Brain Magnetic Resonance Imaging and Angiography Findings in Ugandan Children with Sickle Cell Anemia; A Cross Sectional Study

Sickle Cell Anemia (SCA) is a leading cause of childhood stroke in sub-Saharan Africa and sickle cell brain vasculopathy manifests either as overt stroke or clinically "silent infarcts". This study aimed to describe brain abnormalities seen on magnetic resonance imaging in Ugandan SCA children. Our hypothesis was that multi-model abnormalities would be associated with cerebrovasculopathy found on MRI/MRA.

Methods

As part of a larger study to determine the burden and spectrum of neurological and cognitive impairments in SCA children in Uganda, we selected 81 children ages 1-12 years with HbSS, a sample enriched for possible brain pathology from Mulago hospital SCA clinic out of a random sample of 265 stable children. None was receiving hydroxyurea. All had detailed clinical history, and physical, neurological and cognitive testing, trans-cranial Doppler (TCD) cerebral blood flow velocity determination and non-contrasted brain MRI/MRA using a 1.5 Tesla scanner. Cognitive testing was performed using age-specific tools validated for Ugandan children.

Results

Of the 81 participants imaged, 61 had one or more of history of stroke, an abnormal neurological exam, cognitive impairment or abnormal TCD, while 20 had normal test results. MR abnormalities were seen in 35/61 (63.9%) participants with probable brain pathology and in 4/20 (20.0%) without any probable brain pathology. They included different structural abnormalities seen in all brain regions ranging from only T2 weighted hyper-intensities, white matter lacuna infarction to bilateral ischemic and multi-focal cerebral infarcts with associated compensatory hydrocephalus. MRA abnormalities ranged from cerebral microangiopathy to multiple stenosis and occlusions of major arteries, including moya-moya in 4 subjects. Severe vessel obstructions were also seen in multiple young children <36 months.

Conclusions

Brain injury in Uganda children with SCA begins early in childhood and becomes a common finding during later childhood. Early screening for stroke and intervention therapy is warranted to prevent sickle brain vasculopathy initiated early after diagnosis. The risk factors for such early brain injury should be investigated.