Central nervous system complications and management in sickle cell disease

Effect of voxelotor on cerebral perfusion and cerebral oxygen metabolism and cardiac stress in adult patients with sickle cell disease

Sickle cell disease (SCD) is complicated by silent cerebral infarcts (SCIs), for which anemia is an important risk factor. Despite normal oxygen delivery (OD), cerebral vascular reserve (CVR), and cerebral metabolic rate of oxygen (CMRO2) are diminished in SCD, possibly causing the formation of SCIs. Voxelotor inhibits polymerization by increasing the hemoglobin oxygen binding, ameliorating hemolytic anemia. Furthermore, anemia is related to cardiac complications. Our aims were to assess the effect of voxelotor on markers of cerebral perfusion, cerebral oxygen metabolism, and markers of cardiac stress in SCD patients. Cerebral hemodynamics and oxygen metabolism were measured with MRI before and after 3 months of voxelotor treatment (1500 mg/day) in 18 adults with SCD (HbSS/HbSβ0-thalassemia). Hemoglobin levels significantly increased (p = .001) and markers of hemolysis decreased (p < .05). OD increased from 6.5 (IQR, 6.0-7.1) mL O2/100 g/min to 8.1 (IQR, 7.2-8.7) mL O2/100 g/min (p = .001). CBF and CVR did not change. CMRO2 decreased from 2.0 (IQR, 1.9-2.1) mL O2/100 g/min to 1.9 (IQR, 1.6-2.1) mL O2/100 g/min (p = .03). N-terminal pro-B type natriuretic peptide (NT-proBNP) levels decreased (p = .048) and maximum tricuspid regurgitation flow velocity (TRVmax) normalized in all but one patient with increased TRVmax. Voxelotor treatment in patients with severe SCD did not decrease CBF despite increased Hb levels. Cerebral oxygen metabolism slightly decreased, despite raised OD, most likely due to drug-induced increase in oxygen binding. Nonetheless, voxelotor improved clinically validated markers of cardiac stress.

Transfusions, disease-modifying treatments, and curative therapies for sickle cell anemia in Africa: where are we now?

The mortality burden of sickle cell anemia (SCA) is centered in sub-Saharan Africa. In addition to a lack of systematic programs for early diagnosis, access to disease-modifying treatments is limited to only a few urban centers. Providing a safe and adequate blood supply is a major challenge, heightening mortality from SCA-associated complications that require urgent blood transfusion and making the delivery of regular transfusion therapy for stroke prevention nonfeasible. Hydroxyurea therapy with proven clinical benefits for pain episodes, acute chest syndrome, malaria, transfusions, hospitalizations, and stroke prevention is the most feasible treatment for SCA in Africa. Access barriers to hydroxyurea treatment include poor availability, unaffordable costs, health professionals' reluctance to prescribe, a lack of national guidelines, and exaggerated fears about drug toxicities. Strategies for the local manufacture of hydroxyurea combined with the systematic education and training of health professionals using guidelines supported by the World Health Organization can help surmount the access barriers. Hematopoietic stem cell transplantation as a curative therapy is available in only 7 countries in Africa. The few patients who have suitable sibling donors and can afford a transplant must usually travel out of the country for treatment, returning to their home countries where expertise and resources for posttransplant follow-up are lacking. The recently developed ex-vivo gene therapies are heavily dependent on technical infrastructure to deliver, a daunting challenge for Africa. Future in-vivo gene therapies that bypass myeloablation and ex-vivo processing would be more suitable. However, enthusiasm for pursuing these gene therapies should not overlook strategies to make hydroxyurea universally accessible in Africa.

Hydroxyurea to prevent brain injury in children with sickle cell disease (HU Prevent)-A randomized, placebo-controlled phase II feasibility/pilot study

Central nervous system (CNS) injury is common in sickle cell disease (SCD) and occurs early in life. Hydroxyurea is safe and efficacious for treatment of SCD, but high-quality evidence from randomized trials to estimate its neuroprotective effect is scant. HU Prevent was a randomized (1:1), double-blind, phase II feasibility/pilot trial of dose-escalated hydroxyurea vs. placebo for the primary prevention of CNS injury in children with HbSS or HbS-β0-thalassemia subtypes of SCD age 12-48 months with normal neurological examination, MRI of the brain, and cerebral blood flow velocity. We hypothesized that hydroxyurea would reduce by 50% the incidence of CNS injury. Two outcomes were compared: primary-a composite of silent cerebral infarction, elevated cerebral blood flow velocity, transient ischemic attack, or stroke; secondary-a weighted score estimating the risk of suffering the consequences of stroke (the Stroke Consequences Risk Score-SCRS), based on the same outcome events. Six participants were randomized to each group. One participant in the hydroxyurea group had a primary outcome vs. four in the placebo group (incidence rate ratio [90% CI] 0.216 [0.009, 1.66], p = .2914) (~80% reduction in the hydroxyurea group). The mean SCRS score was 0.078 (SD 0.174) in the hydroxyurea group, 0.312 (SD 0.174) in the placebo group, p = .072, below the p-value of .10 often used to justify subsequent phase III investigations. Serious adverse events related to study procedures occurred in 3/41 MRIs performed, all related to sedation. These results suggest that hydroxyurea may have profound neuroprotective effect in children with SCD and support a definitive phase III study to encourage the early use of hydroxyurea in all infants with SCD.

Beyond Ischemia: The Rare Occurrence of Hemorrhagic Strokes in Pediatric Sickle Cell Anemia

Sickle cell anemia (SCA) is a genetic disorder characterized by the production of abnormal hemoglobin S, leading to red blood cell sickling and subsequent vaso-occlusive events. Neurological complications, particularly strokes, significantly contribute to the morbidity and mortality associated with SCA. While ischemic strokes are more common, hemorrhagic strokes, though less frequent, present significant challenges, especially in the pediatric population. Understanding the complex interplay of genetic, environmental, and hematological factors is crucial for managing these cases. We report two cases of pediatric patients with SCA who experienced rare hemorrhagic strokes. The first case involves a nine-year-old male presenting with a subarachnoid hemorrhage, revealing cortical ischemia and multiple cerebral artery strictures. Early supportive measures resulted in a good clinical improvement, after which the patient underwent bone marrow transplantation. The second case describes a seven-year-old male who developed an epidural hematoma during a vaso-occlusive crisis, necessitating emergency surgical intervention. After initial persistent neurological deficits, the patient began to show gradual improvement with ongoing management, reflecting the complexity and severity of such events. Hemorrhagic strokes in pediatric SCA patients, though rare, represent significant clinical challenges due to their multifactorial etiology and complex management needs. These cases underscore the importance of a multidisciplinary approach and advanced diagnostic tools in managing hemorrhagic complications in SCA. Further research is essential to unravel the pathophysiological mechanisms and develop targeted prevention strategies to improve outcomes for this vulnerable population.

Children and Adolescents With Sickle Cell Disease and Skull Infarction: A Systematic Review

INTRODUCTION

Skull infarction is an uncommonly reported complication of sickle cell disease. We aimed to characterize the clinical and imaging features of skull infarction in pediatric patients with sickle cell disease.

METHODS

We searched the PubMed database for case reports on skull bone infarction in pediatric patients with sickle cell disease. Out of 67 records retrieved, 15 met inclusion criteria, and a 16th case reported by the senior author was included. We extracted and analyzed clinical and imaging data.

RESULTS

The most common symptom at onset was headache (88%). Bilateral skull infarction (50%) and parietal bone involvement (82%) were frequent imaging findings. Epidural hematoma developed in 65% of the cases, 30% of patients required drainage, and exchange infusion was reported in 18%. No fatal outcomes were reported.

CONCLUSIONS

Skull infarction is a potentially severe complication of sickle cell disease presenting unique clinical challenges. Acute headaches should raise suspicion for this condition and may require additional investigation.

