Predicting Ischemic Risk Using Blood Oxygen Level-Dependent MRI in Children with Moyamoya.

BACKGROUND AND PURPOSE: Moyamoya is a progressive steno-occlusive arteriopathy. MR imaging assessment of cerebrovascular reactivity can be performed by measuring the blood oxygen level-dependent cerebrovascular reactivity response to vasoactive stimuli. Our objective was to determine whether negative blood oxygen level-dependent cerebrovascular reactivity status is predictive of ischemic events in childhood moyamoya. MATERIALS AND METHODS: We conducted a retrospective study of a consecutive cohort of children with moyamoya who underwent assessment of blood oxygen level-dependent cerebrovascular reactivity. The charts of patients with written informed consent were reviewed for the occurrence of arterial ischemic stroke, transient ischemic attack, or silent infarcts. We used logistic regression to calculate the OR and 95% CI for ischemic events based on steal status. Hazard ratios for ischemic events based on age at blood oxygen level-dependent cerebrovascular reactivity imaging, sex, and moyamoya etiology were calculated using Cox hazards models. RESULTS: Thirty-seven children (21 female; median age, 10.7 years; interquartile range, 7.5-14.7 years) were followed for a median of 28.8 months (interquartile range, 13.7-84.1 months). Eleven (30%) had ischemic events, 82% of which were TIA without infarcts. Steal was present in 15 of 16 (93.8%) hemispheres in which ischemic events occurred versus 25 of 58 (43.1%) ischemic-free hemispheres (OR = 19.8; 95% CI, 2.5-160; P = .005). Children with idiopathic moyamoya were at significantly greater risk of ischemic events (hazard ratio, 3.71; 95% CI, 1.1-12.8; P = .037). CONCLUSIONS: Our study demonstrates that idiopathic moyamoya and the presence of steal are independently associated with ischemic events. The use of blood oxygen level-dependent cerebrovascular reactivity could potentially assist in the selection of patients for revascularization surgery and the direction of therapy in children with moyamoya.

Breath-Hold Blood Oxygen Level-Dependent MRI: A Tool for the Assessment of Cerebrovascular Reserve in Children with Moyamoya Disease.

BACKGROUND AND PURPOSE: There is a critical need for a reliable and clinically feasible imaging technique that can enable prognostication and selection for revascularization surgery in children with Moyamoya disease. Blood oxygen level-dependent MR imaging assessment of cerebrovascular reactivity, using voluntary breath-hold hypercapnic challenge, is one such simple technique. However, its repeatability and reliability in children with Moyamoya disease are unknown. The current study sought to address this limitation. MATERIALS AND METHODS: Children with Moyamoya disease underwent dual breath-hold hypercapnic challenge blood oxygen level-dependent MR imaging of cerebrovascular reactivity in the same MR imaging session. Within-day, within-subject repeatability of cerebrovascular reactivity estimates, derived from the blood oxygen level-dependent signal, was computed. Estimates were associated with demographics and intellectual function. Interrater reliability of a qualitative and clinically applicable scoring scheme was assessed. RESULTS: Twenty children (11 males; 12.1 ± 3.3 years) with 30 MR imaging sessions (60 MR imaging scans) were included. Repeatability was "good" on the basis of the intraclass correlation coefficient (0.70 ± 0.19). Agreement of qualitative scores was "substantial" (κ = 0.711), and intrarater reliability of scores was "almost perfect" (κ = 0.83 and 1). Younger participants exhibited lower repeatability (P = .027). Repeatability was not associated with cognitive function (P > .05). However, abnormal cerebrovascular reactivity was associated with slower processing speed (P = .015). CONCLUSIONS: Breath-hold hypercapnic challenge blood oxygen level-dependent MR imaging is a repeatable technique for the assessment of cerebrovascular reactivity in children with Moyamoya disease and is reliably interpretable for use in clinical practice. Standardization of such protocols will allow further research into its application for the assessment of ischemic risk in childhood cerebrovascular disease.

Clinical and Imaging Characteristics of Arteriopathy Subtypes in Children with Arterial Ischemic Stroke: Results of the VIPS Study.

