The course and outcome of unilateral intracranial arteriopathy in 79 children with ischaemic stroke

The roles of anatomic factors, thrombophilia, and antithrombotic therapies in childhood-onset arterial ischemic stroke

Childhood-onset arterial ischemic stroke (AIS) is a rare disorder with high risks of both recurrent stroke and life-long neurological morbidity. Anatomic risk factors for primary and/or recurrent AIS include a venous thrombotic source for paradoxical embolism via a patent foramen ovale, primary cardioembolism, extracranial dissection, and intracranial arteriopathies, among others. Genetic and acquired thrombophilias are common, some of which have been shown to have prognostic influence on risk of recurrent AIS. While knowledge of childhood AIS risk factors has grown considerably in recent years, an evidence-based understanding of optimal antithrombotic therapy strategies has not yet been attained. Consensus-based guidelines have been developed, but future research must emphasize identification of additional prognostic factors and the initiation of cooperative randomized controlled clinical trials.

Genetic and clinical characteristics of Moyamoya disease in Europeans

The European form of Moyamoya disease clearly differs from the Asian form. Clinically the timing of vasculopathy onset and a lower rate of hemorrhage are striking as compared to the Asian Moyamoya disease.Single nucleotide polymorphisms that play a role in atherosclerosis, vascular growth and transformation processes have been found to be associated with the European form. Candidate gene associations found in Asian patients could not be replicated in European patients.To elucidate the characteristics, we describe the clinical features as well as the genetic findings that we have found in our combined cohorts of European patients.

Cerebral angiopathies as a cause of ischemic stroke in children: differential diagnosis and treatment options

BACKGROUND

Ischemic stroke in children can present with an epileptic seizure or be initially asymptomatic. The median time to diagnosis is 24 hours.

METHODS

This review is based on a selective literature search, with additional consideration of published guidelines and the authors' personal experience.

RESULTS

In Europe and the USA, the combined incidence of ischemic and hemorrhagic stroke in childhood is 2.5 to 10 per 100 000 children per year. 40% of ischemic strokes in childhood occur after an infectious illness or in association with a congenital heart defect, sickle-cell anemia, or a coagulopathy. Arterial dissection and chronic, progressive cerebral arteriopathies, particularly moyamoya disease, each account for up to 10% of childhood strokes. Magnetic resonance imaging can be used to demonstrate infarcts and to display the perfusion of ischemic areas and the surrounding brain tissue; arterial and venous occlusions can be defined more precisely. Children with arterial dissection, vasculitis, and para-infectious cerebral ischemia should be treated empirically, with medications and supportive care, according to the treatment plans developed for adults. For patients with moyamoya disease, surgical revascularization with extra-intracranial bypass techniques is recommended.

DISCUSSION

The current data provide an inadequate evidence base for the treatment of stroke in children. Potential revascularization or thrombolysis must be discussed individually in each case. For the treatment of temporary, para-infectious cerebral ischemia, hemodynamic optimization is an available option. Better evidence is needed regarding the surgical treatment of moyamoya disease.

Identification of novel biomarker candidates by proteomic analysis of cerebrospinal fluid from patients with moyamoya disease using SELDI-TOF-MS

Background

Moyamoya disease (MMD) is an uncommon cerebrovascular condition with unknown etiology characterized by slowly progressive stenosis or occlusion of the bilateral internal carotid arteries associated with an abnormal vascular network. MMD is a major cause of stroke, specifically in the younger population. Diagnosis is based on only radiological features as no other clinical data are available. The purpose of this study was to identify novel biomarker candidate proteins differentially expressed in the cerebrospinal fluid (CSF) of patients with MMD using proteomic analysis.

Methods

For detection of biomarkers, CSF samples were obtained from 20 patients with MMD and 12 control patients. Mass spectral data were generated by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) with an anion exchange chip in three different buffer conditions. After expression difference mapping was undertaken using the obtained protein profiles, a comparative analysis was performed.

Results

A statistically significant number of proteins (34) were recognized as single biomarker candidate proteins which were differentially detected in the CSF of patients with MMD, compared to the control patients (p < 0.05). All peak intensity profiles of the biomarker candidates underwent classification and regression tree (CART) analysis to produce prediction models. Two important biomarkers could successfully classify the patients with MMD and control patients.

Conclusions

In this study, several novel biomarker candidate proteins differentially expressed in the CSF of patients with MMD were identified by a recently developed proteomic approach. This is a pilot study of CSF proteomics for MMD using SELDI technology. These biomarker candidates have the potential to shed light on the underlying pathogenesis of MMD.

