Children with severe anemia at risk for silent strokes

Low hemoglobin levels put severely anemic children, especially those with sickle cell disease (SCD), at risk of silent infarctions (SI) that could cause long-term cognitive and learning deficits.

Findings presented at the American Stroke Association’s International Stroke Conference 2011 suggest that acutely anemic children with or without SCD can suffer brain damage from symptomless strokes that could be detected using magnetic resonance imaging (MRI).

Researchers used diffusion-weighted MRI to look at the brains of 52 hospitalized 2- to 19-year-old patients who presented with acute anemia (hemoglobin concentrations ≤5.5 g/dL) at a medical center in Dallas from 2007 to 2010. Patients also were evaluated by structured neurologic examination.

Researchers compared 22 severely anemic children with SCD with 30 children without SCD and similarly low hemoglobin levels (controls). They identified acute SIs (those occurring within 10 days of presentation) in about 19% of the children with SCD and found evidence of silent strokes in about 7% of the severely anemic group without the disease. Follow-up imaging revealed permanent brain injury in three-fourths of the children with SCD and acute SIs.

“These strokes are called ‘silent’ because they don’t cause you to be weak on one side or have any obvious neurologic symptoms. But they can lead to poor academic performance and severe cognitive impairments,” said lead researcher Michael M. Dowling, MD, PhD. Sickle cell disease is a blood disorder characterized by low levels of hemoglobin, the iron-containing component of red blood cells that carries oxygen. In addition to SCD, trauma, surgery, iron deficiency, and cancer such as leukemia also can cause a drop in red blood cell levels.

The researchers suggest that timely recognition of acute anemia and blood transfusion to increase hemoglobin levels could help prevent permanent brain damage in children with silent strokes. “Alterations in management may be warranted for all children with acute anemic events to identify unrecognized ischemic brain injury that may have permanent neurological and cognitive sequelae,” they said.

Dowling MM, Quinn CT, Plumb P, et al. Acute silent cerebral infarction occurs during acute anemic events in children with and without sickle cell disease [abstract]. Presented at: American Stroke Association International Stroke Conference 2011; February 9-11, 2011; Los Angeles, California. Abstract 185.