Can you provide typical viva (oral exam) questions for Guillain‑Barré syndrome?

Guillain-Barré Syndrome (GBS) Viva Questions

Based on the 2019 Nature Reviews Neurology international consensus guideline 1, here are comprehensive viva questions organized by clinical domains:

Clinical Presentation & Diagnosis

1. What are the cardinal diagnostic features of classic GBS?

• Rapidly progressive bilateral weakness of legs and/or arms without CNS involvement 1
• Distal paraesthesias or sensory loss followed by ascending weakness (legs → arms → cranial muscles) 1
• Decreased or absent reflexes at presentation, universally absent at nadir 1
• Maximum disability reached within 2 weeks in most patients 1
• Critical pitfall: If maximum disability occurs within 24 hours or after 4 weeks, consider alternative diagnoses 1

2. Describe the typical CSF findings in GBS and their timing.

• Classic albuminocytologic dissociation: elevated protein with normal cell count 1
• Important caveat: CSF can be completely normal early in disease course 1
• CSF examination is most valuable when diagnosis is uncertain 2

3. What are the electrophysiological subtypes of GBS?

• AIDP (Acute Inflammatory Demyelinating Polyradiculoneuropathy) 1
• AMAN (Acute Motor Axonal Neuropathy) 1
• AMSAN (Acute Motor Sensory Axonal Neuropathy) 1
• Key point: The demyelinating vs. axonal dichotomy is increasingly challenged and does not guide treatment selection 3

4. What atypical presentations of GBS occur in young children (<6 years)?

• Poorly localized pain 1
• Refusal to bear weight 1
• Irritability and meningism 1
• Unsteady gait 1
• Clinical trap: These nonspecific features frequently cause diagnostic delay 1

Clinical Variants

5. Name the recognized clinical variants of GBS.

• Pure motor variant (weakness without sensory signs) 1
• Miller Fisher Syndrome (ophthalmoplegia, areflexia, ataxia) 1
• Pharyngeal-cervical-brachial weakness 1
• Paraparetic variant (lower limb predominant) 1
• Bilateral facial palsy with paraesthesias 1

6. What is Miller Fisher Syndrome and how is it diagnosed?

• Classic triad: ophthalmoplegia, areflexia, and ataxia 1
• Associated with anti-GQ1b IgG antibodies 1
• Often overlaps with other GBS variants 1
• Testing recommendation: Anti-GQ1b antibody testing should be performed when MFS is suspected 2

7. When should you consider changing the diagnosis from GBS to A-CIDP?

• If progression continues beyond 8 weeks from onset 2
• Occurs in approximately 5% of patients initially diagnosed with GBS 2

Autonomic Dysfunction & Complications

8. What autonomic manifestations occur in GBS?

• Blood pressure instability 1
• Heart rate variability and cardiac arrhythmias 1
• Pupillary dysfunction 1
• Bowel and bladder dysfunction 1
• Mortality impact: Autonomic dysfunction contributes significantly to the 3-10% mortality rate 1

9. What percentage of GBS patients require mechanical ventilation?

• Approximately 20% develop respiratory failure requiring mechanical ventilation 1
• Critical monitoring point: Respiratory failure can occur without dyspnea symptoms 1
• Respiratory function must be monitored in all patients 1

10. What is the mEGRIS score and when should it be used?

• Modified Erasmus GBS Respiratory Insufficiency Score 2
• Used to assess risk of requiring artificial ventilation 2
• Should be calculated on admission 4

Treatment

11. What are the two proven effective treatments for GBS?

• Intravenous immunoglobulin (IVIg): 0.4 g/kg daily for 5 days 1
• Plasma exchange (PE): 200-250 ml/kg over 4-5 sessions 1
• Both are equally effective 1
• Evidence level: These remain the only proven treatments after 30 years 5

12. When should treatment be initiated in GBS?

• IVIg recommended within 2 weeks of weakness onset if unable to walk unaided 2
• PE recommended within 4 weeks of weakness onset if unable to walk unaided 2
• Practice point: Treatment is frequently given even in mild cases (75% of ambulatory patients) despite lack of trial evidence 6

13. Should corticosteroids be used in GBS?

• Recommend against oral corticosteroids 2
• Weakly recommend against IV corticosteroids 2
• No proven benefit in GBS 1

14. What is the approach to treatment failure in GBS?

• Occurs in approximately 32% of patients 6
• Only 35% of treatment failures receive second immunotherapy 6
• Evidence gap: Efficacy of repeat treatment is uncertain 1
• Current practice: Second course is common despite lack of evidence 1

15. Should PE followed immediately by IVIg be used?

• Not recommended 2
• No additional benefit demonstrated 2

Prognosis & Recovery

16. What is the mEGOS score and its clinical utility?

• Modified Erasmus GBS Outcome Score 1
• Should be calculated on admission to predict outcome 1
• Moderately reliable predictor of independent ambulation at 3 months and beyond 4

17. What is the typical recovery timeline in GBS?

• 60-80% walk independently at 6 months 1
• Most extensive improvement occurs in first year 1
• Recovery can continue for >3 years (some sources state >5 years) 1
• Long-term perspective: Clinical improvement may continue beyond 5 years 1

18. What is the recurrence rate of GBS?

• Rare: 2-5% of patients 1
• GBS is fundamentally a monophasic illness 1

19. What are treatment-related fluctuations (TRFs)?

• Deterioration after initial stabilization or improvement on therapy 1
• Occurs in approximately 5% of patients 1
• 68% are re-treated with IVIg or PE 6
• Evidence limitation: No trial data supports re-treatment, but commonly practiced 6

Epidemiology & Etiology

20. What is the global incidence of GBS?

• Approximately 1-2 per 100,000 person-years 1
• More frequent in males than females 1
• Incidence increases with age, though all ages can be affected 1

21. What proportion of GBS patients report preceding infection?

• About two-thirds report infection symptoms in the 6 weeks preceding onset 1
• Recent association: Zika virus epidemics linked to increased GBS incidence 1
• Six pathogens have been temporally associated with GBS 1

Pain Management

22. What pharmacological options exist for pain management in GBS?

• Weakly recommend: Gabapentinoids, tricyclic antidepressants, or carbamazepine 2
• Pain is frequently reported and can be muscular, radicular, or neuropathic 1
• Evidence gap: No specific treatment recommended for fatigue 2

Diagnostic Pitfalls

23. What reflexes might be preserved in atypical GBS?

• Pure motor variant with AMAN subtype may show normal or exaggerated reflexes throughout disease course 1
• Classic teaching challenged: Areflexia is not universal in all GBS presentations 1

24. When is anti-ganglioside antibody testing clinically useful?

• Limited value in typical motor-sensory GBS 2
• Anti-GQ1b testing indicated when Miller Fisher syndrome suspected 2
• Nodal-paranodal antibodies should be tested when autoimmune nodopathy suspected 2

25. When should advanced imaging (MRI/ultrasound) be considered?

• In atypical cases where diagnosis is uncertain 2
• Not routinely required for typical GBS presentations 2