Guillain–barré Syndrome

Basics

Description

Group of peripheral nerve disorders characterized by autoimmune demyelination and axonal degeneration of peripheral nerves usually leading to acute ascending paralysis
Humoral and cellular immune mediated
Leading cause of acute flaccid paralysis worldwide (since polio vaccination)
Triggered by antecedent bacterial/viral infection
Increasing incidence with advancing age, male gender
- Average 1.1 per 100,000 per yr
Weakness reaches nadir at 2–4 wk
Spontaneous resolution occurs over weeks to months:
- 80% full recovery at 1 yr
- 20% unable to walk at 6 mo
- 5% die of complications:
  - PE
  - Infection
  - Cardiac
Acute inflammatory demyelinating polyradiculoneuropathy (AIDP):
- Most common form of Guillain–Barré syndrome (GBS; 90% of all GBS cases)
- Demyelination sometimes accompanied by axonal loss
Other forms of GBS:
- Acute motor axonal neuropathy (AMAN):
  - Pure motor axonal involvement
  - 67% seropositive for Campylobacter jejuni
  - Recovery often rapid
  - Often pediatric patients
- Acute motor sensory axonal neuropathy (AMSAN):
  - Degeneration of myelinated motor and sensory nerves without significant inflammation or demyelination
  - Similar to AMAN, but also involves sensory nerves
- Acute panautonomic neuropathy:
  - Very rare
  - Involves sympathetic and parasympathetic nerves
  - Postural hypotension, dysrhythmias, tachycardia, hypertension
  - Blurry vision, dry eyes, anhidrosis
  - Recovery gradual, often incomplete
- Miller Fisher syndrome:
  - Rare
  - Rapidly evolving ataxia, areflexia, and ophthalmoplegia without weakness
  - Demyelination and inflammation of cranial nerves II and VI, spinal ganglia, and peripheral nerves
  - Resolves in 1–3 mo

Etiology

Postinfectious:
- 2/3 with antecedent illness, usually respiratory or GI
- Different autoantibodies associated with different subtypes
- 1–3 wk between prodromal illness and neurologic symptoms
- C. jejuni most common antecedent bacterial infection
- Cytomegalovirus most common antecedent viral infection
- Epstein–Barr virus, VZV, HIV, mycoplasma also associated
- Emerging association with Zika virus, unclear if other viruses also necessary to precipitate GBS after Zika
- Also emerging association with immune modulators (e.g., adalimumab)
- Relationship to vaccines is questionable
- Slightly increased risk ascribed to influenza vaccine
  - Incidence ∼2 cases per million vaccines given
  - Lower than risks associated with developing influenza
- Case reports of GBS after meningococcal vaccine in adolescent
  - No definite association in larger studies

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