Why Is a Rare Polio-like Illness Affecting U.S. Children?
Polio-like Illness Appears Among Children
The number of confirmed cases of a rare, polio-like illness continues to rise among children in the United States. According to the Centers for Disease Control and Prevention, 196 cases of acute flaccid myelitis (AFM) were confirmed in 39 states in 2018. AFM primarily affects young children—however, the risk of getting it varies by age and calendar year with peaks occurring in late summer and fall. To help you learn more about this condition, we spoke with Dr. Jennifer Snow, medical director of the pediatric intensive care unit and department chair of pediatrics at the Spence and Becky Wilson Baptist Children’s Hospital.
What is AFM, and what are the symptoms?
While several infectious diseases can cause weakness or paralysis, such as polio and West Nile virus, AFM is not caused by polio. According to Snow, the condition is serious but rare. “Though the CDC has been tracking cases of AFM since 2014, we still don’t know what causes it,” said Snow. “There were a few cases in 2014, 2016 and then again in 2018, which is why it’s been brought to media’s attention recently. But it is still very rare—about one in a million.” Though researchers and health care professionals continue to learn about the condition, parents and caregivers can monitor children for symptoms associated with AFM. According to Snow, AFM is usually preceded by an illness. “Weakness typically follows a respiratory illness, and fever,” said Snow. “It specifically affects areas of the spinal cord and causes rapid onset weakness, typically in the arms and legs. Most patients experience loss of muscle tone and reflexes, and some have drooping eyes, facial weakness or difficulty swallowing and speaking.”
Is AFM contagious?
“Since we don't know the cause, it's hard to say with certainty if AFM is contagious or not,” said Snow. “It seems to follow the seasonal pattern of an infectious disease—it tends to peak in late summer or early fall.” According to Snow, that seasonality is consistent with other viruses, such as a group of enteroviruses that occur in the intestinal tract and cause polio and hepatitis A. “However, AFM is different because it doesn’t seem to be contagious,” said Snow. “We’ve seen reports where one child in a family has AFM, but his or her siblings don’t have it. So, while it doesn’t appear to be contagious, more research is required at this point in time.”
How is AFM diagnosed and treated?
Medical professionals diagnose AFM by examining a patient’s nervous system and reviewing MRI images of the spinal cord. “Sometimes it’s difficult to diagnose because AFM shares symptoms with other conditions,” said Snow. “Testing can help doctors rule out conditions like Guillain-Barre syndrome—a disorder where the immune system attacks the nerves.” Patients who are diagnosed with AFM receive early physical therapy and rehabilitation. “Beside supportive care, there's no specific treatment right now because we don’t know the cause,” said Snow. “Researchers have tried several treatment modalities, including steroids and medications called immune modulators, but none have been documented to be effective. However, experts are gathering a lot of data right now. Once a specific cause is identified, researchers will, hopefully, be able to determine an effective treatment.”
What are the prospects for recovery?
As researchers work to understand long-term outcomes for patients with AFM, health care professionals continue to monitor how children recover from the condition. “Some children have been documented to have a complete recovery,” said Snow. “However, other children have long-term deficits and severe weakness or paralysis of the arms, legs or respiratory muscles. Some patients require a tracheostomy and mechanical ventilation. But again, we don't have long-term data in terms of outcomes, including if those patients could eventually achieve complete recovery.” Because most AFM patients reported having a fever or respiratory illness before developing AFM, Snow advises parents and children to follow best practices for good personal hygiene to help decrease the risk of getting a viral infection. “If AFM is caused by a virus, there are steps you can take to lower the risk of viral infection, including encouraging children to cover their mouth when they cough or sneeze, maintain a healthy diet and wash their hands with soap and water. Hand washing is always an essential step to help prevent spreading germs.” Explore pediatric services at the Spence and Becky Wilson Baptist Children’s Hospital, including the pediatric intensive care unit and pediatric emergency room. Find a pediatrician by visiting our Find a Physician page.