State health officials have issued an alert to doctors after six Minnesota children were diagnosed with a rare, polio-like disorder that causes reduced mobility or paralysis in the arms and legs.

All six cases of acute flaccid myelitis (AFM) have been reported since Sep. 20, prompting the Minnesota Department of Health to ask doctors to be on the lookout for the disorder, which has severe consequences but mysterious origins.

"It is very rare and it is certainly something we're taking very seriously," said Kris Ehresmann, who directs the Health Department's infectious disease section. "It's a very devastating situation" for the children and their families, she said.

The disease attacks the nervous system via the spinal cord, and may be transmitted by a virus. Symptoms usually include a sudden onset of arm or leg weakness and loss of muscle reflexes, but can also include drooping eyelids, slurred speech and difficulty swallowing. Treatment and therapy restores lost mobility in some children over time, but the syndrome can be fatal in those who lose the muscular function to breathe.

James Hill of Lakeville said his son, Quinton, suffered typical cold symptoms at the start of one school week last month. By the end of the week, he was vomiting and stayed home. By the weekend, his left arm and neck had stiffened badly.

Because the disorder is rare — afflicting less than one in a million children — doctors at Children's Hospital weren't considering it initially, Hill said. They conducted blood tests, imaging scans and a spinal tap to arrive at a diagnosis.

"Super scary for us," he said. "We had never heard of it. No one had ever heard it."

AFM came to the attention of the U.S. Centers for Disease Control and Prevention (CDC) in 2014 after clusters of cases were discovered in Colorado and California and linked to the spread of a type of virus known as EV-D68.

States have since reported 362 cases, some with no viral presence and some that seemed linked to other West Nile-type viruses.

The six Minnesota children, all 10 and younger, were hospitalized due to their conditions. They come from the Twin Cities, central Minnesota and northeastern Minnesota. Several of the parents contacted the Star Tribune directly, hoping that news coverage would prompt parents to take precautions and doctors and hospitals to identify the condition quickly when they encounter it.

Ehresmann said she hopes that closer study of the children — and any other cases uncovered through the latest alert to doctors — could uncover causes.

"We're looking into any kind of commonality, but at this point … we don't have anything to wrap up in a bow," she said.

The cases aren't even verified by lab test results. Ehresmman said it's the "constellation of symptoms" that ties them together.

Mario Bros.

Elaine Young's 4-year-old son, Orville, was perhaps the first case in the Minnesota cluster. Last July he came down with typical cold symptoms, which quickly gave way to immobility in his legs and paralysis in his upper right arm. Limited muscular activity in his diaphragm also restricted his breathing, at first, which can be a fatal complication of AFM.

Young said doctors delivered a diagnosis fairly rapidly — after initially ruling out a stroke — when she took Orville to the University of Minnesota Masonic Children's Hospital, where a neurologist had written a paper on AFM. But confronting one of the first Minnesota cases, she had to find out what to do next on her own, she said, and found her way to Gillette Children's Specialty Services in St. Paul.

Physical rehabilitation combined with electrical muscular stimulation there over the past two months helped Orville regain 90 percent of his leg function. The top half of his right arm remains immobile, though.

"It definitely affected me and his father much more, emotionally, at least, because we can see into his future," Young said. "When you're 4 … every time you wake up it's a big new change. So losing the use of your arm? He said: 'I can't give really good hugs anymore, but I'm doing all of my exercises!' "

Orville still plays Donkey Kong and Mario Bros. video games, his favorites, because he has use of his right wrist and lower arm.

Hill has seen some recovery in his son, even only a week after being hospitalized, with therapy at Gillette. Unable to move his upper left arm, Quinton drags it forward so he can reach Legos and build with both hands. The muscles on the left side of his face remain weak, making it hard to smile, blink and swallow.

Both children are at risk for a complication known as subluxation, or the dislocation of their dormant arms, if they don't keep them moving.

"Keep lefty involved with righty," therapists tell Quinton.

Three cases in 2014

While this is the largest cluster to be reported in Minnesota, it is not the first in the state. Minnesota had three cases in 2014, and single cases in some years since then. Nationally, most cases have been reported each year in September.

In addition to viruses, health officials suspect the syndrome is linked to unknown genetic and environmental factors. Treatments include steroid medications and immunoglobulin infusions to boost the child's immune system.

Most cases start with cold symptoms followed by loss of movement on one side of the body, and can be verified by imaging scans that detect inflammation in a central part of the spinal cord, said Dr. Anu Kalaskar, an infectious disease specialist at Children's. But treatment varies with each case, and has involved respiratory support for children struggling to breathe.

The risk of transmission is low and can be further reduced by standard cold prevention practices such as washing hands and covering coughs, she said.

The CDC has been collaborating with researchers to understand AFM, to estimate how many cases occurred before 2014, and to determine why cases increased substantially starting that year.

Mehdi Ayouche's 5-year-old daughter, Sophia, is still hospitalized at Children's in Minneapolis. The Chanhassen father worries that lost mobility in her neck and right arm might make it hard for her to do the things she loves — from swimming and drawing to Tae Kwon Do. He is hopeful that therapy will help, and relieved that Sophia's twin brother and older sister did not get the syndrome, despite having cold symptoms.

"We want to make people aware," he said. "It is a rare condition. [When it occurs], people might not know what to do next."