Acute Flaccid Myelitis

Acute flaccid myelitis (AFM) is a polio-like syndrome characterized by acute inflammatory anterior horn cell disease. A widespread incidence of such cases in the United States in 2014 led to the coining of this new term. The features of AFM include a rapid onset of asymmetric extremity weakness with a proximal predominance that nadirs in 2–3 days, decreased or flaccid tone, and absent deep tendon reflexes in the affected extremities. Bulbar symptoms may occur, while mental status, sensation, and bladder and bowel function are typically preserved. A viral prodrome is typically associated. Prompt evaluation is critical for differentiating acute flaccid myelitis from other treatable causes of acute flaccid paralysis as proven treatments exist for other disorders. Supportive and neuro-rehabilitative therapy is central to the management of AFM; various immune-modulating treatments have been tried but have not shown to be effective. Long-term outcomes vary widely. A specific pathogen has not been identified in recent cases of AFM although several pathogens are known to cause a similar pattern of injury.