Guillain-Barré Syndrome

Guillain-Barré Syndrome is a topic covered in the 5-Minute Clinical Consult.

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  • A group of acquired autoimmune disorders causing acute peripheral neuropathy and ascending paralysis that progressively worsens for up to 4 weeks followed by a slow spontaneous recovery of function
  • Subtypes classified by pattern of neural injury:
    • Acute inflammatory demyelinating polyradiculoneuropathy (AIDP): progressive limb weakness with areflexia (~95% of GBS cases in Europe and North America)
    • Axonal subtypes:
      • Acute motor axonal neuropathy (AMAN): pure motor neuropathy strongly associated with Campylobacter jejuni and a higher rate of respiratory failure (~5% of cases in Europe and North America but 30–47% of cases in China, Japan, and Central and South America)
      • Acute motor-sensory axonal neuropathy (AMSAN): combined motor–sensory neuropathy; poor prognosis with prolonged course
    • Regional subtypes:
      • Miller Fisher syndrome (MFS): triad with ophthalmoplegia, ataxia, and areflexia; antibodies to GQ1b present in 90% of patients with MFS
      • Bickerstaff encephalitis: possible variant of MFS with encephalopathy, ophthalmoplegia, ataxia, and hyperreflexia
      • Pharyngeal-cervical-brachial GBS: Parasympathetic and cholinergic dysfunction leads to neck, arm, and oropharyngeal weakness along with upper extremity areflexia.
    • Sensory subtypes:
      • Acute pandysautonomia: orthostatic hypotension, gastroparesis, ileus, constipation/diarrhea, sudomotor/pupillary abnormalities, and neuropathic pain
      • Acute sensory ataxic neuropathy (ASAN): controversial variant with sensory loss and ataxia
  • Polyneuritis cranialis: bilateral cranial nerve involvement and severe peripheral sensory loss associated with cytomegalovirus (CMV) infections
  • Synonym(s): GBS, AIDP; Landry-Guillain-Barré-Strohl syndrome, acute inflammatory idiopathic polyneuritis; acute autoimmune neuropathy; Landry ascending paralysis

Rapidly progressing paralysis and respiratory failure occur in 20–30% of patients. Some require mechanical ventilation within 48 hours.

Areflexia is a red flag for GBS in patients with rapidly progressive limb weakness.

A history of weakness preceded by respiratory or GI infection suggests GBS.


  • Most common acute paralytic disease in Western countries
  • 0.6 to 2.0/100,000 worldwide
  • U.S. incidence: 0.9 to 1.8/100,000
  • Increases with age: 0.8/100,000 in children <18 years of age; 3/100,000 in adults >60 years
  • 1.5 times higher incidence in males

Etiology and Pathophysiology

  • Autoimmune process targets Schwann cell surface membrane, myelin, and/or gangliosides causing peripheral nerve destruction and demyelination.
  • Pathogenesis thought to involve molecular mimicry (i.e., an immune response to antigenic targets that are coincidentally shared by infectious organisms and host peripheral nerve tissue)

Host factors appear to play a role in GBS, but no clear genetic risk has been identified.

Risk Factors

Influenza vaccinations

  • Inactivated seasonal flu vaccines associated with an increase in GBS risk equivalent to one case/million vaccines above background incidence (far less than the 17 cases of GBS per million people infected with influenza virus)
  • Incidence of GBS associated with influenza vaccine has steadily decreased over time.
  • Of historical note: Increased incidence during 1976 U.S. National H1N1 Immunization Program had vaccine-attributable risk of 8.8 per million recipients compared to 1.6 per million recipients in the 2009 H1N1 vaccination campaign.

Commonly Associated Conditions

Infection of the respiratory (22–53%) or GI tract (6–26%) in preceding 6 weeks

  • C. jejuni: most common precipitant of GBS, (21–40% of cases):
    • Associated with axonal degeneration, slower recovery, more severe residual disability
  • CMV: Primary CMV infection precedes 10–22% of cases.
  • Rarely associated with Mycoplasma pneumoniae, influenza infection, Epstein-Barr virus, varicella-zoster virus, HIV infection, and some arboviral infections

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