Guillain-Barre Syndrome (GBS)

Definition

GBS refers to a group of acquired, immune-mediated, inflammatory polyradiculoneuropathies sharing an acute onset, elevated CSF protein with low cell counts (cytoalbuminologic dissociation), and a monophasic course. - Goldman-Cecil Medicine, p. 2387

Epidemiology

Annual incidence: 1-2 per 100,000
Men > Women (1.4:1 ratio)
60% of patients have a preceding respiratory tract infection or gastroenteritis
AIDP accounts for ~97% of cases in North America and Europe
Key infectious triggers: Campylobacter jejuni (especially axonal variants), EBV, CMV, hepatitis E (5-10% in Belgium/Netherlands), Zika virus
GBS was not substantially increased by SARS-CoV-2 infection or most COVID vaccines (minor exception: ChADOx1nCoV-19 vaccine, +0.6 cases/100,000 doses); GBS incidence actually declined during the pandemic
Goldman-Cecil Medicine, p. 2392

Subtypes / Classification

Subtype	Key Features
AIDP (Acute Inflammatory Demyelinating Polyradiculoneuropathy)	Most common in USA/Europe; demyelinating; multifocal inflammation of spinal roots and peripheral nerves
AMAN (Acute Motor Axonal Neuropathy)	Pure motor axonal injury; first described in northern China; summer epidemics; C. jejuni associated
AMSAN (Acute Motor-Sensory Axonal Neuropathy)	Both motor and sensory axons; more severe; poor recovery
Miller-Fisher Syndrome (MFS)	Triad: ophthalmoplegia, ataxia, areflexia; anti-GQ1b antibodies (>85%); 6% of Western GBS, 18% in Taiwan

Bradley and Daroff's Neurology, p. 2663

Pathobiology

All forms likely result from post-infectious molecular mimicry - the immune system attacks peripheral nerve antigens that resemble microbial antigens (particularly C. jejuni). The HS:019 serotype of C. jejuni is common in AMAN patients in northern China. However, molecular mimicry for AIDP is less clearly established. - Goldman-Cecil Medicine, p. 2397

Clinical Features

Core presentations:

Weakness is the most common initial symptom - ranges from difficulty walking to total quadriplegia and respiratory failure
Typically starts in the legs and ascends to the arms (ascending paralysis)
Bilateral facial weakness in 50% of patients
Proximal weakness is common; 5% have isolated cranial nerve involvement descending to limbs
Slight sensory loss in most patients
Autonomic nervous system involvement in ~65% of cases

Progression:

Weakness progresses over days to 4 weeks
Nadir typically at 2-4 weeks
Recovery begins 2-4 weeks after progression stops

Red flags suggesting alternative diagnosis:

Asymmetric weakness
CNS abnormalities
Bowel/bladder dysfunction early
Sensory level (suggests myelopathy)
Goldman-Cecil Medicine, p. 2402

Diagnosis

Required Criteria (Box 106.10)

Progressive weakness of both legs and arms
Areflexia or hyporeflexia

Supportive Clinical Features

Progression over days to 4 weeks
Relative symmetry
Mild sensory symptoms
Bifacial palsies
Autonomic dysfunction
Absence of fever at onset
Recovery beginning 2-4 weeks after progression

Laboratory / Ancillary Studies

CSF findings:

Elevated protein with <10 cells/μL (albuminocytological dissociation)
CSF protein may be normal in up to 50% in the first week; remains normal throughout in ~10%
CSF WBCs >50/mL suggests HIV seroconversion or Lyme disease
Transient oligoclonal IgG bands and elevated myelin basic protein may occur

Electrodiagnostic studies (EDX):

Abnormalities found in ~90% of established cases
Key early findings: absent H reflexes, absent/delayed/impersistent F waves
Sural sparing pattern (reduced upper extremity SNAPs + normal sural SNAP) - ~50% in first 2 weeks; 96% specific for AIDP when combined with abnormal F waves
Reduced motor conduction velocity, prolonged distal latencies, conduction block
Bradley and Daroff's Neurology, pp. 2183-2195

Differential Diagnosis

Condition	Distinguishing Feature
Botulism	Ophthalmoplegia, unreactive pupils, dry mouth, no sensory symptoms
Myasthenia gravis	Ptosis, diplopia, dysphagia - NMJ disorder
Acute myelopathy (transverse myelitis)	Brisk reflexes, sensory level, bowel/bladder dysfunction
Tick paralysis	Resolves with tick removal
AION/AMSAN	Axonal on NCS, more severe
Polio-like viral syndromes	West Nile, ECHO 70, coxsackievirus - asymmetric

Treatment

Supportive care:

Monitor respiratory function (serial FVC measurements) - intubation if FVC <15-20 mL/kg or if bulbar function compromised
ICU monitoring for autonomic instability
DVT prophylaxis
Pain management
Nutritional support

Disease-modifying therapy (two equally effective options):

Intravenous immunoglobulin (IVIG) - 2 g/kg over 2-5 days
- Preferred when venous access is difficult, hemodynamic instability, or active infection
Plasma exchange (plasmapheresis) - typically 5 exchanges over 1-2 weeks
- Removes circulating antibodies and complement

Important notes:

Corticosteroids are NOT effective and do not improve outcome in GBS
Combining IVIG and plasma exchange offers no advantage over either alone
Early treatment is important - most benefit within 2 weeks of symptom onset
Severity scoring (EGOS/mEGOS scores) helps predict outcome and need for mechanical ventilation

Prognosis:

Mortality has fallen from ~33% (pre-ventilator era) to 1-5% with modern ICU care
~80% of patients eventually walk independently
~10% have severe permanent disability
Poor prognostic factors: older age, rapid onset, preceding C. jejuni infection, axonal variant, prolonged ventilation
Bradley and Daroff's Neurology; Goldman-Cecil Medicine

Recent Evidence (2024-2026)

A 2026 systematic review (PMID: 41038424) confirmed that structured physical exercise programs significantly improve fatigue and functional capacity in patients with GBS and CIDP, supporting early rehabilitation as part of comprehensive management. No recent meta-analyses challenge the established IVIG/plasma exchange treatment paradigm.

This is a shared conversation. Sign in to Orris to start your own chat.