Acute flaccid myelitis

• Polio-like illness, subset of transverse myelitis
• More common in children
• Likely caused by:
  • Enterovirus, particularly Enterovirus D68, poliovirus
  • West nile virus
  • Adenovirus

• 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, arrhythmias if cervical lesion present
• Paralysis usually maximal at 3-5 days after onset

[2]

• 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
  • Spinal cord lesions may not be present on initial MRI if performed within the first 72 hours of onset of acute limb weakness.

• 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

• Weakness
• Enterovirus D68
• Transverse myelitis

https://wwwn.cdc.gov/nndss/conditions/acute-flaccid-myelitis/case-definition/2018/