BACKGROUND AND PURPOSE: Childhood arteriopathies are rare but heterogenous, and difficult to diagnose and classify, especially by nonexperts. We quantified clinical and imaging characteristics associated with childhood arteriopathy subtypes to facilitate their diagnosis and classification in research and clinical settings. MATERIALS AND METHODS: The Vascular Effects of Infection in Pediatric Stroke (VIPS) study prospectively enrolled 355 children with arterial ischemic stroke (2010-2014). A central team of experts reviewed all data to diagnose childhood arteriopathy and classify subtypes, including arterial dissection and focal cerebral arteriopathy-inflammatory type, which includes transient cerebral arteriopathy, Moyamoya disease, and diffuse/multifocal vasculitis. Only children whose stroke etiology could be conclusively diagnosed were included in these analyses. We constructed logistic regression models to identify characteristics associated with each arteriopathy subtype. RESULTS: Among 127 children with definite arteriopathy, the arteriopathy subtype could not be classified in 18 (14%). Moyamoya disease (n = 34) occurred mostly in children younger than 8 years of age; focal cerebral arteriopathy-inflammatory type (n = 25), in children 8-15 years of age; and dissection (n = 26), at all ages. Vertigo at stroke presentation was common in dissection. Dissection affected the cervical arteries, while Moyamoya disease involved the supraclinoid internal carotid arteries. A banded appearance of the M1 segment of the middle cerebral artery was pathognomonic of focal cerebral arteriopathy-inflammatory type but was present in <25% of patients with focal cerebral arteriopathy-inflammatory type; a small lenticulostriate distribution infarct was a more common predictor of focal cerebral arteriopathy-inflammatory type, present in 76%. It remained difficult to distinguish focal cerebral arteriopathy-inflammatory type from intracranial dissection of the anterior circulation. We observed only secondary forms of diffuse/multifocal vasculitis, mostly due to meningitis. CONCLUSIONS: Childhood arteriopathy subtypes have some typical features that aid diagnosis. Better imaging methods, including vessel wall imaging, are needed for improved classification of focal cerebral arteriopathy of childhood.

Unfractionated heparin dosing in young infants: clinical outcomes in a cohort monitored with anti-factor Xa levels.

BACKGROUND: Unfractionated heparin (UFH) is a widely used anticoagulant. Current American College of Chest Physicians guidelines for infants extrapolated from adults recommend 28 U kg(-1) h(1) of UFH to achieve an anti-factor Xa level of 0.35-0.7 IU mL(-1). OBJECTIVE: To assess the profile of anti-FXa-based UFH dosing guidelines in infants. PATIENTS/METHODS: We included all infants aged < 6 months treated with per-protocol intravenous UFH at the Hospital for Sick Children, Toronto, over a 3.5-year period. RESULTS: Of 100 infants, 11% achieved sustained therapeutic anti-FXa levels with current dose recommendations. Only 15% achieved target anti-FXa levels within 24 h with per-protocol dose escalations. Seventeen per cent of patients never achieved therapeutic anti-FXa levels, despite up to 60 days of therapy and triple the recommended dose. The median dose needed to achieve therapeutic anti-FXa levels in the remaining 83 infants was 33 U kg(-1) h(-1) (interquartile range, 30-36). Two in three infants had decreased thrombus size at completion of therapy and no thrombus progression/recurrence, and 11/100 infants suffered major bleeding. Without exclusion of extracorporeal membrane oxygenation patients, an activated partial thromboplastin time (APTT) of > 180 s was detected as a risk factor for major bleeding. CONCLUSIONS: UFH monitoring is challenging in infants. Despite their delay in reaching therapeutic anti-FXa levels, infants monitored with the adult-based anti-FXa range have a high thrombus resolution rate, no thrombus progression, but a relatively high bleeding rate. Extreme APTT elevation may contribute to this bleeding risk, particularly in critically ill patients. Current UFH guidelines for young infants may still be inadequate, and laboratory methods with age-appropriate ranges may be required to further improve clinical outcomes within this population.

Diagnosis of perinatal stroke I: definitions, differential diagnosis and registration.

