Cerebral blood flow velocities and associated neurocognitive impairment in Zimbabwean children age 1-5 years with sickle cell disease: a cross sectional study

Abstract

Introduction: Children with sickle cell disease are at risk of stroke, neuro cognitive impairment and mortality if prophylactic interventions are not instituted early. Transcranial Doppler scan (TCD), a screening tool for cerebral vasculopathy, provides an opportunity for early intervention in stroke prevention and management.
Objectives: To determine the relationship between Cerebral Vascular Blood Flow Velocities (CBFv) and neurodevelopmental impairment among children with SCD.
Materials and Methods: A hospital based cross sectional study were children aged 1-5 years with SCD without clinical symptoms of stroke were recruited from the paediatric haematology clinic at Parirenyatwa Hospital. Children with stroke, receiving chronic therapeutic blood transfusion, acute illnesses, infections, and those admitted were excluded. TCD and neurodevelopment assessment were  performed on children within 6 weeks of each assessment. Cerebral Blood Flow Velocity (CBFv) was classified as normal, conditional and high. Ethical approval was granted from Medical Research Council of Zimbabwe.
Results: Of the 37 children enrolled with sickle cell disease, 32 had neurodevelopmental assessment done. The common presenting clinical features were jaundice, pallor, fever, joint swelling, chest infection and poor weight gain. Thirteen children had a haemoglobin electrophoresis confirmatory test done. Most of the children were on hydroxyurea prophylaxis 28(76%), with 10(27 %) on both penicillin and folate. The prevalence of abnormal cerebral blood flow velocity was 5%. Cognitive impairment was identified in 4(13%) children, of whom, one also had high CBFv. Children with high CBFv tended to have lower scores on receptive and expressive language scales, although differences were not statistically significant.
Conclusion: One in eight of the children with SCD aged one to five years exhibited cognitive impairment and 5% had abnormal CBFv. The findings highlight the need for a bigger study to examine the relationship between CBFv and neurodevelopmental function of children < 5 years with SCD.