Department of Radiology & Imaging, Muhimbili University of Health and Allied Sciences, Dar Es Salaam, Tanzania.
Developmental Neurosciences Section, UCL Great Ormond Street Institute of Child Health, London, United Kingdom.
Pediatr Neurol. 2020 Jun;107:64-70. doi: 10.1016/j.pediatrneurol.2019.12.008. Epub 2019 Dec 27.
Cerebral infarcts and vasculopathy in neurologically asymptomatic children with sickle cell anemia (SCA) have received little attention in African settings. This study aimed to establish the prevalence of silent cerebral infarcts (SCI) and vasculopathy and determine associations with exposure to chronic hemolysis, anemia, and hypoxia.
We prospectively studied 224 children with SCA with transcranial Doppler (TCD), and magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA). Regressions were undertaken with contemporaneous hemoglobin, reticulocyte count, mean prior hemoglobin, oxygen content, reticulocyte count, and indirect bilirubin.
Prevalence of SCI was 27% (61 of 224); cerebral blood flow velocity was abnormal (>200 cm/s) in three and conditional (>170<200 cm/s) in one. Vasculopathy grades 2 (stenosis) and 3 (occlusion) occurred in 16 (7%) and two (1%), respectively; none had grade 4 (moyamoya). SCI was associated with vasculopathy on MRA (odds ratio 2.68; 95% confidence intervals [95% CI] 1.32 to 5.46; P = 0.007) and mean prior indirect bilirubin (odds ratio 1.02, 95% CI 1.00 to 1.03, P = 0.024; n = 83) but not age, sex, non-normal TCD, or contemporaneous hemoglobin. Vasculopathy was associated with mean prior values for hemoglobin (odds ratio 0.33, 95% CI 0.16 to 0.69, P = 0.003; n = 87), oxygen content (odds ratio 0.43, 95% CI 0.25 to 0.74, P = 0.003), reticulocytes (odds ratio 1.20, 95% CI 1.01-1.42, P = 0.041; n = 77), and indirect bilirubin (odds ratio 1.02, 95% CI 1.01 to 1.04, P = 0.009).
SCI and vasculopathy on MRA are common in neurologically asymptomatic children with SCA living in Africa, even when TCD is normal. Children with vasculopathy on MRA are at increased risk of SCI. Longitudinal exposure to anemia, hypoxia, and hemolysis appear to be risk factors for vasculopathy.
镰状细胞贫血（SCA）患儿在神经系统无症状的情况下出现脑梗死和血管病变，这在非洲地区很少受到关注。本研究旨在确定无症状性脑梗死（SCI）和血管病变的发生率，并确定与慢性溶血、贫血和缺氧暴露的相关性。
我们前瞻性地研究了 224 名 SCA 患儿的经颅多普勒（TCD）和磁共振成像（MRI）及磁共振血管造影（MRA）。回归分析采用同期血红蛋白、网织红细胞计数、平均既往血红蛋白、氧含量、网织红细胞计数和间接胆红素。
SCI 发生率为 27%（224 例中有 61 例）；3 例 TCD 脑血流速度异常（>200cm/s），1 例条件性（>170<200cm/s）。血管病变 2 级（狭窄）和 3 级（闭塞）分别为 16 例（7%）和 2 例（1%）；无一例为 4 级（烟雾病）。MRA 上 SCI 与血管病变相关（比值比 2.68；95%置信区间[95%CI]1.32 至 5.46；P=0.007）和平均既往间接胆红素（比值比 1.02，95%CI 1.00 至 1.03，P=0.024；n=83），但与年龄、性别、非正常 TCD 或同期血红蛋白无关。血管病变与平均既往血红蛋白值相关（比值比 0.33，95%CI 0.16 至 0.69，P=0.003；n=87）、氧含量（比值比 0.43，95%CI 0.25 至 0.74，P=0.003）、网织红细胞（比值比 1.20，95%CI 1.01 至 1.42，P=0.041；n=77）和间接胆红素（比值比 1.02，95%CI 1.01 至 1.04，P=0.009）。
即使 TCD 正常，非洲地区神经系统无症状的 SCA 患儿中 SCI 和 MRA 上的血管病变也很常见。MRA 上有血管病变的患儿发生 SCI 的风险增加。长期暴露于贫血、缺氧和溶血似乎是血管病变的危险因素。