INTRODUCTION: Perinatal stroke can be divided into three subtypes: ischaemic stroke, either arterial or sinovenous and haemorrhagic stroke. For the sake of universal registration and to perform intervention studies, we propose a detailed diagnostic registration system for perinatal stroke taking 10 variables into account. These variables are discussed here and in the accompanying article. MATERIAL AND RESULTS: Differentiation is needed from focal brain changes as a result of disorders other than stroke, whereby accurate timing is possible only when early neonatal imaging is available. Detailed templates are presented for arterial and venous vascular classification. AIS is further subdivided into single territory and complex infarction and some stratification is proposed in the complicated stroke group. This registration system has been applied to a retrospective cohort of 134 newborns with stroke (single-centre observation from 1999 to 2007) and the results are compared with published data. By applying this registration system, intervention studies for one homogeneous stroke type (e.g. complete middle cerebral artery stroke) may be facilitated. CONCLUSION: Ten variables may be sufficient to register a perinatal stroke. These include gestational age, birthweight, gender, delivery mode, time of detection, presentation, type of stroke, vessel affected or type of cavity, imaging method at detection and clinical context.

Paediatric stroke. Who should be treated?

The past decade has seen a dramatic increase in pediatric stroke research. However few studies have addressed antithrombotic safety or effectiveness. Three paediatric stroke guidelines combining research data with expert consensus have been published in the past five years. For most patients treatment recommendations are consistent. Newborns with arterial ischaemic stroke (AIS) rarely require antithrombotic treatment given their extremely low risk of recurrence. In children with AIS a substantial recurrence risk means that antithrombotic treatment is required unless contraindicated. Anticoagulation (heparins, warfarin) is recommended for possible or established dissection and cardiogenic embolism. Antiplatelet treatment is recommended for other children with AIS. For neonatal cerebral sinovenous thrombosis (CSVT) most centers provide initial anticoagulation in the absence of haemorrhagic contra indications, and otherwise, monitor for propagation. Children with CSVT, even with haemorrhagic infarction, more consistently receive anticoagulation, as in adults. While more studies are necessary, current treatment guidelines offer an interim option for guiding the treatment of paediatric stroke.

Frequency and topographic distribution of brain lesions in pediatric cerebral venous thrombosis.

BACKGROUND AND PURPOSE: Cerebral sinovenous thrombosis (CSVT) is increasingly encountered in children, including neonates. The purpose of this study was to assess the frequency and topographic distribution of parenchymal brain lesions associated with CSVT in children and to compare these with the known anatomic venous drainage pathways. MATERIALS AND METHODS: Brain CT/CT venograms and/or MR imaging/MR venograms of 71 consecutive patients with CSVT were reviewed retrospectively. The patients were grouped into neonates, infants, and older children. The site of CSVT, the location and size of the brain lesions, and the presence of hemorrhage were documented. The frequency of the brain lesions was calculated. RESULTS: There were 34 neonates, 10 infants, and 27 older children with CSVT who were included. The most common sites of CSVT were the transverse sinuses, the superior sagittal sinus, and the straight sinus. Overall, 37 of 71 children with CSVT had parenchymal brain lesions. There were 21 of 34 neonates, 4 of 10 infants, and 12 of 27 older children who had brain lesions. The most common locations were in the frontal and parietal lobes. The topographic distribution of lesions correlated with the corresponding venous drainage territory in 16 of 21 neonates, all infants, and all older children. The neonates had smaller-sized lesions. Brain lesions were hemorrhagic in 76% of neonates, 75% of infants, and 33% of older children. CONCLUSION: The topographic distribution of brain lesions associated with CSVT correlates with the known drainage territories of the dural venous sinus in children.

Angiography of primary central nervous system angiitis of childhood: conventional angiography versus magnetic resonance angiography at presentation.