Health Supervision for Children and Adolescents With Sickle Cell Disease: Clinical Report

Sickle cell disease (SCD) is a group of complex genetic disorders of hemoglobin with multisystem manifestations. The scope of this clinical report is such that in-depth recommendations for management of all complications is not possible. Rather, the authors present an overview focused on the practical management of children and adolescents with SCD and the complications that are of particular relevance to pediatric primary care providers. References with detailed commentary provide further information. Timely and appropriate treatment of acute illness is critical, because life-threatening complications may develop rapidly. Specialized comprehensive medical care decreases morbidity and mortality during childhood. The provision of comprehensive care is a time-intensive endeavor that includes ongoing patient and family education, periodic comprehensive evaluations and other disease-specific health maintenance services, nursing support, psychosocial care, and genetic counseling. Ideally, this care includes comanagement by the pediatrician or other pediatric primary care provider and a team of specialist SCD experts: Hematologist, other pediatric specialists, advanced practice providers, nurse specialists, social workers, patient navigators, and educational liaisons.

Navigating the Interplay of Sickle Cell Vasculopathy and Moyamoya Cerebrovascular Changes: A Case Report

Sickle cell disease (SCD) is a hereditary hemoglobinopathy that can lead to progressive vasculopathy, increasing the risk of cerebrovascular complications. Moyamoya syndrome (MMS), a rare disorder characterized by stenosis of the internal carotid arteries, can occur in SCD patients due to chronic endothelial damage and inflammation. The coexistence of these conditions can result in severe cerebrovascular complications, presenting unique diagnostic and therapeutic challenges. We present a 35-year-old African American male with a complex interplay of advanced SCD and MMS, manifesting as extensive cerebrovascular disease and recurrent ischemic strokes. A CT angiogram (CTA) of the head showed diffusely decreased caliber of the right M1 segment, appearing worse compared to prior studies. CTA of the head and neck demonstrated a new cut-off of the distal right M3 segment with an asymmetric paucity of arborizing vessels within the right middle cerebral artery (MCA) distribution, consistent with progressive sickle cell vasculopathy and also demonstrated abnormal dilated collateral vessels. Further imaging with MRI exhibited multiple prior ischemic strokes in various vascular territories despite previous revascularization surgery with a left superficial temporal artery to MCA bypass. The patient's progressive cerebrovascular disease was attributed to sickle cell vasculopathy exacerbated by MMS, resulting in compromised cerebral perfusion through distinct pathological mechanisms. Management involved a multidisciplinary treatment approach, including chronic transfusions, antiplatelet therapy, surgical revascularization with extracranial-intracranial bypass, seizure management, and neuropsychiatric support. Despite maximal therapy, the patient experienced recurrent cerebrovascular events and progressive neurological deficits, highlighting the challenges in controlling these intertwined disease processes. It signifies the importance of early recognition of this rare co-occurrence and implementation of prompt multidisciplinary treatment to improve outcomes.

Impacts of oxidative stress and anti-oxidants on the development, pathogenesis, and therapy of sickle cell disease: A comprehensive review

Sickle cell disease (SCD) is the most severe monogenic hemoglobinopathy caused by a single genetic mutation that leads to repeated polymerization and depolymerization of hemoglobin resulting in intravascular hemolysis, cell adhesion, vascular occlusion, and ischemia-reperfusion injury. Hemolysis causes oxidative damage indirectly by generating reactive oxygen species through various pathophysiological mechanisms, which include hemoglobin autoxidation, endothelial nitric oxide synthase uncoupling, reduced nitric oxide bioavailability, and elevated levels of asymmetric dimethylarginine. Red blood cells have a built-in anti-oxidant system that includes enzymes like sodium dismutase, catalase, and glutathione peroxidase, along with free radical scavenging molecules, such as vitamin C, vitamin E, and glutathione, which help them to fight oxidative damage. However, these anti-oxidants may not be sufficient to prevent the effects of oxidative stress in SCD patients. Therefore, in line with a recent FDA request that the focus to be placed on the development of innovative therapies for SCD that address the root cause of the disease, there is a need for therapies that target oxidative stress and restore redox balance in SCD patients. This review summarizes the current state of knowledge regarding the role of oxidative stress in SCD and the potential benefits of anti-oxidant therapies. It also discusses the challenges and limitations of these therapies and suggests future directions for research and development.

Neurocognitive outcome in children with sickle cell disease after myeloimmunoablative conditioning and haploidentical hematopoietic stem cell transplantation: a non-randomized clinical trial

Background

Due to the risk of cerebral vascular injury, children and adolescents with high-risk sickle cell disease (SCD) experience neurocognitive decline over time. Haploidentical stem cell transplantation (HISCT) from human leukocyte antigen-matched sibling donors may slow or stop progression of neurocognitive changes.

Objectives

The study is to determine if HISCT can ameliorate SCD-associated neurocognitive changes and prevent neurocognitive progression, determine which specific areas of neurocognitive functioning are particularly vulnerable to SCD, and determine if there are age-related differences in neurocognitive functioning over time.

Methods

We performed neurocognitive and neuroimaging in SCD recipients following HISCT. Children and adolescents with high-risk SCD who received parental HISCT utilizing CD34+ enrichment and mononuclear cell (T-cell) addback following myeloimmunoablative conditioning received cognitive evaluations and neuroimaging at three time points: pre-transplant, 1 and 2 years post-transplant.

Results

Nineteen participants (13.1 ± 1.2 years [3.3-20.0]) received HISCT. At 2 years post-transplant, neuroimaging and cognitive function were stable. Regarding age-related differences pre-transplantation, older children (≥13 years) had already experienced significant decreases in language functioning (p < 0.023), verbal intelligence quotient (p < 0.05), non-verbal intelligence quotient (p < 0.006), and processing speed (p < 0.05), but normalized post-HISCT in all categories.

Conclusion

Thus, HISCT has the potential to ameliorate SCD-associated neurocognitive changes and prevent neurocognitive progression. Further studies are required to determine if neurocognitive performance remains stable beyond 2 years post-HISCT.Clinical trial registration: The study was conducted under an investigator IND (14359) (MSC) and registered at clinicaltrials.gov (NCT01461837).

Neurocognitive impairment in Ugandan children with sickle cell anemia compared to sibling controls: a cross-sectional study

Introduction

The neurocognitive functions in Ugandan children aged 1-12 years with sickle cell anemia (SCA) were compared to their non-SCA siblings to identify risk factors for disease-associated impairment.

Methods

This cross-sectional study of the neurocognitive functions in children with SCA (N = 242) and non-SCA siblings (N = 127) used age- and linguistically appropriate standardized tests of cognition, executive function, and attention for children ages 1-4 and 5-12. Test scores were converted to locally derived age-normalized z-scores. The SCA group underwent a standardized stroke examination for prior stroke and transcranial Doppler ultrasound to determine stroke risk by arterial flow velocity.

Results

The SCA group was younger than their siblings (mean ages 5.46 ± 3.0 vs. 7.11 ± 3.51 years, respectively; p < 0.001), with a lower hemoglobin concentration (7.32 ± 1.02 vs. 12.06 ± 1.42, p < 0.001). The overall cognitive SCA z-scores were lower, -0.73 ± 0.98, vs. siblings, -0.25 ± 1.12 (p < 0.001), with comparable findings for executive function of -1.09 ± 0.94 vs. -0.84 ± 1.26 (p = 0.045), respectively. The attention z-scores for ages 5-12 for the SCA group and control group were similar: -0.37 ± 1.4 vs. -0.11 ± 0.17 (p = 0.09). The overall differences in SCA status were largely driven by the older age group, as the z-scores in the younger subsample did not differ from controls. Analyses revealed the strongest predictors of poor neurocognitive outcomes among the SCA sample to be the disease, age, and prior stroke (each p < 0.001). The impacts of anemia and SCA were indistinguishable.

Discussion

Neurocognitive testing in children with SCA compared to non-SCA siblings revealed poorer SCA-associated functioning in children older than age 4. The results indicate the need for trials assessing the impact of disease modification on children with SCA.

