Acute flaccid myelitis


Clinical Features[1]

  • Acute onset, focal weakness of 1 or more extremity
  • Decreased muscular tone
  • Absent or hypoactive reflexes
  • Rarely have numbness, but may have some neuropathic pain
  • Fever and other symptoms of infection by causative virus (e.g. URI symptoms, gastroenteritis)
  • In severe cases:
    • Bulbar dysfunction (dysphagia, dysarthria, dysphonia, facial weakness, ptosis)
    • Respiratory muscle weakness
    • Autonomic instability, arrythmias if cervical lesion present
  • Paralysis usually maximal at 3-5 days after onset

Differential Diagnosis



  • Evaluate for other causes of symptoms (e.g. HSV, bacterial meningitis, Guillain-Barre syndrome)
  • CSF: Pleocytosis (WBC count >5 cells/mm3), +/- elevated protein
  • MRI: spinal cord lesion, largely restricted to gray matter, spanning one or more spinal segments


  • Report suspected cases to CDC/department of health
  • Respiratory:
    • Consider intubation for airway protection if evidence of bulbar dysfunction
    • Consider NIPPV if evidence of respiratory muscle weakness (by clinical exam, hypoxia, hypercarbia, vital capacity <15 mL/kg, or NIF <30)
  • Treat neuropathic pain
  • Elevate head of bed >30 degrees
  • No evidence of benefit from corticosteroids, IVIG, plasmapheresis, or antivirals as of yet


  • Admit
  • Consider ICU admission for:
    • Respiratory muscle weakness
    • Bulbar weakness causing impaired airway protection
    • Altered mental status
    • Autonomic instability
    • Cervical lesion on MRI
    • Rapidly progressive course

See Also

External Links