BACKGROUND AND PURPOSE: To systematically analyze conventional angiographic (CA) features of children with primary central nervous system angiitis (cPACNS), to compare and correlate CA and MR angiography (MRA) lesion characteristics, and to define the sensitivity and specificity of MRA with CA as a reference standard. METHODS: A retrospective, single-center cohort study of consecutive patients with cPACNS was performed. Patients with CA and MRA studies at diagnosis were included. Imaging studies were blindly reviewed by 2 neuroradiologists using a standard analysis protocol. CA and MRA studies were compared using nonparametric analysis. RESULTS: Of 45 patients with MRA at diagnosis, there were 25 for whom CA and MRA studies were performed within 1 month of each other. These comprised the study group. The CA distribution of lesions was multifocal (76%) and proximal (86%) (P < .05) with a trend toward unilaterality (P = .06) with anterior circulation involvement (P = .08). The sensitivity and specificity of MRA for CA abnormality was 70% and 98%, respectively. There was no significant difference between MRA and CA for lesion detection or characterization (P = .87), and the modalities showed a fair correlation (kappa = 0.4). CONCLUSION: Angiographic lesions are multifocal and occur proximally and unilaterally within the anterior circulation. There is no significant difference in the ability of MRA to detect and characterize lesions when compared with CA.

MR imaging and angiography of primary CNS vasculitis of childhood.

BACKGROUND AND PURPOSE: Primary angiitis of the central nervous system of childhood (cPACNS) is a rare and ill-defined disease. In the absence of a brain biopsy, the diagnosis is based on typical clinical and imaging abnormalities. The aim of this study was to analyze systematically the MR imaging and MR angiographic (MRA) abnormalities in a large cohort of children with cPACNS. METHODS: We analyzed the MR imaging features of a single pediatric center cohort of 45 cPACNS patients. MR imaging studies were performed for all patients, and both MR imaging and MRA were performed for 42 patients, who formed the cohort for review of the presence and correlation of lesions. Proportions were calculated by using the Fisher exact test, and agreement between MR imaging and MRA was calculated by using the McNemar test. The sensitivity of each diagnostic technique was established. RESULTS: The most-common pattern of parenchymal abnormality was multifocal, unilateral involvement, each in 42/45 patients (93%). The lateral lenticulostriate artery terrritory was affected in 56% of cases, with involvement of a supratentorial deep gray matter structure in 91%. No infratentorial lesion occurred in the absence of supratentorial abnormality. MRA was normal in 12/42 patients (28.6%). Among the abnormal studies, stenosis was detected on MRA in 83% and was "benign" in appearance in 73% of patients and "aggressive" in 16.7%. Involvement was proximal in 83% and distal in 27% of patients. Multiple ipsilateral lesions were seen in 63%. MR imaging was abnormal in every patient where MRA was abnormal. With the assumption of MR imaging as the gold standard, the sensitivity of MRA was 72%. The agreement between MR imaging and MRA for abnormality was significant (P = .04). CONCLUSION: We have illustrated the MR imaging and MRA appearances of cPACNS in the largest cohort to date. Both parenchymal and vascular lesions were predominantly proximal, unilateral, and multifocal within the anterior circulation. There was good agreement between MR imaging and MRA for lesion location. MR imaging findings were abnormal in all cases at diagnosis, and this remains the most sensitive technique to the detection of vasculitis.

Increased anticardiolipin antibody IgG titers do not predict recurrent stroke or TIA in children.

BACKGROUND: Increased anticardiolipin antibody (ACLA) immunoglobulin (Ig) G titers are commonly found in children with arterial ischemic stroke (AIS) or TIA (AIS/TIA). The associated risk of recurrent thromboembolism is unknown. OBJECTIVE: To determine the risk of recurrent thromboembolism associated with persistently increased ACLA titers of the IgG isotype in children with AIS/TIA. METHODS: The authors studied a cohort of children surviving first AIS/TIA tested by standardized ELISA for beta2-glycoprotein I-dependent ACLA of the IgG isotype. Children with ACLA titers >15 IgG phospholipid (GPL) units (per manufacturer's cutoff point) on more than two occasions > or =6 weeks apart were classified as ACLA-positive (ACLA+) and compared with ACLA-negative (ACLA-) children with respect to recurrent thromboembolic events (AIS/TIA, sinovenous thrombosis, and extracerebral thromboembolism). RESULTS: The authors recruited 34 ACLA+ children and 151 ACLA- children. Most ACLA+ children (30/34; 88%) had ACLA titers < or =40 GPL units. During the follow-up period (median duration, 2.8 years for ACLA+ children and 3.0 years for ACLA- children), AIS/TIA recurred in 26% of ACLA+ children and in 38% of ACLA- children; none developed sinovenous thrombosis or extracerebral thromboembolism. Based on survival analysis, this difference was nonsignificant (p = 0.54). Using binary partition evaluation, no titer criteria for ACLA positivity (range, 0 to 60 GPL units) predicted recurrent AIS/TIA. CONCLUSION: In children surviving arterial ischemic stroke/TIA, increased anticardiolipin antibody immunoglobulin G titers do not predict recurrent thromboembolism.