Montreal cognitive assessment in Brazilian adults with sickle cell disease: The burdens of poor sociocultural background

Sickle cell disease (SCD) patients are at higher risk of developing silent cerebral infarcts and overt stroke, which may reflect cognitive impairment, functional limitations, and worse quality of life. The cognitive function of Brazilian adult SCD patients (n = 124; 19-70 years; 56 men; 79 SS, 28 SC, 10 S/β0, 7 S/β+) was screened through Montreal Cognitive Assessment (MoCA) and correlated the results with possible predictive factors for test performance, including sociocultural, clinical, laboratory data and brain imaging. The Median MoCA score was 23 (8-30); 70% had a 25-or-less score, suggesting some level of cognitive impairment. There were no significant associations between MoCA results and any clinical or laboratory data in SS and SC patients; however, a significant correlation (P = 0.03) with stroke was found in HbS/β-thalassemic patients. Correlations were further detected according to sociodemographic conditions, such as age (r = -0.316; P < 0.001), age at first job (r = 0.221; P = 0.018), personal (r = 0.23; P = 0.012) and per capita familiar incomes (r = 0.303; P = 0.001), personal (r = 0.61; P = 0), maternal (r = 0.536; P = 0), and paternal educational status (r = 0.441; P = 0). We further sought independent predictors of performance using multivariable regressions and increased education was an independent predictor of better scores in MoCA (0.8099, 95% confidence interval [CI]: 0.509-1.111). Brain imaging analysis showed significant and progressive atrophy in important cerebral areas related to memory, learning, and executive function. These data point to the high prevalence and impact of cognitive decline in adult SCD patients, mirrored in brain atrophic areas. It is also possible to observe the influence of sociodemographic conditions on patients' cognitive performances and the need for creating focused therapeutic plans that address these deficiencies. Moreover, the absence of a significant correlation of MoCA values with stroke in the SS and SC groups may be related to the worst sociocultural and economic conditions of the Brazilian African descent population, in which the impact of low educational stimulation on cognitive function can outweigh even the anatomical damage caused by the disease.

Neurocognitive Impairment in Ugandan Children with Sickle Cell Anemia Compared to Sibling Controls: A cross-sectional study

Introduction

Neurocognitive function in Ugandan children aged 1-12 years with sickle cell anemia (SCA) were compared to their non-SCA siblings to identify risk factors for disease-associated impairment.

Methods

This cross-sectional neurocognitive function study of children with SCA (N=242) and non-SCA siblings (N=127) used age- and linguistically-appropriate standardized tests of cognition, executive function and attention for children ages 1-4 and 5-12 years. Test scores were converted to locally derived age-normalized z-scores. The SCA group underwent standardized stroke examination for prior stroke and transcranial doppler ultrasound (TCD) to determine stroke risk by arterial flow velocity.

Results

The SCA group was younger than siblings (mean ages 5.46±3.0 versus 7.11±3.51 years, respectively; p <.001), with lower hemoglobin concentration (7.32±1.02 vs. 12.06±1.42, p <.001). Overall cognitive SCA z-scores were lower: -0.73 ±0.98 vs. siblings -0.25 ±1.12 (p<.001), with comparable findings for executive function of -1.09±0.94 versus -0.84±1.26 (p=0.045), respectively. Attention z-scores for ages 5-12 for the SCA group and controls were similar: -0.37±1.4 vs. -0.11±0.17 (p=.09). Overall differences by SCA status were largely driven by the older age group, as z-scores in the younger sub-sample did not differ from controls. Analyses revealed the strongest predictors of poor neurocognitive outcomes among the SCA sample to be the disease, age and prior stroke (each p<.001). Impact from anemia and SCA were indistinguishable.

Discussion

Neurocognitive testing in children with SCA compared to non-SCA siblings revealed poorer SCA-associated functioning in children older than age 4. Results indicate need for trials assessing impact from disease modification for children with SCA.

Overview of the Association Between the Pathophysiology, Types, and Management of Sickle Cell Disease and Stroke

Sickle cell disease (SCD) is a genetic blood disorder that affects hemoglobin and increases stroke risk, particularly in childhood. This review examines the pathophysiological association between SCD and stroke, the classification of stroke types, risk factors, diagnosis, management, prevention, and prognosis. A comprehensive literature search was conducted via PubMed, Scopus, and Cochrane databases. Relevant studies on SCD and stroke pathophysiology, classification, epidemiology, diagnosis, treatment, and prevention were identified. Sickle cell disease causes red blood cells to become rigid and sickle-shaped, obstructing blood vessels. Recurrent sickling alters cerebral blood flow and damages vessel walls, often leading to ischemic or hemorrhagic strokes (HS). These occur most frequently in childhood, with ischemic strokes (IS) being more common. Key risk factors include a prior transient ischemic attack (TIA), low hemoglobin, and a high leukocyte count. Neuroimaging is essential for diagnosis and determining stroke type. Primary prevention centers on blood transfusions and hydroxyurea for those at high risk. Acute treatment involves promptly restoring blood flow and managing complications. However, significant knowledge gaps remain regarding stroke mechanisms, optimizing screening protocols, and improving long-term outcomes. This review synthesizes current evidence on SCD and stroke to highlight opportunities for further research and standardizing care protocols across institutions. Ultimately, a holistic perspective is critical for mitigating the high risk of debilitating strokes in this vulnerable patient population.

Prevention of neurovascular complications in children with Sickle Cell Disease in the real-world setting: What adult medicine physicians should know

Neurovascular complications represent one of the most detrimental manifestations of Sickle Cell Disease (SCD), affecting many patients since infancy. They include overt stroke, silent cerebral infarcts and neurocognitive disorders. In fact, neurodevelopment can be impaired in children resulting in cognitive dysfunction in adults with SCD. This review is meant to resume the most recent guidelines about the prevention of SCD neurovascular complications and to highlight the open challenges in their implementation. Transcranial Doppler, Magnetic Resonance Imaging/Angiography and neurocognitive test are useful screening tools. Chronic transfusion regimen, hematopoietic stem cell transplantation and neurocognitive rehabilitation find indications in the context of primary and secondary prevention of neurovascular complications of SCD. However, international guidelines are often difficult to bring into the real world due to the lack of appropriate instruments and trained personnel. Many challenges have still to be faced to guarantee the best possible neurocognitive function to each child affected by SCD.

From Stress to Sick(le) and Back Again-Oxidative/Antioxidant Mechanisms, Genetic Modulation, and Cerebrovascular Disease in Children with Sickle Cell Anemia

Sickle cell anemia (SCA) is a genetic disease caused by the homozygosity of the HBB:c.20A>T mutation, which results in the production of hemoglobin S (HbS). In hypoxic conditions, HbS suffers autoxidation and polymerizes inside red blood cells, altering their morphology into a sickle shape, with increased rigidity and fragility. This triggers complex pathophysiological mechanisms, including inflammation, cell adhesion, oxidative stress, and vaso-occlusion, along with metabolic alterations and endocrine complications. SCA is phenotypically heterogeneous due to the modulation of both environmental and genetic factors. Pediatric cerebrovascular disease (CVD), namely ischemic stroke and silent cerebral infarctions, is one of the most impactful manifestations. In this review, we highlight the role of oxidative stress in the pathophysiology of pediatric CVD. Since oxidative stress is an interdependent mechanism in vasculopathy, occurring alongside (or as result of) endothelial dysfunction, cell adhesion, inflammation, chronic hemolysis, ischemia-reperfusion injury, and vaso-occlusion, a brief overview of the main mechanisms involved is included. Moreover, the genetic modulation of CVD in SCA is discussed. The knowledge of the intricate network of altered mechanisms in SCA, and how it is affected by different genetic factors, is fundamental for the identification of potential therapeutic targets, drug development, and patient-specific treatment alternatives.

Neurofilament light chain: A potential biomarker for cerebrovascular disease in children with sickle cell anaemia

Cerebrovascular injury frequently occurs in children with sickle cell anaemia (SCA). Limited access to magnetic resonance imaging and angiography (MRI-MRA) in sub-Saharan Africa impedes detection of clinically unapparent cerebrovascular injury. Blood-based brain biomarkers of cerebral infarcts have been identified in non-SCA adults. Using plasma samples from a well-characterized cross-sectional sample of Ugandan children with SCA, we explored relationships between biomarker levels and MRI-detected cerebral infarcts and transcranial Doppler (TCD) arterial velocity. Testing was performed using a 4-plex panel of brain injury biomarkers, including neurofilament light chain (NfL), a central nervous system neuron-specific protein. Mean biomarker levels from the SCA group (n = 81) were similar to those from non-SCA sibling controls (n = 54). Within the SCA group, NfL levels were significantly higher in those with MRI-detected infarcts compared to no infarcts, and higher with elevated TCD velocity versus normal velocity. Elevated NfL remained strongly associated with MRI-detected infarcts after adjusting for sex and age. All non-SCA controls and SCA participants lacking MRI-detected infarcts had low NfL levels. These data suggest potential utility of plasma-based NfL levels to identify children with SCA cerebrovascular injury. Replication and prospective studies are needed to confirm these novel findings and the clinical utility of NfL versus MRI imaging.

