Dowling's research team drives effort to curb 'silent' pediatric strokes

By Rachel Skei Donihoo / March 28-31, 2011

Pediatric stroke research is in its infancy, but Dr. Michael Dowling is leading a new initiative at UT Southwestern to diagnose and treat these “silent” episodes in children, particularly those with sickle cell disease and conditions that cause severe anemia.

Dr. Michael Dowling

His efforts include research, clinical assessment and treatment of pediatric strokes, an often-misdiagnosed “brain attack” that occurs as frequently as leukemia and brain tumors but many times goes unrecognized by caregivers, despite the serious short- and long-term neurological consequences.

“Pediatric stroke research is in its early stages,” said Dr. Dowling, assistant professor of pediatrics and neurology and neurotherapeutics, as well as medical director of the pediatric stroke program at Children’s Medical Center Dallas. “We've simply got to find out why children suffer strokes and better educate parents and physicians about recognizing and diagnosing them.”

At the American Heart Association’s recent International Stroke Conference in Los Angeles, Dr. Dowling presented his research on “silent strokes,” which have few, if any, obvious symptoms but cause patches of the brain to die.

“These very young children have brains that look like the brains of 80-year-olds,” he said. “These strokes are called ‘silent’ because they don’t cause the child to be weak on one side or have any obvious neurologic symptoms, but they can lead to poor academic performance and severe cognitive impairments.”

Dr. Dowling’s research has shown that doctors may be missing strokes in a small but significant number of children with severe anemia, who may be mislabeled as slow learners. Strokes have long been known to be a risk for kids with sickle cell anemia, an inherited blood disorder. The new study found they also occurred undetected in children with other conditions that can cause severe anemia, such as cancer, kidney failure or blood loss from trauma.

Using diffusion-weighted magnetic resonance imaging, Dr. Dowling’s group found evidence of acute “silent strokes” in four of 22 children with sickle cell disease and in two of 30 children without sickle cell disease when they arrived at the hospital with severe anemia, or low blood counts.

Although the anemia had various causes, researchers found that the strokes were occurring consistently without being diagnosed. Dr. Dowling recommends that all children with severe anemia be carefully examined for strokes. Improved recognition and timely transfusion to increase blood hemoglobin levels could prevent permanent brain damage in children with strokes, according to the study.

Dr. Dowling and his team now are taking part in a national research study to test the use of tissue plasminogen activator — currently an adult-only clot-busting stroke drug — in children who have suffered strokes.