Neurology for MRCPI Part 1

A 29-year-old woman presents with 5 days of progressive symmetrical weakness starting in her legs and ascending, now affecting her arms. Reflexes are absent throughout. She had gastroenteritis three weeks ago. Forced vital capacity is 1.8 L and falling. What is the most important immediate management priority?

1. Immediate high-dose corticosteroids Wrong. Steroids are ineffective in GBS and are not recommended, unlike in chronic inflammatory demyelinating polyneuropathy.
2. Urgent MRI of the whole spine as the priority Useful to exclude a compressive lesion where the presentation is atypical, but it does not take priority over airway and respiratory monitoring in a patient with a falling vital capacity.
3. Serial monitoring of forced vital capacity with early critical care involvement correct Correct. In Guillain–Barré syndrome the thing that kills is neuromuscular respiratory failure, and it can develop with normal oxygen saturations right up until decompensation. Serial FVC, not saturations, not blood gases, is the monitoring that matters, and a falling FVC around 1 L or 15 to 20 mL/kg warrants intubation.
4. Pulse oximetry alone, escalating if saturations fall below 92% Wrong and a classic trap. Oxygen saturation is preserved until very late in neuromuscular respiratory failure. Waiting for desaturation means intubating a patient in extremis.
5. Start intravenous immunoglobulin and discharge home to complete the course Wrong. IVIg or plasma exchange is indeed the disease-modifying treatment, but discharging a patient with a falling FVC and autonomic instability risk would be dangerous.

The point: GBS: ascending weakness, areflexia, albuminocytological dissociation in CSF, often post-Campylobacter. Treat with IVIg or plasma exchange, never steroids. Monitor FVC serially, watch for autonomic instability, and give thromboprophylaxis.

Source: Association of British Neurologists — Guillain–Barré syndrome management guideline Association of British Neurologists · tier 2, specialty society or college