Silent cerebral infarcts in sickle cell anemia: A risk factor analysis

Background. Silent infarcts have been reported in 17% of young patients wit h sickle cell disease and are associated with impaired performance on stand ardized psychometric tests. Risk factors for the development of these lesio ns have not been identified. Methods. Investigators in the Cooperative Study of Sickle Cell Disease perf ormed a brain magnetic resonance imaging scan on sickle cell anemia patient s age 5.9 years and older who had been followed according to the protocols of the Cooperative Study since birth. Individuals with a known history of c erebrovascular accident were excluded from this analysis. Patients with and without silent infarctions were compared with regard to clinical and labor atory parameters. Results. The study sample included 42 patients (18.3%) with silent infarcts . Patients who had silent infarcts were significantly more likely to have a clinical history of seizure and a lower painful event rate. Lower hemoglob in level, increased leukocyte count, elevated pocked red blood cell count, and SEN beta(s) globin gene haplotype were associated also with the presenc e of silent infarcts. There was no relationship between silent infarcts and platelet count, fetal hemoglobin level, reticulocyte percentage, serum asp artate aminotransferase level, total bilirubin concentration, blood pressur e, growth parameters, or presence of cu-thalassemia. A multivariate model f or silent infarction identified the following as risk factors: low pain eve nt rate, history of seizure, leukocyte count greater than or equal to 11.8 x 10(9)/L, and the SEN beta(s) globin gene haplotype. Conclusions. Patients with risk factors for silent infarcts should be evalu ated for cerebrovascular disease. If evidence of infarction is found, consi deration must be given to therapeutic intervention. At present, the appropr iate treatment has not been determined.