Unusual Distribution of Cerebral Venous Thrombosis in a Patient With Sickle Cell Disease: A Case Study

This study presents the case of a 29-year-old Bahraini woman with a known history of sickle cell disease who exhibited acute neurological symptoms. Advanced imaging, specifically CT and MRI, identified cerebral venous thrombosis (CVT). The patient was managed with fluid therapy and anticoagulation, and received a packed red blood cell transfusion, leading to a complete recovery. Notably, this case was marked by the patient's positive anti-double stranded DNA (anti-dsDNA) status, typically linked with systemic lupus erythematosus (SLE), adding a potential pro-coagulant factor. The occlusion pattern, particularly involving the internal cerebral veins, was unique compared to other reviewed CVT cases in patients with sickle cell disease. This case emphasizes the significance of early diagnosis and intervention in CVT, especially in patients with sickle cell disease and other predisposing factors.

Hematologic Disorders and the Nervous System

OBJECTIVE

This article discusses the epidemiology, diagnosis, treatment, and prevention of neurologic complications of red blood cell, platelet, and plasma cell disorders.

LATEST DEVELOPMENTS

Cerebrovascular complications can occur in patients with blood cell and platelet disorders. Treatment strategies to prevent stroke are available for patients with sickle cell disease, polycythemia vera, and essential thrombocythemia. A diagnosis of thrombotic thrombocytopenic purpura should be considered in patients with neurologic symptoms, hemolytic anemia, thrombocytopenia, mild renal insufficiency, and fever. Plasma cell disorders can be associated with peripheral neuropathy, and classification of the monoclonal protein type and neuropathy aid in diagnosis. Patients with POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, and skin changes) syndrome can present with arterial and venous neurologic events.

ESSENTIAL POINTS

This article discusses the neurologic complications of blood cell disorders and the most recent advances in prevention and treatment.

Advances in the Diagnosis and Treatment of Pediatric Arterial Ischemic Stroke

Though rare, stroke in infants and children is an important cause of mortality and chronic morbidity in the pediatric population. Neuroimaging advances and implementation of pediatric stroke care protocols have led to the ability to rapidly diagnose stroke and in many cases determine the stroke etiology. Though data on efficacy of hyperacute therapies, such as intravenous thrombolysis and mechanical thrombectomy, in pediatric stroke are limited, feasibility and safety data are mounting and support careful consideration of these treatments for childhood stroke. Recent therapeutic advances allow for targeted stroke prevention efforts in high-risk conditions, such as moyamoya, sickle cell disease, cardiac disease, and genetic disorders. Despite these exciting advances, important knowledge gaps persist, including optimal dosing and type of thrombolytic agents, inclusion criteria for mechanical thrombectomy, the role of immunomodulatory therapies for focal cerebral arteriopathy, optimal long-term antithrombotic strategies, the role of patent foramen ovale closure in pediatric stroke, and optimal rehabilitation strategies after stroke of the developing brain.

Robust high spatio-temporal line-scanning fMRI in humans at 7T using multi-echo readouts, denoising and prospective motion correction

BACKGROUND

Functional magnetic resonance imaging (fMRI), typically using blood oxygenation level-dependent (BOLD) contrast weighted imaging, allows the study of brain function with millimeter spatial resolution and temporal resolution of one to a few seconds. At a mesoscopic scale, neurons in the human brain are spatially organized in structures with dimensions of hundreds of micrometers, while they communicate at the millisecond timescale. For this reason, it is important to develop an fMRI method with simultaneous high spatial and temporal resolution. Line-scanning promises to reach this goal at the cost of volume coverage.

NEW METHOD

Here, we release a comprehensive update to human line-scanning fMRI. First, we investigated multi-echo line-scanning with five different protocols varying the number of echoes and readout bandwidth while keeping the TR constant. In these, we compared different echo combination approaches in terms of BOLD activation (sensitivity) and temporal signal-to-noise ratio. Second, we implemented an adaptation of NOise reduction with DIstribution Corrected principal component analysis (NORDIC) thermal noise removal for line-scanning fMRI data. Finally, we tested three image-based navigators for motion correction and investigated different ways of performing fMRI analysis on the timecourses which were influenced by the insertion of the navigators themselves.

RESULTS

The presented improvements are relatively straightforward to implement; multi-echo readout and NORDIC denoising together, significantly improve data quality in terms of tSNR and t-statistical values, while motion correction makes line-scanning fMRI more robust.

COMPARISON WITH EXISTING METHODS

Multi-echo acquisitions and denoising have previously been applied in 3D magnetic resonance imaging. Their combination and application to 1D line-scanning is novel. The current proposed method greatly outperforms the previous line-scanning acquisitions with single-echo acquisition, in terms of tSNR (4.0 for single-echo line-scanning and 36.2 for NORDIC-denoised multi-echo) and t-statistical values (3.8 for single-echo line-scanning and 25.1 for NORDIC-denoised multi-echo line-scanning).

CONCLUSIONS

Line-scanning fMRI was advanced compared to its previous implementation in order to improve sensitivity and reliability. The improved line-scanning acquisition could be used, in the future, for neuroscientific and clinical applications.

Internalizing Symptoms in Adolescents With Sickle Cell Disease

OBJECTIVE

Sickle cell disease (SCD) is a genetic blood disorder that may affect patients' mood and behavior. However, measuring the prevalence of internalizing symptoms (anxiety and depression) in patients with SCD has been elusive. We assessed internalizing symptoms in adolescents with SCD to evaluate prevalence and to test whether neurocognitive performance and frequency of pain-related episodes were associated with internalizing concerns.

METHODS

One hundred eighty-five patients (57% HbSS/HbSß0-thalassemia, 43% HbSC/HbSß+-thalassemia), ages 12-18 years, received a neuropsychological evaluation as a part of a larger cohort study. Internalizing symptoms were measured using the Behavior Assessment System for Children, Second or Third Edition. Scores on the depression and anxiety scales were compared to normative values using Wilcoxon signed rank test. Spearman correlations examined associations between neurocognitive performances and internalizing symptoms. Robust multivariable regression models measured associations between internalizing symptoms and age, sex, sickle genotype, total hemoglobin, fetal hemoglobin, socioeconomic status, and frequency of pain episodes.

RESULTS

Parent- and self-reported ratings of internalizing symptoms were not elevated compared to normative expectations. Overall, 1.8% and 6.3% of the sample displayed clinically elevated symptoms of anxiety and depression based on self-report, respectively. There were no associations between internalizing symptoms and neurocognitive performance (all p > .05). In multivariable analyses, the frequency of pain episodes was positively associated with self-reported anxiety (p = .006) and parent-reported depressive symptoms (p = .017).

CONCLUSIONS

Adolescents with SCD do not report elevated internalizing symptoms compared to normative expectations. Further research is needed to examine the trajectory of internalizing symptoms and the bidirectional relationship between pain and psychosocial functioning in SCD.

Assessment of transition readiness to predict health care utilization during transition to adult care in sickle cell disease

BACKGROUND

Transition-age patients with sickle cell disease (SCD) are at risk for poor outcomes associated with incomplete transition readiness and neurocognitive deficits. Study objectives were to: 1) test if a SCD-specific measure of self-management skills was associated with transition outcomes and 2) evaluate if caregiver-reported executive functioning was associated with self-management skills and transition outcomes among youth with SCD.

RESEARCH DESIGN AND METHODS

Youth/caregivers were selected from a longitudinal cohort study. Caregivers completed the Behavior Rating Inventory of Executive Function (BRIEF); caregivers and youth completed the Self-Management Skills Checklist (SMSC) at a median age of 16.8 ± 0.6 years. Non-parametric tests compared SMSC and transition outcomes. Regression assessed the incremental validity of SMSC in predicting transition outcomes.

RESULTS

In total, 95 participants (54% male, 55% severe genotype) completed the SMSC assessment. Most participants (87%) transferred to adult care within six months and 87% were retained for at least 12 months. BRIEF and caregiver-reported SMSC assessments were weakly, negatively correlated (ρ = -0.25, p = 0.0392) but were not significant in predicting transition outcomes (p > 0.05).

