What Is Acute Flaccid Myelitis? Six Children in Minnesota Diagnosed With Rare, Potentially Deadly Disease

The Minnesota Department of Health (MDH) is investigating an outbreak of a rare but potentially deadly disease known as acute flaccid myelitis (AFM) after six children in the state were diagnosed with the condition.

AFM affects the nervous system, specifically, the central region of the spinal cord which is filled with grey matter—a type of nerve cell. It is sometimes caused by a viral infection, although environmental factors and genetic disorders may also contribute to its development.

Symptoms often include a sudden onset of muscle weakness in the arms or legs and a loss of muscle tone and reflexes, sometimes following a respiratory illness. Patients may also experience neck weakness or stiffness, drooping eyelids, facial droop, slurred speech or difficulty swallowing. In severe cases, AFM can lead to paralysis and even death.

AFM mainly affects children, for reasons which remain unclear. The recent cases in Minnesota—which were reported from the Twin cities, central Minnesota and northeastern Minnesota—involved children under 10 years of age, all of whom were hospitalized. The first of the six diagnoses was made in mid-September.

"MDH disease investigators are working aggressively with healthcare providers to gather information about the cases," the agency said in a statement. "The department is also in contact with the Centers for Disease Control and Prevention (CDC) to share information."

According to the CDC, there was a notable increase in reported cases of AFM nationwide in 2014, which investigators have linked to an outbreak of a respiratory illness in children caused by a virus known as enterovirus D 68 (EVD68).

Nevertheless, the CDC estimates that less than one in a million people in the United States will get AFM every year. In Minnesota, three cases of the disease were reported in 2014, but since then the number had dropped until the latest outbreak.

Because AFM can develop as a result of a viral infection, the MDH and CDC recommend that parents and children take basic steps to avoid infections and stay healthy. These include washing hands frequently to limit exposure to germs, covering the mouth when coughing or sneezing and staying home when feeling sick.

If you see potential symptoms of AFM in your child—for example, if they are not using their arms properly—the MDH recommends contacting a health care provider as soon as possible. There are no specific treatments for AFM, so doctors may decide on certain treatments on a case-by-case basis.