[Hypoplasia of the internal carotid artery: a rare cause of cerebral ischemic stroke in children]

Hypoplasia of the carotid arteries is a rare congenital anomaly which, when symptomatic, presents as cerebral ischemia or hemorrhage. We report a case of hypoplasia of the carotid arteries revealed by cerebral ischemic stroke in an infant with hereditary spherocytosis. The diagnosis was confirmed by MR angiography. We describe this rare cause of stroke in children and the characteristics of its association with hereditary spherocytosis.

Childhood Posterior Circulation Arterial Ischemic Stroke

Background and Purpose— Limited data exist on childhood posterior circulation arterial ischemic stroke (PCAIS). We describe clinical and radiological features of childhood PCAIS to determine whether there are differences in infarct topography, vascular abnormalities, risk factors, and stroke subtypes when compared to adults.

Methods— Children with radiologically confirmed PCAIS were prospectively identified from August 2002 to February 2008. Infarcts were divided into proximal, middle, and distal posterior circulation segments utilizing an adult topographical classification system. Vascular abnormalities were described in terms of location, severity, and evolution over time. A pediatric modification of the TOAST classification system was used to define stroke subtypes.

Results— Twenty seven (37%) of 73 children recruited to our registry had 34 radiologically confirmed PCAIS events. Infarct location was distal (25), middle (2), proximal (1), and multiple segments (6). Fourteen events were associated with single infarcts and 20 were associated with multiple infarcts. Magnetic resonance angiography was abnormal in 16 of 25 children with PCAIS at presentation with stenosis (8) or occlusion (8). Vascular lesions progressed (5), transiently worsened before stabilizing (2), remained stable or improved (8), or normalized (1) over 12 months. Stroke subtypes included nonprogressive steno-occlusive cerebral arteriopathy (9), cardioembolic (4), dissection (3), Moyamoya syndrome (3), other determined (4), probable (1), and undetermined etiology (3). Fifty-two percent of children had recurrent posterior (6) or anterior (8) strokes.

Conclusions— Nonprogressive arteriopathies are the most common cause of childhood PCAIS, usually affecting distal segments. Atherosclerosis-related risk factors do not play an important role in stroke causation. PCAIS is frequently associated with recurrent events.

Recent advances in childhood arterial ischemic stroke

Although many underlying diseases have been reported in the setting of childhood arterial ischemic stroke, emerging research demonstrates that non-atherosclerotic intracerebral arteriopathies in otherwise healthy children are prevalent. Minor infections may play a role in arteriopathies that have no other apparent underlying cause. Although stroke in childhood differs in many aspects from adult stroke, few systematic studies specific to pediatrics are available to inform stroke management. Treatment trials of pediatric stroke are required to determine the best strategies for acute treatment and secondary stroke prevention. The high cost of pediatric stroke to children, families, and society demands further study of its risk factors, management, and outcomes. This review focuses on the recent findings in childhood arterial ischemic stroke.

Diagnosis and management of pediatric arterial ischemic stroke

Pediatric stroke is among the top 10 causes of death in children and an important cause of chronic morbidity, with an incidence of 3.3/100,000 children/year. Risk factors associated with stroke in children include cardiac diseases, hematologic and vascular disorders, and infection. Clinical presentation varies depending on age, underlying cause, and stroke location. Antithrombotics and anticoagulants are used in the treatment of pediatric stroke; however, there are no established guidelines for the use of these agents in children. In this article we review the cause, pathophysiology, clinical presentation, diagnosis, acute management, secondary prevention, and outcome of children with stroke. The approach to patients with sickle cell disease and Moyamoya disease is also discussed. Up to date studies to determine the optimal acute treatment of childhood stroke and secondary prevention and risk factor modification are critically needed.

The epidemiology of childhood stroke

This paper reviews the epidemiology of childhood stroke. Stroke is an important condition in children. It is one of the top ten causes of childhood death and there is a high risk of serious morbidity for the survivors. Epidemiological data are an integral part of disease understanding and high quality studies are required to ensure that this data is robust. Incidence rates from population-based studies vary from 1.3 per 100,000 to 13.0 per 100,000. Factors found to influence incidence rates include age, gender, and ethnicity but there are also many inherent differences between studies. Temporal analysis of mortality rates from childhood stroke shows falling rates but there has been little long-term study of changes in incidence rates. Improved epidemiological data should be a goal of the national and international collaborative networks that are studying childhood stroke.