CONCLUSIONS

The SMSC and executive function did not predict adult care engagement. Development of readiness assessments that predict care engagement and reflect self-efficacy is important for monitoring transition-aged patients with SCD.

Gene Editing for Sickle Cell Disease and Transfusion Dependent Thalassemias- A cure within reach

Sickle cell disease (SCD) is associated with significant morbidity and shortened life expectancy. Similarly, patients with transfusion dependent beta thalassemia (TdT) require life-long transfusion therapy, chelation therapy and significant organ dysfunction. Allogeneic transplantation from a matched family donor provided the only curative option for patients with SCD and TdT. Unfortunately, less than 20% of patients have a fully matched related donor and results using unrelated donor transplant were associated with high rate of complications. Ex vivo gene therapy through globin gene addition has been investigated extensively and recent encouraging preliminary data resulted in regulatory approval in patients with TdT. Recent improvements in our understanding of the molecular pathways controlling erythropoiesis and globin switching from fetal hemoglobin to adult hemoglobin offer a new and exciting therapeutic options. Rapid and substantial advances in genome editing tools using CRISPR/Cas9, have raised the possibility of genetic editing and correction in patient derived hematopoietic stem and progenitor cells. We will review results of gene editing approach that can induce fetal hemoglobin production in patients with SCD and TdT.

Numb Chin Syndrome in Sickle Cell Disease: A Systematic Review and Recommendations for Investigation and Management

Numb chin syndrome (NCS) is a rare sensory neuropathy resulting from inferior alveolar or mental nerve injury. It manifests as hypoesthesia, paraesthesia, or, rarely, as pain in the chin and lower lip. Several case reports suggest that sickle cell disease (SCD) could be a cause of NCS. However, information about NCS is scarce in this population. Our objectives were to synthesize all the available literature relevant to NCS in SCD and to propose recommendations for diagnosis and management based on the best available evidence. A systematic review was performed on several databases to identify all relevant publications on NCS in adults and children with SCD. We identified 73 publications; fourteen reports met the inclusion/exclusion criteria. These described 33 unique patients. Most episodes of NCS occurred in the context of typical veno-occlusive crises that involved the mandibular area. Radiological signs of bone infarction were found on some imaging, but not all. Neuropathy management was mostly directed toward the underlying cause. Overall, these observations suggest that vaso-occlusion and bone infarction could be important pathophysiological mechanisms of NCS. However, depending on the individual context, we recommend a careful evaluation to rule out differential causes, including infections, local tumors, metastatic disease, and stroke.

Quantitative susceptibility mapping (QSM) and R2* of silent cerebral infarcts in sickle cell anemia

Silent cerebral infarction (SCI) is the most commonly reported radiological abnormality in patients with sickle cell anemia (SCA) and is associated with future clinical stroke risk. To date, there have been few histological and quantitative MRI studies of SCI and multiple radiological definitions exist. As a result, the tissue characteristics and composition of SCI remain elusive. The objective of this work was therefore to investigate the composition of segmented SCI lesions using quantitative MRI for R2 * and quantitative magnetic susceptibility mapping (QSM). 211 SCI lesions were segmented from 32 participants with SCA and 6 controls. SCI were segmented according to two definitions (FLAIR+/-T1w-based threshold) using a semi-automated pipeline. Magnetic susceptibility (χ) and R2 * maps were calculated from a multi-echo gradient echo sequence and mean SCI values were compared to an equivalent region of interest in normal appearing white matter (NAWM). SCI χ and R2 * were investigated as a function of SCI definition, patient demographics, anatomical location, and cognition. Compared to NAWM, SCI were significantly less diamagnetic (χ = -0.0067 ppm vs. -0.0153 ppm, p < 0.001) and had significantly lower R2 * (16.7 s-1 vs. 19.2 s-1, p < 0.001). SCI definition had a significant effect on the mean SCI χ and R2 * , with lesions becoming significantly less diamagnetic and having significantly lower R2 * after the application of a more stringent T1w-based threshold. SCI-NAWM R2 * decrease was significantly greater in patients with SCA compared with controls (-2.84 s-1 vs. -0.64 s-1, p < 0.0001). No significant association was observed between mean SCI-NAWM χ or R2* differences and subject age, lesion anatomical location, or cognition. The increased χ and decreased R2 * in SCI relative to NAWM observed in both patients and controls is indicative of lower myelin or increased water content within the segmented lesions. The significant SCI-NAWM R2 * differences observed between SCI in patients with SCA and controls suggests there may be differences in tissue composition relative to NAWM in SCI in the two populations. Quantitative MRI techniques such as QSM and R2 * mapping can be used to enhance our understanding of the pathophysiology and composition of SCI in patients with SCA as well as controls.

The association between sleep disturbances and neurocognitive function in pediatric sickle cell disease

BACKGROUND AND OBJECTIVE

Youth with sickle cell disease (SCD) without neurological complications continue to be at increased risk of neurocognitive difficulties. Nocturnal hypoxemia is associated with neurocognitive outcomes and has been identified as a chronic complication in youth with SCD. The objective of this study was to assess the relationship between sleep disturbances and neurocognitive functioning in youth with SCD, while taking into account demographic and socioeconomic factors.

METHODS

Youth with SCD were identified through retrospective chart review who underwent a standardized polysomnography (PSG) and completed a neuropsychological testing battery to assess cognitive skills, including verbal comprehension, working memory, processing speed, and cognitive flexibility. Questionnaires were also collected to assess parent-reported concerns with their youth's executive and adaptive skills.

RESULTS

Twenty-seven youth with SCD, ages 6-17, were identified who completed both a PSG and neuropsychological testing. Results demonstrated that verbal comprehension decreased by 2.37 standard points for every unit decrease in mean nocturnal oxygen saturation (SpO2) (p = 0.031). Working memory was also found to decrease by 1.46 standard points for each 1% increase in time spent under 90% oxygen saturation (pTST SpO2 < 90%) (p = 0.030). Sleep parameters did not significantly predict other cognitive scores or parent-reported executive or behavioral ratings.

CONCLUSION

Our study found that sleep disturbance, mean nocturnal SpO2 and pTST SpO2 < 90%, significantly affected verbal comprehension and working memory performance, respectively. Overall, these findings have the potential to identify sleep needs in youth with SCD to promote sleep-targeted interventions as a modifiable factor to reduce neurocognitive deficits.

A Comparison of MRI Quantitative Susceptibility Mapping and TRUST-Based Measures of Brain Venous Oxygen Saturation in Sickle Cell Anaemia

In recent years, interest has grown in the potential for magnetic resonance imaging (MRI) measures of venous oxygen saturation (Yv) to improve neurological risk prediction. T2-relaxation-under-spin-tagging (TRUST) is an MRI technique which has revealed changes in Yv in patients with sickle cell anemia (SCA). However, prior studies comparing Yv in patients with SCA relative to healthy controls have reported opposing results depending on whether the calibration model, developed to convert blood T2 to Yv, is based on healthy human hemoglobin (HbA), bovine hemoglobin (HbBV) or sickle hemoglobin (HbS). MRI Quantitative Susceptibility Mapping (QSM) is an alternative technique that may hold promise for estimating Yv in SCA as blood magnetic susceptibility is linearly dependent upon Yv, and no significant difference has been found between the magnetic susceptibility of HbA and HbS. Therefore, the aim of this study was to compare estimates of Yv using QSM and TRUST with five published calibration models in healthy controls and patients with SCA. 17 patients with SCA and 13 healthy controls underwent MRI. Susceptibility maps were calculated from a multi-parametric mapping acquisition and Yv was calculated from the mean susceptibility in a region of interest in the superior sagittal sinus. TRUST estimates of T2, within a similar but much smaller region, were converted to Yv using five different calibration models. Correlation and Bland-Altman analyses were performed to compare estimates of Yv between TRUST and QSM methods. For each method, t-tests were also used to explore group-wise differences between patients with SCA and healthy controls. In healthy controls, significant correlations were observed between QSM and TRUST measures of Yv, while in SCA, there were no such correlations. The magnitude and direction of group-wise differences in Yv varied with method. The TRUST-HbBV and QSM methods suggested decreased Yv in SCA relative to healthy controls, while the TRUST-HbS (p < 0.01) and TRUST-HbA models suggested increased Yv in SCA as in previous studies. Further validation of all MRI measures of Yv, relative to ground truth measures such as O15 PET and jugular vein catheterization, is required in SCA before QSM or TRUST methods can be considered for neurological risk prediction.

