What is AFM?
Acute flaccid myelitis (AFM) is an illness characterized by acute onset of flaccid limb weakness and magnetic resonance imaging (MRI) showing lesions in the gray matter of the spinal cord. AFM has been under investigation by health departments and the Centers for Disease Control and Prevention (CDC) for the past 4 years. Surveillance has shown us that AFM cases generally peak in the months of September and October (see https://www.cdc.gov/acute-flaccid-myelitis/afm-surveillance.html). A biennial pattern has been observed, with the majority of cases reported in 2014 and 2016, and smaller numbers reported in 2015 and 2017. If this pattern continues, we should expect to see an increase in AFM cases in 2018.
Letter to Chicago Providers September 2018
Job Aid for Clinicians 508 October 2018
Clinicians should continue to be vigilant and send information to Chicago Department of Public Health (CDPH) for all patients with sudden onset of neurologic illness associated with limb weakness that meet the case definition below for Acute Flaccid Myelitis. Clinicians should send information for patients who meet the case definition regardless of any laboratory results.
In June 2015, the Council of State and Territorial Epidemiologists (CSTE) adopted a standardized case definition for acute flaccid myelitis. The most recent case definition was updated in 2017. A patient must meet the clinical criteria below to be considered either a confirmed or probable case of acute flaccid myelitis:
To be considered a confirmed case, a patient must meet the following criteria:
- Acute onset of flaccid limb weakness, AND
- Confirmatory Laboratory Evidence: MRI showing a spinal cord lesion largely restricted to gray matter and spanning one or more spinal segments.
To be considered a probable case, a patient must meet the following criteria:
- Acute onset of flaccid limb weakness, AND
- Supportive Laboratory Evidence: Cerebrospinal fluid (CSF) with pleocytosis (white blood cell count >5 cells/mm3, adjusting for presence of red blood cells by subtracting 1 white blood cell for every 500 red blood cells present)
Guidelines for Submitting AFM Specimens to IDPH Lab
All samples should be frozen at -20°C. The IDPH Laboratory will forward the specimens to CDC on dry ice. If the specimens can’t get to the lab by Friday then ship on Monday. IDPH lab is not open on weekends.
An authorization number is required for shipping specimens to the IDPH Laboratory.
Complete the Acute Flaccid Myelitis Summary Form. If a completed form was submitted by the physician that reported the case, CDPH can provide a copy of the form to be included with the specimens. All medical records including progress notes, vaccination history and test results should accompany the AFM Summary Form. Instructions for AFM Patient Summary Form
Complete the IDPH Communicable Diseases Laboratory Test Requisition Form. On the top of the form write the authorization number that was provided by CDPH.
Complete the CDC Specimen Submission Form (CDC 50.34 DASH); enter information that is available. Each specimen requires its own requisition for for CDC processing.
Once specimens have been collected, an authorization number has been obtained, and all three required forms have been completed, ship specimens along with the three completed forms to:
Illinois Department of Public Health Laboratory
2121 W. Taylor Street
Chicago, IL. 60612
IDPH Lab Contact Number: (312) 793-4760
Clinicians or infection control practitioners that have access to enter reportable diseases into the Illinois National Electronic Disease Surveillance System (I-NEDSS) should also enter the case’s information into the system’s AFM module. Clinicians or infection control practitioners can register for a portal account here I-NEDSS Web Portal . If training is needed please contact the CDPH program contact.
For Clinical Questions or to Report Cases Contact:
The CDPH Disease Reporting Hotline at
For Program Questions Contact:
Erika Davis, MPH
Reporting: Clinicians should continue to be vigilant and send information to Chicago Department of Public Health (CDPH) for all patients with sudden onset of neurologic illness associated with limb weakness that meet the case definition for Acute Flaccid Myelitis. Clinicians should send information for patients who meet the case definition regardless of any laboratory results.
It is characterized by a sudden weakness in one or more arms or legs, along with loss of muscle tone and decreased or no reflexes. Some patients in addition to limb weakness may have:
- Facial droop/weakness
- Difficulty moving the eyes
- Drooping in the eyelid
- Difficulty with swallowing or slurred speech