Guillain-Barre Syndrome
Last Updated : 4/3/2007
Shawn Aylward
Although GBS can be diagnosed on clinical exam and testing is not specifically needed, most practitioners obtain a lumbar puncture for confirmation (see table 1).(12) The characteristic cerebrospinal fluid (CSF) finding is albuminocytologic dissociation. This means there is disproportionate elevation in CSF protein with absence of inflammation (i.e. white blood cells). Caution should be exercised if performed in the first week of symptoms as CSF can still be normal. Evidence of CSF pleocytosis should direct the clinician away from the diagnosis of GBS.
Electromyography (EMG) demonstrates multifocal slowing of nerve conduction velocities or conduction block. For typical AIDP cases, EMG shows asymmetric slowing of nerve conduction velocities in peripheral nerves, unequal conduction velocities in comparable nerve segments or conduction block. Prolongation or loss of the F-wave is an initial finding and can be seen before the CSF abnormalities. Later, H-waves can have similar findings, both of which indicate injury to the proximal nerve or spinal root. EMG can help assist in prognosis in terms of confirming axonal injury which would result in a longer time to reach final recovery.
Postcontrast MRI images can show enhancement of the cauda equine, lumbar nerves and nerve roots.
On pathologic exam, AIDP cases show segmental demyelination, often resulting in mild secondary axonal degeneration. Antibodies bind to the outer surface of the Schwann cell and through complement activation initiates myelin vesiculation. In AMAN, macrophages bind directly to axolemma at the nodes of Ranvier. The pathology seen with AMSAN resembles that in AMAN, with the exception that the dorsal and ventral, roots are both affected.(13)

Although specific antibody testing is rarely performed, it can uncover antibodies to GM1, GM1b, GD1a, and GalNac-GD1a.(13) Anti-GalNac-GD1a antibodies in particular are implicated with the acute motor axonal neuropathy variant. GQ1b ganglioside antibodies are found in Miller Fisher Syndrome.

Table 1. Diagnostic Features of GBS
I. Required for Diagnosis
  • Progressive motor weakness in more than one extremity.
  • Areflexia. Loss of ankle-jerk with hypo-reflexia of biceps and knee jerks will suffice if other features are consistent.
II. Strongly Supportive of Diagnosis
  • Progression. Weakness develops rapidly but ceases by 4 weeks.
  • Relative symmetry
  • Mild sensory signs or symptoms.
  • Cranial nerve involvement.
  • Recovery, typically begins 2-4 weeks after progression stops.
  • Autonomic dysfunction.
  • Absence of fever at the onset of symptoms.
  • Variants
    • 1. Fever at onset of symptoms.
    • 2. Severe sensory loss with pain.
    • 3. Progression beyond 4 weeks.
    • 4. Lack of recovery or major residual deficit remaining.
  • Sphincter dysfunction. Transient bladder paralysis may occur.
  • Central nervous system involvement.
III. Features Casting Doubt on Diagnosis
  • Marked, persistent asymmetric weakness.
  • Persistent bladder or bowel dysfunction.
  • Bladder or bowel dysfunction at onset.
  • More than 50 mononuclear leukocytes/ cu mm in CSF.
  • Presence of polymorphonuclear leukocytes in CSF.
  • Sharp sensory level.
IV. Features That Rule Out the Diagnosis
  • A current history of hexacarbon abuse.
  • Evidence of porphyria.
  • Evidence of lead neuropathy, and evidence of lead intoxication.
  • A purely sensory syndrome.
  • Diagnosis of a paralytic disorder.


Contributor Information and Disclosures

Shawn Aylward
Assistant professor, Nationwide Children’s Hospital,
The Ohio State University. Columbus, OH. USA

First Created : 3/6/2001
Last Updated : 4/3/2007


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