Acute Flaccid Myelitis (AFM) Provider Information
Acute flaccid myelitis (AFM) is a syndrome characterized by rapid onset of flaccid weakness in one or more limbs and distinct abnormalities of the spinal cord gray matter on magnetic resonance imaging (MRI).
Beginning in the summer and fall of 2014, an apparent increase in reports of AFM occurred in the United States, and standardized surveillance was established in 2015 to monitor this illness and attempt to estimate the baseline incidence. Data collected since the establishment of standardized surveillance helped with the identification of another increase in reports nationally during 2016 and has provided additional valuable information on the clinical presentation to help better characterize the clinical features, epidemiology, and short-term outcomes of cases of AFM.
An illness with onset of acute flaccid weakness.
- Confirmatory Laboratory Evidence:
- Magnetic resonance image (MRI) showing spinal cord lesions largely restricted to the gray matter*ꝉ and spanning one or more vertebral segments
- Supportive Laboratory Evidence:
- Cerebral spinal fluid (CSF) with pleocytosis (white blood cell count >5 cells/mm3)
- Clinically compatible case AND
- Confirmatory laboratory evidence (MRI showing spinal cord lesions largely restricted to the gray matter*ꝉ and spanning one or more vertebral segments)
- Clinically compatible case AND
- Supportive laboratory evidence: CSF showing pleocytosis (White blood cell count >5/mm3)
- Case classification will be verbally reported to the health department by the CDC.
* Spinal cord lesions may not be present on initial MRI; a negative or normal MRI performed within the first 72 hours after onset of limb weakness does not rule out AFM. MRI studies performed 72 hours or more after onset should also be reviewed if available.
† Terms in the spinal cord MRI report such as “affecting mostly gray matter,” “affecting the anterior horn or anterior horn cells,” “affecting the central cord,” “anterior myelitis,” or “poliomyelitis” would all be consistent with this terminology.
The CDC asks that providers continue to watch for suspect cases of AFM and send all patient information the local health department. Data collected since the development of standardized surveillance has helped to better characterize the clinical features, epidemiology, and short term outcomes of AFM.
Suspect AFM cases in Maricopa County should be reported to the Maricopa County Department of Public Health, Office of Epidemiology (602-506-6767). Information can be faxed to 602-375-8935.
The provider should work with the Maricopa County Department of Public Health disease investigator to complete the Acute Flaccid Myelitis: Patient Summary Form. The form can be accessed at https://www.cdc.gov/acute-flaccid-myelitis/downloads/patient-summary-form.pdf.
The completed form can be faxed to Maricopa County Department of Public Health at 602-372-8935.
Information requested by the Maricopa County Department of Public Health includes:
- Admission and discharge notes
- Neurology and infectious disease consults
- MRI reports
- MRI images of the brain and spinal cord on disc
- Supportive laboratory evidence: CSF showing pleocytosis (white blood cell count > 5/mm3)
Please notify Maricopa County Department of Public Health if AFM is suspected, and we will assist with specimen submission.
Prompt specimen collection is critical to provide the best chance of identifying a cause. Providers should collected specimens for patients with suspected AFM as soon as possible to the date of onset of limb weakness. Specimens to be collected for AFM classification include:
- Whole stool
- Respiratory nasopharyngeal (NP) or oropharyngeal (OP) swab
In the event of death, specimens include:
- Fresh-frozen tissue
- Formalin-fixed or formalin-fixed paraffin embedded tissue
Instructions for specimen collection, storage, and shipping can be found in the Physician Job Aid sheet.
Case classification will be verbally reported by the CDC to the health department.
Results for special studies will be batched and results returned as sample amount allows. No individual results will be reported for studies using serum. Individual polio virus and EV/RV results from testing of stool specimens will be returned as testing is completed. EV/RV results from testing of respiratory samples will be returned when completed.