Sickle cell cerebrovascular reactivity to a CO2 stimulus: Too little, too slow

Background: Despite increased cerebral blood flow (CBF), cerebral infarcts occur in patients with sickle cell disease (SCD). This suggests increased CBF does not meet metabolic demand possibly due to compromised cerebral vasodilatory response. Hypothesis: In adult SCD patients, cerebrovascular reactivity (CVR) and speed of vasodilatory response (tau) to a standardized vasodilatory stimulus, are reduced compared to normal subjects.

Methods: Functional brain imaging performed as part of routine care in adult SCD patients without known large vessel cerebral vasculopathy was reviewed retrospectively. CVR was calculated as the change in CBF measured as the blood-oxygenation-level-dependent (BOLD)-magnetic resonance imaging signal, in response to a standard vasoactive stimulus of carbon dioxide (CO₂). The tau corresponding to the best fit between the convolved end-tidal partial pressures of CO₂ and BOLD signal was defined as the speed of vascular response. CVR and tau were normalized using a previously generated atlas of 42 healthy controls.

Results: Fifteen patients were included. CVR was reduced in grey and white matter (mean Z-score for CVR −0.5 [−1.8 to 0.3] and −0.6 [−2.3 to 0.7], respectively). Tau Z-scores were lengthened in grey and white matter (+0.9 [−0.5 to 3.3] and +0.8 [−0.7 to 2.7], respectively). Hematocrit was the only significant independent predictor of CVR on multivariable regression.

Conclusion: Both measures of cerebrovascular health (CVR and tau) in SCD patients were attenuated compared to normal controls. These findings show that CVR represents a promising tool to assess disease state, stroke risk, and therapeutic efficacy of treatments in SCD and merits further investigation.

Reduction in seroprevalence of viral transfusion-transmitted infections in southwest Nigeria in children with sickle cell disease using an enhanced screening strategy

Blood transfusion is an integral component in the management of children and adults with sickle cell disease (SCD). Concerns about blood safety due to the high risk of bloodborne infections in sub-Saharan Africa limits the application of this cost-effective strategy in the management of individuals with SCD. In a single-centre, retrospective, longitudinal study in southwest Nigeria, we hypothesised that the use of stringent blood donor selection, along with very sensitive enzyme-linked immunosorbent assay (ELISA) screening methods would reduce transfusion-transmitted infections (TTIs). Among 45 002 eligible blood donors at the Lagos University Teaching Hospital in Nigeria, over a 5-year review period (2015-2019), the seroprevalence rate of viral TTIs was 9.83%. The seroprevalence rates for human immunodeficiency, hepatitis B, and hepatitis C viruses were 1.37%, 6.2%, and 2.25% respectively. Among 172 children with SCD, 71% (122/172) on regular blood transfusion and 29% (50/172) who had never been transfused or had less than two transfusions per lifetime, none acquired any TTIs using our enhanced screening approach during the study period. Thus, safe blood transfusion practices can be provided for children with SCD in sub-Saharan Africa with the use of stringent donor selection protocols and fourth-generation ELISA kits for TTI screening.

Dilemma in approach to stroke in sickle cell disease patient: A case report

INTRODUCTION

Cerebrovascular accidents in sickle cell disease (SCD) patients carry a high socioeconomic impact and represent the most important cause of morbidity, neurological deficits, and impaired quality of life in SCD young population.Patent foramen ovale (PFO) is prevalent in 25% of the general population and it is associated with ischemic stroke in the young population via paradoxical embolism, yet there are no specific guidelines to address how to manage SCD patients with PFO who suffer a stroke.

PATIENT CONCERNS AND DIAGNOSIS

Here we present a young SCD patient, aged 24 years, who suffered a stroke in childhood and later was discovered to have a PFO on subsequent echocardiography. The patient has been receiving blood transfusion therapy since 3 years of age.

INTERVENTIONS AND OUTCOMES

No treatment was administered to the patient.The intervention that was done was echocardiography with a bubble study to detect PFO.

CONCLUSION

Recommendations need to be put in place regarding screening for PFO in patients with SCD, in addition to highlighting issues of whether screening needs to be done in patients who have not developed stroke, and if PFO were to be found, what would be the best management approach and how will prognosis be affected.

Determinants of severity in sickle cell disease

Sickle cell disease is a very variable condition, with outcomes ranging from death in childhood to living relatively symptom free into the 8^th decade. Much of this variability is unexplained. The co-inheritance of α thalassaemia and factors determining HbF levels significantly modify the phenotype, but few other significant genetic variants have been identified, despite extensive studies. Environmental factors are undoubtedly important, with socio-economics and access to basic medical care explaining the huge differences in outcomes between many low- and high-income countries. Exposure to cold and windy weather seems to precipitate acute complications in many people, although these effects are unpredictable and vary with geography. Many studies have tried to identify prognostic factors which can be used to predict outcomes, particularly when applied in infancy. Overall, low haemoglobin, low haemoglobin F percentage and high reticulocytes in childhood are associated with worse outcomes, although again these effects are fairly weak and inconsistent.

Stroke in sickle cell disease in association with bilateral absence of the internal carotid arteries. Case report

Background

Congenital absence of the internal carotid artery (ICA) is a highly infrequent congenital incidence and occurs in less than 0.01% of the population; bilateral absence is exceedingly rare, diagnosed below 10% of the unilateral absence of the ICA. Sickle cell disease (SCD) is a serious disorder and carries a high risk of stroke.

Case presentation

We present a five-year-old child with SCD who experienced an ischemic stroke episode with epileptic seizures. Neuroimaging revealed the agenesis of both ICAs. The frequency, embryology, and collateral pathway of the vascular anomaly as the clinical presentation, of this rare hematologic disease, are discussed.

Conclusions

Sickle cell disease (SCD) carries a high risk of stroke. Congenital absence of ICA occurs in less than 0.01% of the population; bilateral absence is diagnosed below 10% of the unilateral absence of the ICA.

Assessment of functional shunting in patients with sickle cell disease

Silent cerebral infarcts (SCI) are common in patients with sickle cell disease (SCD) and are thought to be caused by a mismatch between oxygen delivery and consumption. Functional cerebrovascular shunting is defined as reduced oxygen offloading due to the rapid transit of blood through the capillaries caused by increased flow and has been suggested as a potential mechanism underlying reduced oxygenation and SCI. We investigated the venous arterial spin labeling signal (VS) in the sagittal sinus as a proxy biomarker of cerebral functional shunting, and its association with hemodynamic imaging and hematological laboratory parameters. We included 28 children and 38 adults with SCD, and ten healthy racematched adult controls. VS, cerebral blood flow (CBF), velocity in the brain feeding arteries, oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) were measured before and after acetazolamide administration. VS was higher in patients with SCD compared to controls (P<0.01) and was increased after acetazolamide administration in all groups (P<0.01). VS was primarily predicted by CBF (P<0.01), but CBF-corrected VS was also associated with decreased CMRO2 (P<0.01). Additionally, higher disease severity defined by low hemoglobin and increased hemolysis was associated with higher CBF-corrected VS. Finally, CMRO2 was negatively correlated with fetal hemoglobin, and positively correlated with lactate dehydrogenase, which could be explained by changes in oxygen affinity. These findings provide evidence for cerebral functional shunting and encourage future studies investigating the potential link to aberrant capillary exchange in SCD.

