Cases of children who developed a sudden weakness in one or both of their arms or legs have surged in the United States, according to the Centers for Disease Control and Prevention (CDC).

Although not all cases were directly linked to the recent enterovirus D68 outbreak earlier this year, the numbers were significantly higher during the outbreak than before or after, several experts said.

Data from CDC revealed that 120 children across the country reportedly experienced weakness in one or more of their limbs. All these reports were recorded from August 2014 to July of this year.

A magnetic resonance imaging (MRI) scan showed that this polio-like condition, known as acute flaccid myelitis (AFM), is characterized by an inflammation of the gray matter in the spinal cord. The illness was previously referred to as neurologic illness with limb weakness before being recognized as AFM.

An Unlikely Connection

Of the 120 AFM cases in the U.S., 59 were reported in California, the CDC said.

The state's Public Health department said the root cause for the illness is still unclear for doctors, but some of these California cases were linked to the D68 outbreak. The California cases were recorded during August 2014 to January 2015, a period that coincided with the enterovirus outbreak.

The connection has sparked investigations by the CDC, but no stable conclusions were made.

In a study featured in the Journal of the American Medical Association, Dr. Keith Van Haren of Stanford University and his colleagues examined the cases in California and found that 54 of the AFM patients had some form of respiratory or gastrointestinal illness before the limb weakness set in.

Enterovirus D68 is a certain form of respiratory illness. However, Van Haren said that despite isolating enterovirus D68 from serum, respiratory, and stool samples from nine AFM patients, he and his team did not find traces of it in the patients' cerebrospinal fluid.

The connection is still undetermined, Van Haren said, but he noted that the AFM cases are very similar to cases that occurred after outbreaks of polio and A71.

"We have to acknowledge the cases are not definitively proven," said Van Haren. "The reasons may include that the virus was never in the cerebrospinal fluid, that the virus had been in the cerebrospinal fluid and already left, or that this is not caused by an enterovirus."

Other Findings

Van Haren and his colleagues also found several different observations regarding the illness:

1. Aside from gastrointestinal or respiratory illness, symptoms that accompanied AFM included fever and muscle pain in the limbs.

2. The limb weakness seems to be long-term. When the team conducted a follow-up on 45 of the patients, 38 of them still had muscle weakness. The persistent limb weakness lasted for an average of nine months after diagnosis. With that, Van Haren said that very few AFM patients recover from their illness and many still remain weak. He said persistent weakness is consistent in recovering patients. Some of the cases get a little better, but most do not make full recovery, he said.

3. MRI scans could be utilized to detect and distinguish future cases, because AFM shows up on them. Van Haren said the damage looks like a bright spot running down from the center of the spinal cord.

The CDC meanwhile said the average age of the kids affected by AFM was seven years old. Some of the kids were taken care at hospitals, while some had to use breathing machines.

What the CDC Is Doing To Counter the Illness

By working with healthcare professionals, the CDC is conducting further studies on the potential causes of the illness and how frequent it had occurred.

Experts are also educating policymakers, healthcare professionals, and partners about the illness through health alerts and the Morbidity and Mortality Weekly Report.

The CDC suggests that parents who notice the symptoms of AFM on their kids should immediately take them to their healthcare provider.

To protect yourself from possible infections, the CDC advises general and proper hand-washing, avoiding contact with sick patients, and frequent disinfecting of touched surfaces.

Photo : Ano Lobb | Flickr