Acute silent cerebral infarction in children with sickle cell anemia

Silent cerebral infarctions (SCI) occur in up to 35% of children with sickle cell anemia (HbSS) but are rarely recognized during the initial 10–14 days when diffusion weighted magnetic resonance imaging (MRI) can differentiate acute infarctions from remote events. We report acute SCI in seven children with HbSS who had areas of restricted diffusion on MRI without persistent focal neurologic deficits. Four had acute SCI identified following acute anemic events. Our observations suggest that SCI are detectible in the acute phase, present with subtle neurologic symptoms, result in permanent neurologic injury, and may be caused by acute anemic events. Pediatr Blood Cancer 2010;54:461–464. © 2009 Wiley‐Liss, Inc.     

Hydroxyurea use among children with sickle cell anemia

This study describes hydroxyurea use among children ages 1 to 17 with sickle cell anemia (SCA) enrolled in at least one year of Medicaid in six states from 2005 to 2012. Administrative claims were used to summarize the number of days’ supply of hydroxyurea dispensed by state and year. A total of 7963 children with SCA contributed 22 424 person‐years. Among person‐years with greater than 30 days of hydroxyurea, only 18% received at least 300 days of hydroxyurea, which varied by state. Following updated recommendations for all children with SCA to be offered hydroxyurea, strategies to increase hydroxyurea adherence among this population are needed.     

Bone mineral density in children with sickle cell anemia

PURPOSE: We evaluated bone mineral density (BMD) and risk factors for poor bone mineralization in children with sickle cell anemia (SCA). PATIENTS AND METHODS: Twenty-five children with severe manifestations of SCA (frequent hospitalizations, growth delay, or need for chronic red cell transfusions) were enrolled. Bone density was assessed at lumbar spine and proximal femur with dual-energy X-ray absorptiometry (DXA), and Z-scores were calculated by comparison with age, sex, and ethnicity-specific reference data. RESULTS: The median age of the study population was 12.8 years (10.2-19.8 years). Calcium intake was inadequate in 60%, and serum 25-hydroxy vitamin D (25-OHD) level <50 nM in 74% of patients. Median Z-scores for lumbar spine (-2.3) and proximal femur (-1.7) were markedly reduced, and 64% (95% confidence interval, 43%-82%) of patients had low bone density. Z-scores were not related to age, growth delay, chronic transfusions, or ferritin level. CONCLUSION: Our results suggest that children with severe manifestations of SCA have low BMD, and possess significant deficits in dietary calcium and circulating vitamin D.     

Transfusion‐transmitted babesiosis leading to severe hemolysis in two patients with sickle cell anemia

The intracellular parasites Babesia microti and Babesia duncani can be transmitted by blood transfusion and cause severe life‐threatening hemolytic anemia in high‐risk patients, including those with sickle cell disease. The rarity of the diagnosis, as well as its similar clinical presentation to delayed hemolytic transfusion reaction, may lead to a delay in diagnosis, as well as inappropriate treatment with steroids or other immunosuppressive agents. The morbidity caused by this disease in especially vulnerable populations justifies the need for a universal blood‐screening program in endemic areas.     

Arterial spin-labeled perfusion combined with segmentation techniques to evaluate cerebral blood flow in white and gray matter of children with sickle cell anemia

Background

Changes in cerebral perfusion are an important feature of the pathophysiology of sickle cell anemia (SCA); cerebrovascular ischemia occurs frequently and leads to neurocognitive deficits, silent infarcts, and overt stroke. Non‐invasive MRI methods to measure cerebral blood flow (CBF) by arterial spin labeling (ASL) afford new opportunities to characterize disease‐ and therapy‐induced changes in cerebral hemodynamics in patients with SCA. Recent studies have documented elevated gray matter (GM) CBF in untreated children with SCA, but no measurements of white matter (WM) CBF have been reported.

Procedures

Pulsed ASL with automated brain image segmentation‐classification techniques were used to determine the CBF in GM, WM, and abnormal white matter (ABWM) of 21 children with SCA, 18 of whom were receiving hydroxyurea therapy.

Results

GM and WM CBF were highly associated (R² = 0.76, P < 0.0001) and the GM to WM CBF ratio was 1.6 (95% confidence interval: 1.43–1.83). Global GM CBF in our treated cohort was 87 ± 24 mL/min/100 g, a value lower than previously reported in untreated patients with SCA. CBF was elevated in normal appearing WM (43 ± 14 mL/min/100 g) but decreased in ABWM (6 ± 12 mL/min/100 g), compared to published normal pediatric controls. Hemispheric asymmetry in CBF was noted in most patients.

Conclusions

These perfusion measurements suggest that hydroxyurea may normalize GM CBF in children with SCA, but altered perfusion in WM may persist. This novel combined approach for CBF quantification will facilitate prospective studies of cerebral vasculopathy in SCA, particularly regarding the effects of treatments such as hydroxyurea. Pediatr Blood Cancer 2009;52:85–91. © 2008 Wiley‐Liss, Inc.