Intracranial Aneurysms in Sickle Cell Disease

Development of multiple intracranial aneurysms: beyond the common risk factors

OBJECTIVE

The prevalence of multiple intracranial aneurysms (MIAs) has increased over the last decades. Because MIAs have been identified as an independent risk factor for formation, growth, and rupture of intracranial aneurysms (IAs), a more profound understanding of the underlying pathophysiology of MIAs is needed. Therefore, the authors' extensive institutional aneurysm database was analyzed to elucidate differences between patients with a single IA (SIA) and those with MIAs.

METHODS

A total of 2446 patients seen with or for IAs at the University Hospital of Essen, Essen, Germany, from January 2003 to June 2016 were included in this retrospective cohort study and were separated into MIA and SIA subgroups. Patient data were screened for sociodemographic and radiographic parameters, preexisting medical conditions, and results of blood examinations. These parameters were analyzed for their correlations with MIAs and absolute number of IAs.

RESULTS

MIAs were identified in 853 (34.9%) patients. In multivariable analysis, MIAs were independently associated with female sex (p = 0.001), arterial hypertension (p = 0.023), tobacco abuse (p = 0.009), AB blood group (p = 0.010), and increased admission values for C-reactive protein (p = 0.006), mean corpuscular volume (p = 0.009), and total serum protein (p = 0.034), but not with diagnostic modality (3D vs 2D digital subtraction angiography, p = 0.912). Absolute number of IAs was independently associated with female sex (p < 0.001), arterial hypertension (p = 0.014), familial predisposition to IA (p = 0.015), tobacco consumption (p = 0.025), increased mean corpuscular volume (p = 0.002), and high platelet count (p = 0.007).

CONCLUSIONS

In this sizable consecutive series of patients with IAs, the authors confirmed the impact of common IA risk factors on the genesis of MIAs. In addition, specific hemorheological and hemocytological features may also contribute to the development of MIAs.

A New Subform? Fast-Progressing, Severe Neurological Deterioration Caused by Spinal Epidural Lipomatosis

Spinal epidural lipomatosis (SEL) is a rare condition caused by hypertrophic growth of epidural fat. The prevalence of SEL in the Western world is approximately 1 in 40 patients and is likely to increase due to current medical and socio-economic developments. Rarely, SEL can lead to rapid severe neurological deterioration. The pathophysiology, optimal treatment, and outcome of these patients remain unclear. This study aims to widen current knowledge about this “SEL subform” and to improve its clinical management. A systematic literature review according to the PRISMA guidelines using PubMed, Scopus, Web of Science, and Cochrane Library was used to identify publications before 7 November 2021 reporting on acute/rapidly progressing, severe SEL. The final analysis comprised 12 patients with acute, severe SEL. The majority of the patients were male (9/12) and multimorbid (10/12). SEL mainly affected the thoracic part of the spinal cord (11/12), extending a median number of 7 spinal levels (range: 4–19). Surgery was the only chosen therapy (11/12), except for one critically ill patient. Regarding the outcome, half of the patients regained independence (6/11; = modified McCormick Scale ≤ II). Acute, severe SEL is a rare condition, mainly affecting multimorbid patients. The prognosis is poor in nearly 50% of the patients, even with maximum therapy. Further research is needed to stratify patients for conservative or surgical treatment.

Stroke and stroke prevention in sickle cell anemia in developed and selected developing countries

This comprehensive review provides an insight into the pathophysiology, epidemiology, evaluation, and treatment of sickle cell anemia (SCA)-related stroke in developed and developing countries. Vascular injury, hypercoagulability and vaso-occlusion play a role in the pathophysiology of stroke in SCA. Transcranial Doppler ultrasound (TCD) has lowered the incidence of ischemic stroke from 11% to 1% as TCD identifies children who are at risk for stroke, providing opportunities for interventions to reduce this risk. Whereas blood exchange is indicated in acute stroke, chronic transfusions (either simple or exchange on a monthly basis) are used for primary as well as secondary stroke prevention in developed countries. Children with abnormally high TCD velocities (≥ 200 cm/s) are at high risk of stroke and might benefit from hydroxyurea or hydroxycarbamide (HU) after a period of a successful transition from chronic transfusions. Hematopoietic stem cell transplant presents a cure for SCA. Gene therapy is currently investigated and may be offered to patients with SCA who had a stroke or who are at high risk of stroke if proven efficacious and safe. However, gene therapy is not likely to be implemented in low-income countries due to cost. Alternatively, HU is utilized for primary and secondary stroke prevention in developing countries. Further expansion of TCD implementation should be a priority in those settings.

American Society of Hematology 2020 guidelines for sickle cell disease: prevention, diagnosis, and treatment of cerebrovascular disease in children and adults

BACKGROUND

Central nervous system (CNS) complications are among the most common, devastating sequelae of sickle cell disease (SCD) occurring throughout the lifespan.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology are intended to support the SCD community in decisions about prevention, diagnosis, and treatment of the most common neurological morbidities in SCD.

METHODS

The Mayo Evidence-Based Practice Research Program supported the guideline development process, including updating or performing systematic evidence reviews. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including GRADE evidence-to-decision frameworks, to assess evidence and make recommendations.

RESULTS

The panel placed a higher value on maintaining cognitive function than on being alive with significantly less than baseline cognitive function. The panel developed 19 recommendations with evidence-based strategies to prevent, diagnose, and treat CNS complications of SCD in low-middle- and high-income settings.

CONCLUSIONS

Three of 19 recommendations immediately impact clinical care. These recommendations include: use of transcranial Doppler ultrasound screening and hydroxyurea for primary stroke prevention in children with hemoglobin SS (HbSS) and hemoglobin Sβ0 (HbSβ0) thalassemia living in low-middle-income settings; surveillance for developmental delay, cognitive impairments, and neurodevelopmental disorders in children; and use of magnetic resonance imaging of the brain without sedation to detect silent cerebral infarcts at least once in early-school-age children and once in adults with HbSS or HbSβ0 thalassemia. Individuals with SCD, their family members, and clinicians should become aware of and implement these recommendations to reduce the burden of CNS complications in children and adults with SCD.

Vascular Instability and Neurological Morbidity in Sickle Cell Disease: An Integrative Framework

It is well-established that patients with sickle cell disease (SCD) are at substantial risk of neurological complications, including overt and silent stroke, microstructural injury, and cognitive difficulties. Yet the underlying mechanisms remain poorly understood, partly because findings have largely been considered in isolation. Here, we review mechanistic pathways for which there is accumulating evidence and propose an integrative systems-biology framework for understanding neurological risk. Drawing upon work from other vascular beds in SCD, as well as the wider stroke literature, we propose that macro-circulatory hyper-perfusion, regions of relative micro-circulatory hypo-perfusion, and an exhaustion of cerebral reserve mechanisms, together lead to a state of cerebral vascular instability. We suggest that in this state, tissue oxygen supply is fragile and easily perturbed by changes in clinical condition, with the potential for stroke and/or microstructural injury if metabolic demand exceeds tissue oxygenation. This framework brings together recent developments in the field, highlights outstanding questions, and offers a first step toward a linking pathophysiological explanation of neurological risk that may help inform future screening and treatment strategies.