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This is a clinician-written, evidence-based summary aligned to the USMLE Step 2 CK Content Outline. It is intended for medical students preparing for USMLE Step 2 CK. Management reflects current ACC/AHA, USPSTF, and APA guidelines. Always cross-reference with UpToDate, institutional protocols, and clinical judgment.
The Bottom Line
- Ascending weakness with areflexia after infection
- CSF shows albuminocytologic dissociation
- Monitor FVC and NIF for respiratory failure
- Treat significant/progressive disease with IVIG or plasma exchange
- Steroids are not effective
Overview
GBS is an acute immune-mediated peripheral nerve/root disorder, commonly AIDP in the US. It often follows infection and may cause respiratory failure or autonomic instability.
Epidemiology
Triggers include Campylobacter, CMV, EBV, influenza, HIV, Zika, surgery, and rarely vaccination.
Clinical Features
Symptoms
Ascending symmetric weakness
Paresthesias or radicular pain
Facial weakness or dysphagia
Dyspnea or weak cough
Autonomic symptoms
Signs
Areflexia or hyporeflexia
Flaccid weakness
Bilateral facial weakness
Mild sensory findings relative to weakness
Labile BP or arrhythmias
Investigations
First-line
FVC/NIFSerial respiratory monitoring
LPHigh protein with normal WBC; may be normal early
BMP/CBC/CKExclude mimics and monitor complications
Second-line
EMG/NCSDemyelinating or axonal pattern
MRI spineExclude cord lesion; may show root enhancement
Anti-GQ1bMiller Fisher support
Specialist
TelemetryAutonomic instability
Swallow assessmentBulbar weakness
1
Supportive
- Admit progressive cases
- Serial FVC/NIF
- DVT prophylaxis and pain control
- Avoid succinylcholine
2
Immunotherapy
- IVIG or plasma exchange
- Do not combine routinely
- Start early in nonambulatory/progressive disease
- Steroids not effective
3
Respiratory
- ICU for bulbar/autonomic/respiratory signs
- Intubate for declining FVC/NIF or weak cough
- Continuous telemetry
- Treat autonomic swings cautiously
4
Recovery
- Rehabilitation
- Monitor residual pain/fatigue
- Progression >8 weeks suggests CIDP
- Educate on prolonged recovery
Complications
- Respiratory failure: Most dangerous complication
- Autonomic instability: Arrhythmias and BP swings
- DVT/PE: Immobility
- Residual weakness: Recovery may be prolonged
USMLE Step 2 CK Exam Tips
- 1Ascending weakness + areflexia = GBS
- 2Albuminocytologic dissociation = high protein normal WBC
- 3Normal early CSF does not exclude GBS
- 4Most important monitoring = FVC/NIF
- 5Treatment = IVIG or plasma exchange
- 6Steroids are not effective
- 7Ophthalmoplegia + ataxia + areflexia = Miller Fisher
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