II. Epidemiology
- First reported in California, 2012
- Outbreaks have occured in late summer and early fall (2014, 2016, 2018)
- Median age: 9 years old (some patients have been over age 21 years old)
III. Pathophysiology
- Gray matter destruction typically related to Viral Infection
IV. Symptoms
- Viral prodrome
- Meningeal symptoms may occur
- Headache
- Neck stiffness
- Myalgias
- Preserved mental status (no encephalopathy in most cases)
- Rapidly progressive and persistent weakness (follows fever by 3-7 days)
- Weakness peaks by 5 days after the weakness starts
- Bilateral in most cases
- Respiratory Failure may occur (requiring Mechanical Ventilation)
- Upper extremity involvement more common than lower extremity weakness
- Quadriplegia may occur
- Neurogenic bowel or Bladder
- Cranial Nerve Involvement may be present
- Facial weakness
- Extraocular Movement weakness (Ophthalmoplegia)
- Dysarthria
- Dysphagia
- Sensory deficits
- Focal Paresthesias
V. Causes
- See Transverse Myelitis
- Enterovirus D68 and A71
- Other non-polio Viral Infections
VI. Labs
- Obtain labs to evaluate differential diagnosis (e.g. CBC, Chemistry panel)
- Enterovirus nasopharyngeal swabs
- Cerebrospinal Fluid
- Pleocytosis may be present
VII. Imaging
VIII. Differential Diagnosis
- See Transverse Myelitis
- See Acute Flaccid Paralysis
- See Floppy Infant
- Polio
- Guillain Barre Syndrome
- Tick Paralysis
- Cerebrovascular Accident
-
Acute Demyelinating Encephalomyelitis (ADEM)
- White matter degeneration with Ataxia, Hemiplegia, confusion, encephalopathy
IX. Management
- Intravenous Immunoglobulin
- Other measures that have been used with variable efficacy
X. Prognosis
- Complete recovery is uncommon
- Most patients will be left with residual deficits
XI. References
- (2019) EM:Rap 19(2): 16-7
- (2019) Polio and other Infectious Causes of Acute Flaccid Paralysis, UpToDate, accessed 2/7/2019