Reproducibility of cerebrovascular reactivity measurements: A systematic review of neuroimaging techniques. J Cereb Blood Flow Metab 2022;42:700-717. [PMID: 34806918 PMCID: PMC9254040 DOI: 10.1177/0271678x211056702]

Cerebrovascular reactivity (CVR), the capacity of the brain to increase cerebral blood flow (CBF) to meet changes in physiological demand, is an important biomarker to evaluate brain health. Typically, this brain "stress test" is performed by using a medical imaging modality to measure the CBF change between two states: at baseline and after vasodilation. However, since there are many imaging modalities and many ways to augment CBF, a wide range of CVR values have been reported. An understanding of CVR reproducibility is critical to determine the most reliable methods to measure CVR as a clinical biomarker. This review focuses on CVR reproducibility studies using neuroimaging techniques in 32 articles comprising 427 total subjects. The literature search was performed in PubMed, Embase, and Scopus. The review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We identified 5 factors of the experimental subjects (such as sex, blood characteristics, and smoking) and 9 factors of the measuring technique (such as the imaging modality, the type of the vasodilator, and the quantification method) that have strong effects on CVR reproducibility. Based on this review, we recommend several best practices to improve the reproducibility of CVR quantification in neuroimaging studies.

Spontaneous Epidural Hematoma in Sickle Cell Crisis: A Case Report

Epidural hematoma (EDH) classically occurs secondary to trauma. Spontaneous EDH is uncommon and can be a rare complication of sickle cell disease (SCD). We report the case of a 20-year-old Indian male with sickle cell anemia, who presented with a sickling bony crisis and suffered a non-traumatic EDH within 24 hours of admission.

A 20-year-old male presented with generalized body pain, suggestive of a sickling bony crisis. He was promptly admitted and received standard treatment for the same. The next day, he developed severe right-sided headache, associated with orbital pain, decreased movements on the right side, and altered sensorium. He had a Glasgow coma scale score of 8/15, and reduced power of the right upper limb and lower limb. Computed tomography (CT) and magnetic resonance imaging (MRI) of the brain showed a left-sided large parieto-temporal epidural hematoma with midline shift and mass effect. He underwent emergency decompressive craniotomy and evacuation of the hematoma, following which he recovered well, with no residual deficits.

Spontaneous EDH is being increasingly reported in SCD. Possible mechanisms include skull bone infarction, altered skull bone anatomy due to extramedullary hematopoiesis, and venous congestion due to sluggish blood flow in diploic veins. In our patient, altered skull anatomy appeared to be the causative mechanism. Early identification of EDH and aggressive neurosurgical management is crucial to survival and a good prognosis.

Burden of central nervous system complications in sickle cell disease: A systematic review and meta-analysis

Sickle cell disease (SCD) patients are at high risk of central nervous system (CNS) complications and may experience significant morbidity. The study was conducted to describe the comprehensive burden of SCD-related CNS complications and to identify patient-reported outcome (PRO) instruments for future research. The review included 32 studies published from January 2000 to 2020, evaluating humanistic and economic outcomes. Twenty-three studies reported humanistic outcomes, 16 of which measured cognitive function using Wechsler Intelligence Scales. A meta-analysis was conducted, finding full-scale intelligence quotient (IQ) was significantly lower in: overt stroke versus controls: -12.6 (p < .001); silent cerebral infarct (SCI) versus controls: -5.7 (p < .001); overt stroke versus SCI: -9.4 (p = .008); and any event versus controls: -7.6 (p < .001). This review quantified the cognitive deficits associated with CNS complications in pediatric SCD populations and highlights the need for improved prevention/treatment. As PRO evidence was limited, we discussed areas for future research.

Brain Magnetic Resonance Imaging and Angiography in Children with Sickle Cell Anaemia in Uganda in a Cross-Sectional Sample

OBJECTIVE

Children with sickle cell anaemia (SCA) are highly susceptible to cerebrovascular injury. We performed brain magnetic resonance imaging and angiography (MRI-MRA) in Ugandan children with SCA to identify structural cerebrovascular abnormalities and examine their relationship to standardized clinical assessments.

METHODS

A sub-sample (n=81) was selected from a cross-sectional study of children attending SCA clinic, including 52 (64.2%) with and 29 (35.8%) without clinically detected abnormalities. Clinical evaluation included assessment for prior stroke, cognitive testing and cerebral arterial transcranial doppler (TCD) flow velocity. MRI-MRA scans were interpreted by at least two neuroradiologists.

RESULTS

Mean age was 6.5±2.7 years, with 39 (48.1%) female. Mean haemoglobin was 7.3±0.9 g/dl. Overall, 13 (16.0%) were malnourished. Infarcts and/or stenoses were detected in 55 (67.9%) participants, with stenoses primarily in the anterior circulation. Infarcts were seen in those with normal 17/29 (58.6%) or abnormal 34/52 (65.4%) clinical testing (p=0.181). Neither abnormal MRI nor MRA was associated with age, sex, haemoglobin, or malnutrition. Abnormal MRA was highly associated with infarcts (p<0.0001). Participants with abnormal imaging had two-fold higher proportion of stroke on exam and/or impaired cognition. Stroke on exam was strongly associated with an imaging abnormality after adjusting for age, sex, malnutrition, and haemoglobin (OR 11.8, 95%CI 1.87-74.2).

CONCLUSION

Over half of these SCA children had cerebrovascular infarcts and/or arterial stenoses. Cerebrovascular disease was frequently undetectable by clinical assessments. While rarely available in under-resourced settings, MRI-MRA brain imaging is an important tool for defining SCA cerebrovascular disease and for assessing impact of clinical intervention trials.

Hydroxyurea for primary stroke prevention in children with sickle cell anaemia in Nigeria (SPRING): a double-blind, multicentre, randomised, phase 3 trial

BACKGROUND

In high-income countries, standard care for primary stroke prevention in children with sickle cell anaemia and abnormal transcranial Doppler velocities results in a 92% relative risk reduction of strokes but mandates initial monthly blood transfusion. In Africa, where regular blood transfusion is not feasible for most children, we tested the hypothesis that initial moderate-dose compared with low-dose hydroxyurea decreases the incidence of strokes for children with abnormal transcranial Doppler velocities.

METHODS

SPRING is a double-blind, parallel-group, randomised, controlled, phase 3 trial of children aged 5-12 years with sickle cell anaemia with abnormal transcranial Doppler velocities conducted at three teaching hospitals in Nigeria. For randomisation, we used a permuted block allocation scheme with block sizes of four, stratified by sex and site. Allocation was concealed from all but the pharmacists and statisticians. Participants were assigned in a 1:1 ratio to low-dose (10 mg/kg per day) or moderate-dose (20 mg/kg per day) oral hydroxyurea taken once daily with monthly clinical evaluation and laboratory monitoring. The primary outcome was initial stroke or transient ischaemic attack, centrally adjudicated. The secondary outcome was all-cause hospitalisation. We used the intention-to-treat population for data analysis. The trial was stopped early for futility after a planned minimum follow-up of 3·0 years to follow-up for participants. This trial was registered with ClinicalTrials.gov, number NCT02560935.

FINDINGS

Between Aug 2, 2016, and June 14, 2018, 220 participants (median age 7·2 years [IQR 5·5-8·9]; 114 [52%] female) were randomly allocated and followed for a median of 2·4 years (IQR 2·0-2·8). All participants were Nigerian and were from the following ethnic groups: 179 (82%) people were Hausa, 25 (11%) were Fulani, and 16 (7%) identified as another ethnicity. In the low-dose hydroxyurea group, three (3%) of 109 participants had strokes, with an incidence rate of 1·19 per 100 person-years and in the moderate-dose hydroxyurea group five (5%) of 111 had strokes with an incidence rate of 1·92 per 100 person-years (incidence rate ratio 0·62 [95% CI 0·10-3·20], p=0·77). The incidence rate ratio of hospitalisation for any reason was 1·71 (95% CI 1·15-2·57, p=0·0071), with higher incidence rates per 100 person-years in the low-dose group versus the moderate-dose group (27·43 vs 16·08). No participant had hydroxyurea treatment stopped for myelosuppression.

INTERPRETATION

Compared with low-dose hydroxyurea therapy, participants treated with moderate-dose hydroxyurea had no difference in the stroke incidence rate. However, secondary analyses suggest that the moderate-dose group could lower incidence rates for all-cause hospitalisations. These findings provide an evidence-based guideline for the use of low-dose hydroxyurea therapy for children with sickle cell anaemia at risk of stroke.

FUNDING

National Institute of Neurological Disorders and Stroke.

