Neuroimaging in childhood arterial ischaemic stroke: evaluation of imaging modalities and aetiologies

Why Would a Child Have a Stroke?

Identifying the etiology of childhood arterial ischemic stroke helps prevent stroke recurrence. In addition, stroke may herald a serious underlying condition requiring treatment, such as acquired heart disease, malignancy, or autoimmune disorder. Evidence-based guidelines exist for adults to identify and treat common risk factors for primary and secondary stroke, including hypertension, diabetes, elevated lipids, atrial fibrillation, and sleep apnea, which are rarely relevant in children. However, guidelines do not exist in pediatrics. Identifying the cause of childhood stroke may be straightforward or may require extensive clinical and neuroimaging expertise, serial evaluations, and reassessment based on the evolving clinical picture. Risk factors may be present but not necessarily causative, or not causative until a triggering event such as infection or anemia occurs. Herein, we describe strategies to determine stroke etiology, including challenges and potential pitfalls.

Posterior Arterial Ischemic Stroke in Childhood

Background and Purpose—

Literature on the clinical manifestation and neuroradiological findings in pediatric patients with posterior circulation arterial ischemic stroke is scarce. This study aims to describe epidemiological features, clinical characteristics, and neuroimaging data on pediatric posterior circulation arterial ischemic stroke in Switzerland using the population-based Swiss Neuropediatric Stroke Registry.

Methods—

Children aged from 1 month to 16 years presenting with an isolated posterior circulation arterial ischemic stroke between 2000 and 2016 were included. Epidemiology, clinical manifestation, stroke cause, and neuroradiological features were summarized using descriptive statistics. Stroke severity was assessed using the pediatric National Institutes of Health Stroke Scale. Correlation analysis was performed using the Spearman correlation coefficient.

Results—

Forty-three children with posterior circulation arterial ischemic stroke were included (27 boys [62.8%], median age 7.9 years, interquartile range, 5 to 11.7 years). The incidence of posterior circulation arterial ischemic stroke is Switzerland was 0.183/100 000 and represented 16% of all childhood arterial ischemic strokes. Most patients presented with nonspecific neurological complaints, such as headache (58.1%) and nausea/vomiting (46.5%). The most frequent clinical manifestations were ataxia (58.1%) and motor/sensory hemisyndrome (53.5%/51.2%). Unilateral focal cerebral arteriopathy was the most common cause (11 children, 25.6%). Most infarcts were located in the cerebellum (46.5%) and thalamus (39.5%). A shorter diagnostic delay correlated with more severe stroke symptoms at presentation (rho= −0.365, P =0.016).

Conclusions—

Pediatric posterior circulation arterial ischemic stroke was caused by focal cerebral arteriopathy in one quarter of the patients in our cohort. The frequently reported nonspecific clinical symptoms, especially when associated with mild neurological findings, risk delaying the diagnosis of stroke. A high index of suspicion and increased awareness are required for timely diagnosis and treatment initiation.

Association Between Prolonged Seizures and Malignant Middle Cerebral Artery Infarction in Children With Acute Ischemic Stroke

BACKGROUND

Malignant middle cerebral artery infarct syndrome is a potentially fatal complication of stroke that is poorly understood in children. We studied the frequency, associated characteristics, and outcomes of this condition in children.

METHODS

Children, aged two months to 18 years with acute middle cerebral artery infarct diagnosed at our center between January 2005 and December 2012 were studied. Associations with malignant middle cerebral artery infarct syndrome were sought, including age, seizures, neurological deficit severity (Pediatric National Institute of Health Stroke Severity Score), stroke etiology, fever, blood pressure, blood glucose, infarct location, infarct volume (modified pediatric Alberta Stroke Program Early Computed Tomography Score), and arterial occlusion. Death and neurological outcomes were determined.

RESULTS

Among 66 children with middle cerebral artery stroke, 12 (18%) developed malignant middle cerebral artery infarct syndrome, fatal in three. Prolonged seizures during the first 24 hours (odds ratio, 25.51; 95% confidence interval, 3.10 to 334.81; P = 0.005) and a higher Pediatric National Institute of Health Stroke Severity Score (odds ratio, 1.22; 95% confidence interval, 1.08 to 1.45; P = 0.006) were independently associated with malignant middle cerebral artery infarct syndrome. All children aged greater than two years with a Pediatric National Institute of Health Stroke Severity Score ≥8 and initial seizures ≥5 minutes duration developed malignant middle cerebral artery infarct syndrome (100%).

