In addition to the limb weakness, some people may also experience one or more of the following symptoms:
- gait difficulty
- facial droop or weakness
- difficulty moving the eyes
- drooping eyelids
- difficulty talking or swallowing
- unable to pass urine
- pain in arms, legs, and/or neck
- numbness or tingling
The clinical presentation is similar to poliomyelitis, but the polio virus has not been detected in any specimens from patients with AFM.
AFM is considered a medical emergency as some patients can experience rapid respiratory failure and may require ventilator support.
Cause: There is no single known cause of AFM; all infectious and non-infectious etiologies are investigated. It has been primarily associated with viruses such as non-polio enteroviruses which typically cause mild illness such as a fever or respiratory infections. Other viruses, including flaviviruses, herpesviruses, and adenoviruses, are considered.
AFM can also resemble other conditions, including transverse myelitis and Guillain-Barré syndrome. For most reported cases across the US, the cause has not been identified. More research needs to be done to better understand why some people develop AFM after a viral infection and why others do not. Providers should consider a diagnosis of AFM in late summer or early fall, especially in patients with preceding viral symptoms.
Illness and Treatment: AFM is treated through supportive care, which is recommended by teams of expert health care providers on a case-by-case basis. The long-term effects of AFM are different for each person. Some people diagnosed with AFM recover quickly and completely. Others have continued weakness and require ongoing, high-level care.
Additional Risks: AFM appears to affect children more than adults. About 90% of acute flaccid myelitis cases affect children between the ages of 1 and 7.
Please note: All patients meeting the clinical criteria for AFM also meet the criteria for consideration as a possible paralytic poliomyelitis case, which is immediately notifiable to local health jurisdictions in Washington under WAC 246-101. Travel and immunization histories should be obtained as soon as possible on all suspected AFM cases to help rule out polio as a possible cause.
Purpose of Reporting and Surveillance
- To identify cases of AFM and establish an incidence baseline and burden of the condition in Washington State.
- To help identify causes of AFM in the United States.
- To understand the impact of AFM among all age groups.
Legal Reporting Requirements
- Heath care providers and Health care facilities: notifiable to local health jurisdiction within 24 hours
- Laboratories: no requirements for reporting
- Local health jurisdictions: notifiable to the Washington Department of Health (DOH) Office of Communicable Disease Epidemiology (CDE) within 7 days of case investigation completion or summary information required within 21 days. (1-206-418-5500 or 1-877-539-4344)