Acute flaccid paralysis

Background

Epidemiology

• In Canada, 27 to 51 cases nationally every year
• Enterovirus D68 May have a biennial pattern with peaks every 2 years

Clinical Presentation

• Defined as sudden onset of muscle weakness or paralysis
  • Flaccid or hypotonic, rather than hypertonic
  • No other obvious cause, such as trauma
• Excludes transient weakness
• In acute flaccid myelitis, there are changes seen on MRI of the spinal cord

Differential Diagnosis

• About half of cases in Canada are eventually diagnosed with Guillain-Barré syndrome and 20% with transverse myelitis

Guillain-Barré Syndrome and Paralytic Poliomyelitis

	Guillain-Barré syndrome	Paralytic poliomyelitis
Fever	afebrile	febrile with myalgias
Progression	subacute, days to weeks	acute, peaks at 2-4 days
Neurological deficits	ascending, symmetric muscle weakness with decreased DTRs	asymmetric weakness with increased DTRs; proximal more than distal, and legs more than arms
Sensory changes	mild disturbances or paresthesias	none
CSF findings	minimal or no pleocytosis, but elevated protein (albuminocytologic dissociation)	pleocytosis with elevated protein, normal glucose (aseptic meningitis)

Exhaustive List

• Infection
  • Viral
    • Picornaviridae
      • Enterovirus A71
      • Enterovirus D68
      • Coxsackievirus A7
      • Poliovirus
    • Flaviviridae: West Nile virus, Japanese encephalitis, tick-borne encephalitis
    • Herpesviridae: CMV, EBV, VZV
    • HIV-related opportunistic infections
    • Rabies
  • Bacteria
    • Borrelia burgdorferi
    • Corynebacterium diphtheriae
    • Clostridium botulinum
    • Mycoplasma pneumoniae
• Neuropathy
  • Guillain-Barré syndrome, though it is typically symmetrical and bilateral ascending paralysis that may include loss of sensation
  • Acute motor axonal neuropathy
  • Critical illness neuropathy
  • Lead poisoning
  • Other heavy metal poisoning
• Spinal cord
  • Acute transverse myelitis
  • Acute spinal cord compression
  • Trauma
  • Infection
• Neuromuscular junction
  • Myasthenia gravis
• Muscle
  • Polymyositis
  • Viral myositis
  • Post-infectious myositis
  • Critical illness myopathy
• Functional

Investigations

• CBC
• Imaging: CT head, MRI brain
• CSF for routine, and especially for virology
• Viral (especially enteroviral) PCR from CSF, nasopharyngeal swab, and/or stool
  • Stool sample is sent in unpreserved, simple sterile container
  • If Enterovirus PCR is positive, can request specific PCR or sequencing for poliovirus, EV D68, and EV A71

Management

• All cases of acute flaccid paralysis are reportable in Ontario