CONCLUSIONS

Malignant middle cerebral artery infarct syndrome affects nearly one in five children with acute middle cerebral artery stroke. Children with higher Pediatric National Institute of Health Stroke Severity Scores and prolonged initial seizures are at greatly increased risk for malignant middle cerebral artery infarct syndrome. Children with middle cerebral artery infarcts warrant intensive neuroprotective management and close monitoring to enable early referral for hemicraniectomy surgery.

Vascular disease

The child presenting with possible sentinel transient ischemic event or stroke requires prompt diagnosis so that strategies to limit injury and prevent recurrent stroke can be instituted. Cerebral arteriopathy is a potent risk factor for arterial ischemic stroke in childhood. Though acute imaging study in the setting of possible stroke is often a head computed tomography, when possible magnetic resonance imaging (MRI) is recommended as the first-line study as confirmation and imaging evaluation of ischemic stroke will typically require MRI. The MRI scanning approach should include diffusion-weighted imaging (DWI) early in the sequence order, since normal DWI excludes acute infarct with rare exception. In most cases, arterial imaging with time-of-flight (TOF) magnetic resonance angiography (MRA) is warranted. Dedicated MRA may not be possible in the acute setting, but should be pursued as promptly as possible, particularly in the child with findings and history suggestive of arteriopathy, given the high risk of recurrent stroke in these children. MRA can overestimate the degree of arterial compromise due to complex/turbulent flow, and be insensitive to subtle vessel irregularity due to resolution and complex flow. In cases with high imaging suspicion for dissection despite normal MRA findings, catheter angiogram is indicated. A thoughtful, stepwise approach to arterial neuroimaging is critical to optimize diagnosis, treatment, and primary and secondary prevention of childhood stroke.

Ischaemic stroke in children with cardiopathy: An epidemiological study

INTRODUCTION

Ischaemic stroke is rare during childhood. Congenital and acquired heart diseases are one of the most important risk factors for arterial ischaemic stroke (AIS) in children.

PATIENTS AND METHODS

We conducted a retrospective study of all children with AIS and heart disease diagnosed between 2000 and 2014.

RESULTS

We included 74 children with heart disease who were eligible for inclusion. 60% were boys with a mean stroke age of 11 months. 20% of the patients died during the study period. 90% of the patients had a congenital heart disease, while cyanotic heart disease was identified in 60%. Hypoplastic left heart syndrome was the most frequent heart disease. In 70% of patients AIS was directly associated with heart surgery, catheterisation or ventricular assist devices. Most patients with AIS were in the hospital. Seizures and motor deficit were the most frequent symptoms. Most patient diagnoses were confirmed by brain CT. The AIS consisted of multiple infarcts in 33% of the cases, affected both hemispheres in 27%, and involved the anterior and posterior cerebral circulation in 10%.

CONCLUSIONS

Arterial ischaemic strokes were mainly associated with complex congenital heart diseases, and heart procedures and surgery (catheterisation). AIS presented when patients were in-hospital and most of the patients were diagnosed in the first 24hours.

Hospitalização por acidente vascular encefálico isquêmico no Brasil: estudo ecológico sobre possível impacto do Hiperdia

