Sideria Hendricks is only 10 years old, but she already has suffered two strokes.

The first occurred on Christmas Eve a few years ago. Sideria suddenly couldn't speak, and her left arm and left leg went limp. She eventually recovered, but later suffered a second minor stroke.

About 3,200 strokes occur each year in children under age 18. Although strokes are among the top ten causes of death in childhood, family members and doctors often are slow to recognize symptoms, said Dr. Jose Biller, a co-author of the American Heart Association's new guidelines for managing strokes in children.

Sideria has sickle cell disease, which is among the more than 100 risk factors for strokes in babies, children and young adults, said Biller, chairman of the department of neurology at Loyola University Health System, who is treating Sideria. Although strokes are among the top ten causes of death in childhood, family members and doctors often are slow to recognize the symptoms.

Biller is co-author of new guidelines for the prevention and treatment of strokes in infants and children. He and other experts were appointed by the American Heart Association Stroke Council's Scientific Statement Oversight Committee. The guidelines are published in Stroke: Journal of the American Heart Association.

The guidelines will be the authoritative work on the management of pediatric strokes, and an "invaluable resource and educational tool for years to come," Biller said.

Strokes can occur at any age -- even before birth. According to conservative estimates, about 3,200 strokes occur each year in youths under age 18. And more than 3,000 people under age 45 die of strokes each year. This age group accounts for between 5 percent and 10 percent of all strokes. Survivors can experience lifelong learning disabilities, seizures, movement disorders, language problems, cognitive deficits and paralysis on one side of the body. Between 6 percent and 20 percent of children who have strokes die, and at least half are left with some degree of disability.

"The impact of strokes in this age group is devastating to the child or young adult, their families and society," Biller said.

In older adults, about 85 percent of strokes are "ischemic," meaning they are caused by blood clots. About 15 percent are caused by hemorrhages (bleeding). By contrast, nearly half of strokes in children are caused by hemorrhages.

Causes of hemorrhagic strokes in children include malformations of blood vessels in the brain, illicit drug use (cocaine, amphetamines, heroin, hallucinogens, amphetamine look-alikes, etc.) systemic infections, brain tumors and blood disorders such as hemophilia and sickle cell disease.

Sickle cell disease can cause several different forms of stroke. For example, misshapen red blood cells can clog the flow of blood in the brain. To reduce the risk, Sideria receives blood transfusions every three weeks. Sideria, who lives in Forest Park, Ill., will be a fifth grader in the fall.

The quicker a child or young adult is diagnosed and treated for a stroke, the better the outcome. But family members often are slow to recognize strokes. Symptoms can be more subtle in children. It's especially difficult to recognize symptoms in babies who have not begun to walk or talk.

"People don't think that children and young adults can get strokes," Biller said.

When Jean Altizer of Park Ridge, Ill., suffered a stroke at age 34, doctors initially missed the signs. "They didn't believe me," she said.

Altzier passed out three times in a week. After the third time, she could not move her left arm or leg. Her 8-year-old son called her husband, who called an ambulance. Altzier was in the hospital for 10 days. A week after being released, she suffered a second stroke. She was off work for a year. Although she has recovered most of her functions, her arm and leg are weak.

Biller determined that Altizer's strokes probably were caused by high levels of a type of cholesterol called lipoprotein (a). Altzier, now 44, takes a cholesterol-lowering drug and tries to exercise and eat a low-cholesterol diet.

"Doctors need to take peoples' complaints seriously," she said. "They need to listen to their patients."

Loyola has been named a primary stroke center by the Joint Commission, which accredits and certifies healthcare organizations and programs. The certification is awarded to centers that "make exceptional efforts to foster better outcomes for stroke care."

Biller is a professor of neurology and neurological surgery at Loyola University Chicago Stritch School of Medicine. He has been treating young people for strokes for decades. He is primary editor of the 1994 textbook "Stroke in Children and Young Adults." An updated second edition will be published in 2009.