Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 32-02: Major Vaccine-Preventable Viral Infections + Key Features Download Section PDF Listen +++ +++ Essentials of Diagnosis ++ Viral illness precedes neurologic signs Flaccid paralysis usually affects upper limbs or all four limbs Enterovirus is commonly isolated; poliomyelitis must be ruled out +++ General Considerations ++ Before widespread polio vaccination in the 1950s, polio was the most common cause of acute flaccid myelitis (also known as acute flaccid paralysis) This disease has been reported throughout Africa (20 countries) The Eastern Mediterranean region (5 countries) Intermittently in Europe (Germany and France) The United States (48 states and the District of Colombia) The CDC began surveillance for acute flaccid myelitis in 2014 Since then, there have been three outbreaks in the United States The largest to date occurred in 2018, with 80 confirmed cases between January 1, 2018, and November 1, 2018 All but 1 of the cases (99%) had a preceding viral illness in the month before presentation of neurologic signs The most commonly associated viruses (among the 50 cases in which virus was isolated) were enterovirus A71 and enterovirus D68 In all instances, poliomyelitis was ruled out, but an exact cause for the acute flaccid myelitis was not always determined All suspected cases should be reported to the state health department, the CDC or both + Clinical Findings Download Section PDF Listen +++ ++ Usually a childhood disease; the average age of presentation is 5 years Cases usually present in late summer or early fall There are three clinical stages of acute flaccid myelitis A prodromal illness Acute neurologic injury Convalescence Prodrome illness typically consists of Fever Upper respiratory symptoms Gastrointestinal symptoms Neurologic symptoms Begin 1–4 weeks later Usually manifest as flaccid limb weakness with decreased reflexes Fever may recur, and the patient experiences myalgia and flaccid weakness in one or more limbs Upper extremities are affected more often than lower extremities Convalescent phase Can last for months to years Patients may experience residual muscle weakness and atrophy + Diagnosis Download Section PDF Listen +++ +++ Laboratory Findings ++ Cerebrospinal fluid analysis shows pleocytosis (white blood cells > 5/mcL) often with an elevated protein level (and a normal glucose concentration) All individuals with suspected acute flaccid myelitis should be tested for enteroviruses (including D68 and A71) and rhinovirus from relevant anatomic sites Testing for arboviruses, adenovirus, and herpesviruses should also be considered +++ Imaging ++ MRI typically shows disease of the central gray matter within the spinal cord in the location of the anterior horn cells MRIs of the brain and spinal cord should be accompanied by lumbar puncture + Treatment Download Section PDF Listen +++ ++ No specific treatment Supportive care Many adjunctive therapies have been used, including IVIG, high-dose corticosteroids, and plasmapheresis, but none have shown efficacy Long-term therapy during the convalescent phase should include physical therapy and any other necessary forms of physical rehabilitation + Outcomes Download Section PDF Listen +++ +++ Prevention ++ An effective enterovirus-A71 vaccine has been developed for children and is in phase 3 trials (NCT03865238) +++ When to Refer ++ Neurologists specializing in the management of acute flaccid myelitis can be contacted through the AFM Physician Consult and Support Portal at the following website: https://bit.ly/2Y2U3VR + References Download Section PDF Listen +++ + +Fatemi Y et al. Acute flaccid myelitis: a clinical overview for 2019. Mayo Clin Proc. 2019 May;94(5):875–81. [PubMed: 31054607] + +Guan X et al. Effectiveness and safety of an inactivated enterovirus 71 vaccine in children aged 6–71 months in a phase IV study. Clin Infect Dis. 2019 Nov 18. [Epub ahead of print] [PubMed: 31734699] + +Hübner J et al. Acute flaccid myelitis in German children in 2016—the return of polio? Dtsch Arztebl Int. 2017 Aug 21;114(33–34):551–7. [PubMed: 28855045] + +McKay SL et al. Increase in acute flaccid myelitis—United States, 2018. MMWR Morb Mortal Wkly Rep. 2018 Nov 16;67(45):1273–5. [PubMed: 30439867] + +Messacar K et al. Acute flaccid myelitis: a clinical review of US cases 2012–2015. Ann Neurol. 2016 Sep;80(3):326–38. [PubMed: 27422805]