RESUMO: Objetivo: O estudo avaliou a tendência de hospitalização por acidente vascular encefálico isquêmico (HAVEI) e a sua mortalidade hospitalar no Brasil nos últimos 15 anos, assim como o impacto do programa Hiperdia nesse cenário. Métodos: Delineou-se um estudo ecológico com abordagem analítica e dados coletados no Sistema de Internação Hospitalar sobre episódios de AVEI, referentes aos anos de 1998 a 2012. Todos os dados foram estratificados por sexo e faixa etária, criando-se um indicador para HAVEI e proporção de mortalidade hospitalar. A fim de estimar a tendência dos dados criou-se uma curva polinomial de melhor aderência e para a averiguar o impacto do Hiperdia aplicou-se o Modelo Linear Generalizado tomados como desfecho a HAVEI e a mortalidade hospitalar. Adotou-se um nível de significância de 5% para minimizar um erro tipo I. Resultados: Foi evidenciada redução das HAVEI de 37,57/105 habitantes em 1998 a 2001 para 10,33/105 habitantes em 2002 a 2005, declinando 73,64%. A redução aconteceu em ambos os sexos, assim como para todas as faixas etárias. A mortalidade hospitalar por AVEI também declinou no Brasil a partir de 2002, tanto em homens como em mulheres, porém em menos de 3% e apenas nas faixas entre 0 e 14 anos e acima de 80 anos não detectamos tendência. Conclusão: Portanto, o declínio das HAVEI coincidiu temporalmente com a implementação do Hiperdia no ano de 2002 e essa tendência se mantém até hoje.

Cortical reorganisation of cerebral networks after childhood stroke: impact on outcome

BACKGROUND

Recovery after arterial ischaemic stroke is known to largely depend on the plastic properties of the brain. The present study examines changes in the network topography of the developing brain after stroke. Effects of brain damage are best assessed by examining entire networks rather than single sites of structural lesions. Relating these changes to post-stroke neuropsychological variables and motor abilities will improve understanding of functional plasticity after stroke. Inclusion of healthy controls will provide additional insight into children's normal brain development. Resting state functional magnetic resonance imaging is a valid approach to topographically investigate the reorganisation of functional networks after a brain lesion. Transcranial magnetic stimulation provides complementary output information. This study will investigate functional reorganisation after paediatric arterial ischaemic stroke by means of resting state functional magnetic resonance imaging and transcranial magnetic stimulation in a cross-sectional plus longitudinal study design. The general aim of this study is to better understand neuroplasticity of the developing brain after stroke in order to develop more efficacious therapy and to improve the post-stroke functional outcome.

METHODS

The cross-sectional part of the study will investigate the functional cerebral networks of 35 children with chronic arterial ischaemic stroke (time of the lesion >2 years). In the longitudinal part, 15 children with acute arterial ischaemic stroke (shortly after the acute phase of the stroke) will be included and investigations will be performed 3 times within the subsequent 9 months. We will also recruit 50 healthy controls, matched for age and sex. The neuroimaging and neurophysiological data will be correlated with neuropsychological and neurological variables.

DISCUSSION

This study is the first to combine resting state functional magnetic resonance imaging and transcranial magnetic stimulation in a paediatric population diagnosed with arterial ischaemic stroke. Thus, this study has the potential to uniquely contribute to the understanding of neuronal plasticity in the brains of healthy children and those with acute or chronic brain injury. It is expected that the results will lead to the development of optimal interventions after arterial ischaemic stroke.

Cerebrovascular disorders in childhood

Cerebrovascular problems in childhood include diverse problems of vascular supply to the brain and occur with an overall frequency of from 5 to 8/100000 children/year. Signs and symptoms at manifestation are manifold. They depend not only on localization of the infarction but also on age at injury and specific risk factors. Acute arterial ischemic insult in neonates is oligosymptomatic (short-lasting seizures); hemiparesis is the most common symptom in children. Risk factors are multiple for both neonates and children, with more thromboembolic events in neonates and (infection-related) vasculopathies or cardiac problems in children. MRI (diffusion weighted) is the golden standard for diagnosis. In the absence of evidence for treatment in both groups, guidelines suggest use of platelet aggregation. There are some special indications for anticoagulation. Thrombolysis should be evaluated. Two-thirds of children and neonates face lifelong neurological and neuropsychological problems. Spinal artery ischemia presents with acute spinal symptoms, mostly paraplegia. Risk factors and prognosis are similar to cerebral insults. Sinus venous thromboses are significantly less common. Provoking factors in newborns are mainly neonatal problems, and in children infections, especially in the ENT region. For diagnosis the delta sign in CT is less sensitive than MR/MR venography. In the absence of any evidence, LMWH or heparinization for 3-6 months are recommended. Prognosis is better in children than in neonates. Deep vein thrombosis and/or young age worsen the outcome.