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Hématologie

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Stroke in sickle cell disease patients: transcranial Doppler and magnetic resonance imaging Volume 14, issue 1, janvier-février 2008

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Service de pédiatrie, Centre Hospitalier Intercommunal de Créteil, Service d’imagerie médicale, Centre Hospitalier Intercommunal de Créteil Centre de référence commun des syndromes drépanocytaires majeurs

Sickle cell disease (SCD) is the most frequent cause of stroke occurrence during infancy and strokes are the most serious complication of SCD in children. Distal vasculopathy related to sludge explains 25% of strokes in SCD whereas proximal vasculopathy is responsible for 75% of strokes. The stenoses observed in this proximal vasculopathy are progressive and can be detected by transcranial Doppler (TCD), a reliable, non-invasive and low-cost methodology. High velocities ≥ 2 m/sec are predictive of a 40% risk of stroke within 36 months but initiation of a transfusion program maintaining the HbS levels under 30% significantly reduces the risk to less than 2%. Systematic use of TCD in all children at 12-18 months of age is critical for early detection of cerebral vasculopathy, thereby preventing strokes and avoiding sequellae. Such approach was adopted in our Center at Créteil and results from a cohort of SCD newborns screened at birth showed a significant decrease in the risk of stroke from the expected 11% at 18 years to less than 2%. Distal vasculopathy is detectable by MRI, which can show ischemic silent infarcts for which a preventive treatment is currently under evaluation. These silent infarcts are associated with cognitive deficiencies compromizing future socio-professional insertion. Magnetic resonance angiography (MRA) can also detect stenoses; nevertheless; it does not substitute for TCD as abnormal high velocities precede the apparition of stenoses. Thus, TCD remains the best predictive test for assessing the risk of stroke in children with SCD.