Hypertensive Encephalopathy in Children with Sickle Cell Disease.

Cerebrovascular (CVA) accidents are a serious complication of Sickle Cell Disease (SCD). Acute cerebral infarction occurs in approximately 10% of children with SCD under the age of 16 years, with silent infarcts identified in an additional 22%. Children however can present with acute neurologic deterioration mimicking a CVA but demonstrate a picture consistent with hypertensive encephalopathy (HTNE). The incidence of HTNE in children with SCD is unknown with few annedoctal reports available in the literature. We retrospectively identified 83 children with SCD, who received their care at Children’s National Medical Center in Washington, DC, from 1992 to 2005, who presented with neurologic complaints that prompted Magnetic Resonance Imaging (MRI). There were 37 females and 46 males, age 13 months to 17 years, with mean age of 5 years and 8 months. Clinical and neuro-imaging data identified 8 children (7 females and 1 male) with clinical picture compatible with HTNE (BP > 2 std deviation for age), prior to neuroimaging. At the time of the hypertensive episode, the ages ranged from 6 to 16 years and 8 months, with an average of 14 years and 2 months. All patients had Hb SS. Neurologic complaints included seizure, sudden onset headache, confusion, loss of consciousness, and urinary retention. Elevated blood pressures were aggressively treated and all patient received an exchange transfusion. No specific etiology for the hypertension was determined. Initial MRI, obtained within 24–48 hours of presentation, did not show acute or prior infarction in this group. However, there was absence of diffusion restriction on T1 and T2 weighted images, and presence of cerebral cortical edema, which differentiate HTNE from acute infarction. The magnetic resonance angiogram (MRA) did not demonstrate evidence of arteriopathy. The hallmark of HTNE is a complete resolution of abnormalities of both the neurologic exam and the imaging studies at follow up. There was complete resolution of cerebral edema in all patients and mild interval prominence of the cerebral sulci, which can indicate cerebral volume loss, in three out of the 8 patients, in follow up studies obtained 10 days to 4 months later. No recurrences of the symptoms have been reported, with follow up ranging from 5 months to 8 years. None of the patients with HTNE has received chronic transfusions. We conclude that HTNE should be considered in the differential diagnosis of an acute neurologic event in a child with SCD. Accurate recording of vital signs and prompt correction of hypertension is indicated. MRI can accurately distinguish between HTNE and acute infarction, even when clinical symptoms are similar. This distinction helps physicians to establish proper treatment such as chronic transfusion following infarction.