Week 26 Case Study

• Guillain-Barré Syndrome


  Most common cause of acute flaccid paralysis in the world
• Guillain-Barré Syndrome


  • Most patients have an earlier respiratory infection before onset of progressive motor weakness
  • Autoantibodies attack structural components of the PNS
• Molecular mimicry hypothesis


  Autoantibodies are triggered by molecular mimicry after an infection
• Diagnosis


  On the basis of presenting symptoms, disease progression, nerve conduction tests and CSF analysis
• Treatment


  Immunotherapy and full recovery is possible. However disability and even death remain possible outcomes
• Divisions of the nervous system involved in GBS

  • Afferent neurons
  • Somatic neurons
  • CNS integrating centre
• Patients with classic GBS can neither feel sensations nor move their muscles, suggesting a problem in both afferent and somatic neurons, and possibly the CNS integrating centre
• Paralysis in Chinese children

  • Somatic motor neurons
  • CNS centres controlling movements
  • Muscles
• Paralysis of the muscles suggests a problem with somatic motor neurons, the CNS centers controlling movements, or the muscles themselves
• Nerve conduction test results in classic GBS

  Decreased conduction or blocked conduction due to lack of myelin causing ion leakage
• In classic GBS, you would expect decreased conduction or blocked conduction as without myelin, ions would leak out
• The paralytic condition that affected the Chinese children is probably not a demyelinating disease, as myelin loss should decrease conduction as well as block conduction
• Acute motor axonal polyneuropathy

  • Triggered by bacterial infection
  • Damage at axons of muscular junctions
  • Damages at synapses between somatic motor neurons and skeletal muscles
  • Is not a demyelinating disease
  • Has normal conduction velocity but decreased strength of action potentials