Catastrophic Neurological Complications in 2 Patients With Sickle Cell Disease and COVID-19

Severe acute respiratory syndrome coronavirus (SARS-CoV-2) infection is commonly associated with neurological complications. Patients with sickle cell disease are at increased risk of developing neurologic complications throughout their lifetimes and often have underlying cardiopulmonary comorbidities that may predispose them to poor outcomes during serious infections. In this case series, we describe 2 patients with sickle cell disease who developed devastating neurologic complications following SARS-CoV-2 infection, which ultimately led to brain edema and death. We highlight the unusual manifestations of coronavirus disease 2019 in patients with sickle cell disease and address the risk of these patients to develop catastrophic neurologic injury due to COVID-19, if not recognized promptly.

A case series of hemorrhagic neurological complications of sickle cell disease: Multiple faces of an underestimated problem!

Sickle cell disease (SCD) is a group of hemoglobinopathies that vary in severity, the most severe form, homozygous sickle cell anemia, is more commonly associated with neurologic complications. These are attributed to the vaso-occlusion and micro-obstruction in the circulation of the central nervous system. The incidence of various neurologic complications in SCD ranges from 6% to 30% in various series. The commonly reported in literature include silent cerebral infarction (SCI), ischemic stroke, transient ischemic attacks (TIAs), headaches, seizures and neurocognitive impairment. However, hemorrhagic complications like subarachnoid hemorrhage (SAH), hemorrhagic stroke, extradural and subdural hematomas, especially in absence of trauma are rarely thought of. We report three uncommon spontaneous hemorrhagic manifestations of sickle cell anemia – one case of parenchymal (intracerebral) bleed who presented with acute onset of parkinsonism and two cases of extradural hematoma (EDH) of which one patient had recurrent EDH at the same site which is hitherto not reported in the literature.

Changes in Care Delivery for Children With Sickle Cell Anemia During the COVID-19 Pandemic

BACKGROUND

Specialty care for children with sickle cell disease (SCD) may be disrupted during the coronavirus (COVID-19) pandemic. Our DISPLACE consortium includes 28 pediatric SCD centers.

METHODS

In May 2020, we surveyed the consortium on the impact of COVID-19 on their practice focusing on transcranial Doppler ultrasound, chronic red cell transfusions, telehealth, and COVID-19 testing.

OBSERVATION

Twenty-four DISPLACE providers completed the survey. Transcranial Doppler ultrasound screening decreased to 67% but chronic red cell transfusions remained at 96%. Most investigators (92%) used telehealth and 40% of providers had patients test positive for COVID-19.

CONCLUSION

The COVID-19 pandemic has affected routine care and necessitated changes in practice in SCD.

Hematopoietic stem cell transplantation reverses white matter injury measured by diffusion-tensor imaging (DTI) in sickle cell disease patients

Brain injury in sickle cell disease (SCD) comprises a wide spectrum of neurological damage. Neurocognitive deficits have been described even without established neurological lesions. DTI is a rapid, noninvasive, and non-contrast method that enables detection of normal-appearing white matter lesions not detected by conventional magnetic resonance imaging (MRI). The aim of the study was to evaluate if stem cell transplantation can revert white matter lesions in patients with SCD. Twenty-eight SCD patients were evaluated with MRI and DTI before and after allogeneic hematopoietic stem cell transplantation (HSCT), compared with 26 healthy controls (HC). DTI metrics included fractional anisotropy (FA), mean diffusivity (MD), radial (RD), and axial (AD) diffusivity maps, global efficiency, path length, and clustering coefficients. Compared to HC, SCD patients had a lower FA (p = 0.0086) before HSCT. After HSCT, FA increased and was not different from healthy controls (p = 0.1769). Mean MD, RD, and AD decreased after HSCT (p = 0.0049; p = 0.0029; p = 0.0408, respectively). We confirm previous data of white matter lesions in SCD and present evidence that HSCT promotes recovery of brain injury with potential improvement of brain structural connectivity.

Study of montelukast in children with sickle cell disease (SMILES): a study protocol for a randomised controlled trial

Background

Young children with sickle cell anaemia (SCA) often have slowed processing speed associated with reduced brain white matter integrity, low oxygen saturation, and sleep-disordered breathing (SDB), related in part to enlarged adenoids and tonsils. Common treatments for SDB include adenotonsillectomy and nocturnal continuous positive airway pressure (CPAP), but adenotonsillectomy is an invasive surgical procedure, and CPAP is rarely well-tolerated. Further, there is no current consensus on the ability of these treatments to improve cognitive function. Several double-blind, randomised controlled trials (RCTs) have demonstrated the efficacy of montelukast, a safe, well-tolerated anti-inflammatory agent, as a treatment for airway obstruction and reducing adenoid size for children who do not have SCA. However, we do not yet know whether montelukast reduces adenoid size and improves cognition function in young children with SCA.

Methods

The Study of Montelukast In Children with Sickle Cell Disease (SMILES) is a 12-week multicentre, double-blind, RCT. SMILES aims to recruit 200 paediatric patients with SCA and SDB aged 3–7.99 years to assess the extent to which montelukast can improve cognitive function (i.e. processing speed) and sleep and reduce adenoidal size and white matter damage compared to placebo. Patients will be randomised to either montelukast or placebo for 12 weeks. The primary objective of the SMILES trial is to assess the effect of montelukast on processing speed in young children with SCA. At baseline and post-treatment, we will administer a cognitive evaluation; caregivers will complete questionnaires (e.g. sleep, pain) and measures of demographics. Laboratory values will be obtained from medical records collected as part of standard care. If a family agrees, patients will undergo brain MRIs for adenoid size and other structural and haemodynamic quantitative measures at baseline and post-treatment, and we will obtain overnight oximetry.

Discussion

Findings from this study will increase our understanding of whether montelukast is an effective treatment for young children with SCA. Using cognitive testing and MRI, the SMILES trial hopes to gain critical knowledge to help develop targeted interventions to improve the outcomes of young children with SCA.

Trial registration

ClinicalTrials.govNCT04351698. Registered on April 17, 2020. European Clinical Trials Database (EudraCT No. 2017-004539-36). Registered on May 19, 2020

Biopsychosocial Predictors of Quality of Life in Paediatric Patients With Sickle Cell Disease

Sickle cell disease (SCD) refers to a group of inherited blood disorders with considerable morbidity that causes severe pain, reduces life expectancy, and requires significant self-management. Acute painful episodes are the hallmark of SCD, but persistent daily pain is also highly prevalent in this population. Characterising the impact and experience of SCD-related morbidity (i.e., sleep disruption, frequent emergency department visits, cognitive dysfunction) on health-related quality of life (HRQOL) requires multiple assessment methods to best capture the underlying mechanisms. To gain a greater understanding of the effect of common symptom categories on HRQOL and to determine potential pain coping targets, the present study investigated whether demographic, socioeconomic, sleepiness, pain burden, frequency of emergency department (ED) visits, and cognition predicted HRQOL in a paediatric sample of patients with SCD. Our study was a secondary analysis of baseline assessment data of children with SCD aged 8-15 years (n = 30) in the Prevention of Morbidity in Sickle Cell Anaemia Phase 2b (POMSb2) randomised controlled clinical trial of auto-adjusting continuous positive airways pressure. Patients completed cognitive testing (IQ, Processing Speed Index, Delis-Kaplan Executive Function Scale (DKEFS) Tower, Conner's Continuous Performance Test), sleepiness (Epworth Sleepiness Scale), and HRQOL (PedsQL Sickle Cell Module) at baseline. Patients reported pain burden (Sickle Cell Pain Burden Inventory-Youth) each month over 8 visits. Caregivers provided demographic information and reported their child's executive function (Behavioural Rating Inventory of Executive Function) at baseline. Data from our analysis demonstrated that demographic factors (i.e., age, gender, level of neighbourhood deprivation) and treatment variables (i.e., hydroxyurea use) did not independently predict HRQOL, and laboratory values (i.e., haemoglobin, haematocrit, mean oxygen saturation) were not significantly correlated with HRQOL (ps > 0.05). However, sleepiness, pain burden, ED visits, and executive dysfunction independently predicted HRQOL (R ² = 0.66) with large effects (η² = 0.16 to 0.32). These findings identify specific, measurable symptom categories that may serve as targets to improve HRQOL that are responsive to change. This knowledge will be useful for multimodal interventions for paediatric patients with SCD that include sleep management, pain coping strategies, and executive function training.