Emergency Briefcase

Guillain–Barré Syndrome

Recognize progressive weakness, anticipate respiratory and autonomic deterioration, and initiate evidence-based therapy without waiting for every confirmatory test.

Neurologic emergency: a patient who is speaking normally and maintaining oxygen saturation may still have rapidly declining neuromuscular respiratory reserve.
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The Case Begins

Progressive weakness after gastroenteritis

A 43-year-old man reports tingling in both feet followed by progressive leg weakness over three days. Today he needs help standing. He had diarrhea two weeks ago. HR 104, BP 148/86, RR 20, SpO₂ 98% on room air. Strength is 3/5 in both legs and 4/5 in both arms; patellar and Achilles reflexes are absent.

Immediate priorities

  • Trend respiratory mechanics
  • Assess bulbar function and cough
  • Cardiac and blood-pressure monitoring
  • Neurology involvement and monitored admission
  • Evaluate important mimics

Decision 1

What is the most important next action?

Best answer: B. Normal pulse oximetry does not measure neuromuscular reserve. Progressive weakness requires serial FVC and inspiratory/expiratory pressure assessment plus close airway, bulbar, and autonomic monitoring.
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Recognize the Syndrome

BilateralProgressive limb weakness
Reflexes ↓Absent or decreased
≤4 weeksTime to clinical nadir
PostinfectiousOften follows GI or respiratory illness

Supportive features

  • Relatively symmetric weakness
  • Distal paresthesias or neuropathic pain
  • Facial or bulbar weakness
  • Autonomic dysfunction
  • Back or radicular pain
  • Progression over hours to days

Variants

  • Acute inflammatory demyelinating polyneuropathy
  • Acute motor axonal neuropathy
  • Acute motor-sensory axonal neuropathy
  • Miller Fisher syndrome
  • Pharyngeal-cervical-brachial variant

Features that demand an alternative diagnosis

A clear sensory level, marked persistent asymmetry, early bowel/bladder dysfunction, hyperreflexia with an upper-motor-neuron pattern, altered consciousness, or a high CSF pleocytosis should prompt an expanded differential.

Decision 2

Which finding is most characteristic of typical GBS?

Best answer: C. Progressive bilateral weakness and reduced reflexes are core clinical features. The other options suggest central myelopathy or neuromuscular-junction disease.
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Respiratory and Bulbar Risk

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Declining FVC
Especially FVC <20 mL/kg or a substantial serial decline
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Bulbar weakness
Dysphagia, weak voice, secretion difficulty, weak cough
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Rapid progression
Weakness evolving over hours to a few days
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Autonomic instability
Marked BP/HR fluctuation or dysrhythmia

Respiratory checkpoint

Enter the current values and interpret them with the trend, cough, bulbar function, and clinical trajectory.

Do not wait for late signs

Hypoxemia and hypercapnia are late manifestations of neuromuscular respiratory failure. If airway protection or ventilation is becoming unreliable, controlled early intubation is safer than a crash airway.

Decision 3

FVC falls from 26 to 18 mL/kg, cough is weak, and speech becomes soft. SpO₂ remains 98%. What is the best next step?

Best answer: D. Declining mechanics plus a weak cough and bulbar change signal impending failure despite normal oxygen saturation.
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Diagnostic Workup

CSF

Albuminocytologic dissociation—elevated protein with a low white-cell count—supports GBS. Protein may still be normal during the first week. A marked pleocytosis should trigger evaluation for an alternative process.

Nerve conduction studies / EMG

Electrodiagnostic testing can support the diagnosis and classify subtype, but early studies may be nondiagnostic. Repeat testing may be needed.

Targeted tests

  • Electrolytes including potassium, magnesium, and phosphate
  • ECG and continuous telemetry
  • Spinal MRI when cord or cauda equina pathology is plausible
  • Infectious, toxic, nutritional, or antibody testing when clinically indicated

Important mimics

  • Acute myelopathy or spinal cord compression
  • Myasthenia gravis or botulism
  • Tick paralysis
  • Hypokalemic paralysis
  • Porphyria, diphtheria, or toxic neuropathy
  • Critical illness neuropathy

Decision 4

LP on illness day 3 shows normal CSF protein and 3 WBC/µL. How should this affect your assessment?

Best answer: A. CSF protein can be normal early. Diagnosis and monitoring remain anchored in the clinical trajectory.
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Disease-Modifying Treatment

TherapyRoleKey point
IV immunoglobulin0.4 g/kg/day for 5 days is a standard regimen.Recommended for patients unable to walk unaided; consider in ambulatory patients with rapid progression or severe bulbar, respiratory, or autonomic involvement.
Plasma exchangeEffective alternative first-line therapy.Choice depends on contraindications, access, hemodynamics, and local expertise.
CorticosteroidsNot effective as GBS monotherapy.Do not use routine steroids to treat GBS.
Sequential PE + IVIGNot routine.Combination does not provide established added benefit.

Supportive care is active treatment

  • DVT prophylaxis
  • Pressure-injury prevention and positioning
  • Pain management
  • Swallow assessment and nutrition
  • Physical and occupational therapy
  • Bladder, bowel, and infection surveillance

Decision 5

The patient can no longer walk independently. Which disease-modifying strategy is appropriate?

Best answer: B. IVIG and plasma exchange are effective first-line options. Treatment should not be delayed for electrodiagnostic subtype confirmation when the clinical diagnosis and severity justify therapy.
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Monitoring and Disposition

Trend respiratory functionSerial FVC and inspiratory/expiratory pressures; assess cough, secretion handling, voice, and swallowing.
Watch autonomic functionContinuous rhythm monitoring and frequent blood-pressure assessment; avoid reflexively treating transient swings.
Track neurologic progressionDocument strength, cranial nerves, reflexes, gait, and tempo. Rapid change should prompt ICU escalation.
Plan beyond the EDNeurology consultation, monitored admission, rehabilitation planning, and prevention of immobility complications.

Common mistakes

  • Using SpO₂ as a respiratory-strength test
  • Relying on one FVC rather than the trend
  • Excluding GBS because early CSF or EMG is normal
  • Missing autonomic instability
  • Using corticosteroids as definitive therapy

Escalate care for

  • Rapidly progressive weakness
  • Bulbar or facial weakness
  • Weak cough or secretion retention
  • Declining respiratory mechanics
  • Marked dysautonomia or dysrhythmia
  • Inability to lift the head or stand
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Case Recap

0/5Complete the five decisions to generate your result.

Critical actions

  1. Recognize progressive bilateral weakness with reduced reflexes.
  2. Measure and trend respiratory mechanics early.
  3. Assess bulbar function and autonomic instability.
  4. Do not let normal early CSF, EMG, or SpO₂ create false reassurance.
  5. Use IVIG or plasma exchange when treatment is indicated.
  6. Provide monitored supportive care and anticipate deterioration.
Emergency Briefcase · Guillain–Barré Syndrome Interactive Learning Module