Virus vasculopathy and stroke: an under-recognized cause and treatment target

While arteriosclerotic disease and hypertension, with or without diabetes, are the most common causes of stroke, viruses may also produce transient ischemic attacks and stroke. The three most-well studied viruses in this respect are varicella zoster virus (VZV), cytomegalovirus (CMV) and human immunodeficiency virus (HIV), all of which are potentially treatable with antiviral agents. Productive VZV infection in cerebral arteries after reactivation (zoster) or primary infection (varicella) has been documented as a cause of ischemic and hemorrhagic stroke, aneurysms with subarachnoid and intracerebral hemorrhage, arterial ectasia and as a co-factor in cerebral arterial dissection. CMV has been suggested to play a role in the pathogenesis of arteriosclerotic plaques in cerebral arteries. HIV patients have a small but definite increased incidence of stroke which may be due to either HIV infection or opportunistic VZV infection in these immunocompromised individuals. Importantly, many described cases of vasculopathy in HIV-infected patients were not studied for the presence of anti-VZV IgG antibody in CSF, a sensitive indicator of VZV vasculopathy. Unlike the well-documented role of VZV in vasculopathy, evidence for a causal link between HIV or CMV and stroke remains indirect and awaits further studies demonstrating productive HIV and CMV infection of cerebral arteries in stroke patients. Nonetheless, all three viruses have been implicated in stroke and should be considered in clinical diagnoses.

Stroke and cerebrovascular disorders

PURPOSE OF REVIEW

Stroke and cerebrovascular disorders in childhood are a cause for significant morbidity in childhood. There is growing emphasis on understanding the mechanisms of stroke so as to inform developments in investigation and management.

RECENT FINDINGS

Advances have been made in the classification of pediatric stroke, aided by clinical and radiological recognition of patterns of injury and differential outcomes dependent on timing of stroke occurrence. Risk factors are multifactorial, with evidence of geographical and national variation. Causality, however, remains difficult to prove. Recent studies highlight a significant association between stroke recurrence and outcome and the presence of steno-occlusive arterial disease, Moyamoya disease and progressive arteriopathy. Focal arteriopathy of childhood is a new term proposed to refine the nomenclature of childhood arteriopathy. The association between infection and childhood stroke is increasingly recognized, with associations with sinovenous thrombosis and childhood arteriopathy. The recommendation to screen for arteriopathy in genetic conditions such as sickle cell disease is now extended to include children with neurofibromatosis type 1. Perfusion and magnetic resonance wall imaging have helped in the determination of the cause of stroke with impact on management in adults. Two new treatment guidelines have been published (American Heart Association and Chest), but barriers remain to the use of thrombolysis in childhood stroke.

SUMMARY

Continued developments in understanding and practice in childhood stroke are encouraging. However, the absence of clinical trials and evidence-based guidelines is limiting. The conduct of such trials is a goal towards which the International Pediatric Stroke Study is moving.

Varicella zoster virus vasculopathies: diverse clinical manifestations, laboratory features, pathogenesis, and treatment

Vasculopathies caused by varicella zoster virus (VZV) are indicative of a productive virus infection in cerebral arteries after either reactivation of VZV (shingles) or primary infection (chickenpox). VZV vasculopathy can cause ischaemic infarction of the brain and spinal cord, as well as aneurysm, subarachnoid and cerebral haemorrhage, carotid dissection, and, rarely, peripheral arterial disease. VZV vasculopathy in immunocompetent or immunocompromised individuals can be unifocal or multifocal with deep-seated and superficial infarctions. Lesions at the grey-white matter junction on brain imaging are a clue to diagnosis. Involvement of both large and small arteries is more common than that of either alone. Most patients have a mononuclear cerebrospinal fluid pleocytosis, often with red blood cells. Cerebrospinal fluid pleocytosis and rash are absent in about a third of cases. Anti-VZV IgG antibody in the cerebrospinal fluid is found more frequently than VZV DNA. In recent years, the number of recognised VZV vasculopathies has grown, and accurate diagnosis is important for the effective treatment of these disorders.

Stroke: Improving characterization of childhood cerebral arteriopathies

There is notable variation in incidence, presentation, risk factors, and prognosis for strokes occurring in children. At present, there is no stroke classification system specifically tailored to the multiple risk factors and etiologies of pediatric stroke. The study by the international Pediatric Stroke Study investigators on predictors of cerebral arteriopathy in children with arterial ischemic stroke deserves special attention in planning secondary stroke prevention strategies in this population of patients.