In most cases, these lesions spanned more than one level of the spinal cord. Some also had acute cranial nerve dysfunction with correlating nonenhancing brainstem lesions on MRI. None of the children experienced altered mental status or seizures. None had any cortical, subcortical, basal ganglial, or thalamic lesions on MRI. Most children reported a febrile respiratory illness in the two weeks preceding development of neurologic symptoms. In most cases, cerebrospinal fluid (CSF) analyses demonstrated mild-moderate pleocytosis (increased cell count in the CSF) consistent with an inflammatory or infectious process. Causes
As of October 2018, the U.S. CDC regarded the cause of AFM as having "a variety of possible causes such as viruses, environmental toxins, and genetic disorders", listing poliovirus, nonpolio enteroviruses, West Nile virus, and adenoviruses among the potential causes. More than 90% of people with AFM reported having symptoms consistent with a mild viral infection before the onset of AFM.Much research has focused on the nonpolio enteroviruses 68 (EV-D68) and 71 (EV-A71), a common cause of hand, foot, and mouth disease in infants and young children, members of the enterovirus D and enterovirus A species, respectively, as suspected causes. Some evidence supports a causal role of EV-D68. Coxsackievirus A16 may also play a role in some cases.A 2014 Morbidity and Mortality Weekly Report  report noted the difficulty of establishing causation by the virus.
CDC urges healthcare providers to consider EV-D68 as a possible cause of acute, severe respiratory illness and a potential increase in AFM cases. Diagnosis
AFM is diagnosed by examining a persons nervous system in combination with reviewing images of the spinal cord. A doctor can examine a persons nervous system and the places on the body where he or she has weakness, poor muscle tone, and decreased reflexes. In addition, a doctor can do magnetic resonance imaging to look at a persons brain and spinal cord, do laboratory tests on the cerebrospinal fluid (CSF, the fluid around the brain and spinal cord), and may check nerve conduction (impulse sent along a nerve fiber) and response.Diagnosis of AFM requires acute onset limb paralysis and at least one gray-matter spinal-cord lesion. CSF should show pleocytosis. Prevention
The CDC recommends, "To prevent infections in general, persons should stay home if they are ill, wash their hands often with soap and water, avoid close contact (such as touching and shaking hands) with those who are ill, and clean and disinfect frequently touched surfaces." Treatment
Treatment involves supportive care. Physical therapy may be recommended. Occasionally mechanical ventilation is required to support breathing.If immunoglobulin, corticosteroids, plasma exchange, or antiviral medication are useful is unclear. Outcomes
Studies from 2014 to 2017 indicated a poor outcome for many cases.