with GBS. CSF protein is normal in 30-50% in week 1, and over 50 cells/μL would suggest another diagnosis. In the Brighton series electrophysiology was compatible with neuropathy in 99%.^[1][4]

Airway and respiratory (5 marks). He meets the 20/30/40 rule (VC under 20 mL/kg, MIP under 30, MEP under 40 cmH2O). Bilateral facial weakness, bulbar dysfunction, rapid progression and dysautonomia make ventilation highly likely, and no clinical feature predicts the pattern of decline — admit to ICU and intubate electively. Avoid suxamethonium (hyperkalaemic arrhythmia reported) and do not bridge with BiPAP (both reported patients needed emergency intubation).^[1][3][9][8]

Disease-modifying therapy (6 marks). EAN/PNS 2023: IVIg 0.4 g/kg/day for 5 days within 2 weeks (strong) or plasma exchange 12-15 L in four to five exchanges over 1-2 weeks within 4 weeks (strong); no preference. The 1997 international trial (383 patients) found PE, IVIg and PE-then-IVIg equivalent (0.9, 0.8, 1.1 grades). No corticosteroids: methylprednisolone with IVIg gave 68 vs 56% improvement (P = 0.06), Cochrane found no benefit, and EAN/PNS recommends against oral (strong) and IV (weak) steroids. No second IVIg course.^{[2][5][11][6]}

Supportive care (4 marks). Monitor for arrhythmias and blood-pressure instability, which contribute to a 3-10% mortality; prevent pressure ulcers, hospital-acquired infections and DVT; protect the airway with bulbar palsy and the cornea with facial palsy; treat pain with gabapentinoids or tricyclics before carbamazepine. Plan for prolonged ventilation: only 22% of ventilated patients weaned within 3 weeks and 87% had a tracheostomy.^[1][2][10]

Prognosis (2 marks). About 80% walk independently at 6 months; mEGOS (age, preceding diarrhoea, MRC sum score) estimates his chance.^[1]