Silent Stroke Causes Found Among Sickle Cell Kids

Strokes risk factors in children with sickle cell anemia

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Silent stroke may be the most common form of brain injury in children with sickle cell anemia, a rare, painful blood disorder. Recently, researchers have been able to pinpoint the risk factors for such strokes in children.

Scientists had previously identified the risk factors for silent stroke among adult patients with sickle cell anemia, an inherited disorder in which red blood cells are crescent shaped.

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Factors that could influence silent strokes in children include elevated blood pressure and low hemoglobin, a protein inside red blood cells that carries oxygen. Boys with sickle cell anemia also appear to be at a greater risk.

In patients with sickle cell anemia, the body attempts to compensate for low hemoglobin levels by increasing blood flow to the brain, which increases the risk of silent strokes. According to the American Society of Hematology, more than a fourth of all children with sickle cell anemia suffer a silent stroke by the age of 6, and nearly 40 percent have suffered a silent stroke by the age of 14 as a result of low hemoglobin in the blood.

Identifying risk factors can aid doctors in preventing future silent strokes in children with sickle cell anemia.

Dr. Michael R. DeBaun, study author and director of the Vanderbilt-Meharry Center for Excellence in Sickle Cell Disease at Vanderbilt University, noted that children with a history of silent strokes are at risk for larger strokes. He added that children who have silent strokes are also at a higher risk of poor academic performance, and could be retained or require special education as a result.

During the study researchers analyzed data from the international, multi-center Silent Cerebral Infarct Multi-Center Clinical Trial (SIT Trial). The trial was initiated to determine the effectiveness of blood transfusions for preventing recurrent silent strokes in pediatric sickle cell anemia patients.

Investigators enrolled 814 children between the ages of 5 and 15 with sickle cell anemia, but no history of overt stroke or seizures during the SIT Trial. They reviewed clinical history and performed brain MRIs to confirm silent strokes, finding that one third, or 251 patients, had suffered silent strokes.

Additional analysis of these results found that the risk factors for the general population, including low concentrations of hemoglobin, high systolic blood pressure and male gender, were significantly linked to a higher risk of silent stroke.

Investigators are conducting additional research to determine if hydroxyurea, a treatment traditionally used to manage painful episodes that happen as a result of sickle cell anemia, can also be used to prevent silent strokes in infants.

The study was recently published in journal Blood, the Journal of the American Society of Hematology.

Reviewed by: 
Review Date: 
November 26, 2011
Last Updated:
November 30, 2011