Venous thrombosis in children.

Venous thromboembolic (VTE) events are being increasingly diagnosed in systemic and cerebral vessels in children. Systemic VTE are increasing in children as a result of therapeutic advances and improved clinical acumen in primary illnesses that previously caused mortality. The epidemiology of systemic VTE has been studied in international registries. In children older than 3 months, teenagers are the largest group developing VTE. The most common etiologic factor is the presence of central venous lines. Clinical studies have determined the most sensitive diagnostic method for diagnosing upper system VTE are ultrasound for jugular venous thrombosis and venography for intrathoracic vessels. However, the most sensitive diagnostic methods for lower system VTE and pulmonary embolism (PE) have not been established. Treatment studies for VTE consist of inadequately powered randomized controlled trials or prospective cohort studies. The long-term outcome of systemic VTE, post-thrombotic syndrome, has been reported in children. Cerebral sinovenous thrombosis (CSVT) is becoming increasingly diagnosed in children due to the recognition of the associated subtle clinical symptoms and improved cerebrovascular imaging. The etiology of CSVT includes thrombophilia, head and neck infections, and systemic illness. Estimates of the incidence and outcome of childhood CSVT have recently become available through the Canadian Pediatric Ischaemic Stroke Registry. Clinical studies have not yet been carried out in children to determine the best method of diagnosis or treatment. There have only been case-series studies carried out in the treatment of CSVT. Properly designed clinical trials are urgently required in children with systemic VTE/PE and CSVT to define the best methods of diagnosis, treatment and long-term management.

Vasogen's immune modulation therapy (IMT) improves postischemic foot skin blood flow and transcutaneous pO(2) recovery rates in patients with advanced peripheral arterial occlusive disease.

AIM: Vasogen's immune modulation therapy (IMT)* involves the ex vivo exposure of a sample of autologous blood to 3 oxidative stress factors (heat, an oxidative environment, and ultraviolet light), followed by intramuscular re-injection. The primary objective of this study was to assess the effect of Vasogen's IMT on skin blood flow in patients with symptomatic peripheral arterial occlusive disease (PAOD). METHODS: In a double-blind, placebo-controlled pilot study, 18 patients with moderately advanced PAOD were randomized to receive 2 courses each of 6 intramuscular injections of either saline or Vasogen's IMT over a 9-week period. Dorsal foot skin blood flow was assessed directly using laser Doppler fluxmetry (LDF) and indirectly using measurement of transcutaneous pO(2) (tcpO(2)). Key outcome measures of skin blood flow were, for LDF: resting values, peak postischemic values, and the total time to reach peak values following release from 4 min of total foot ischemia and, for tcpO(2): resting values and the time for tcpO(2) to reach 50% of the pre-ischemia value. Measurements were carried out at baseline, at weeks 3, 6, and 9, and at 2 months post-therapy. RESULTS: No significant differences were detected between groups for resting or peak postischemic LDF values for dorsal foot skin blood flow. Patients randomised to IMT experienced a progressive decrease in the time to peak postischemic skin blood flow, reaching statistical significance at 2 months. Treated patients experienced a 26.1 s decrease in time to peak blood flow (p=0.026) vs a 7.9 s decrease in the placebo group (p=ns). Similar but less striking results were achieved for tcpO(2) recovery time to 50% of pre-ischemia values (treated group, p=0.035; placebo group, p=ns). CONCLUSION: Vasogen's IMT improved recovery rates of postischemic dorsal foot skin blood flow in a group of patients with moderately advanced PAOD, probably due to improved endothelial function.

Anticoagulation for cerebral sinus thrombosis.

BACKGROUND: Treatment of cerebral sinus thrombosis with anticoagulants has been controversial. Anticoagulants may prevent new venous infarcts, neurologic deterioration, and pulmonary embolism but may also promote haemorrhages. OBJECTIVES: To review the available evidence regarding the effectiveness and safety of anticoagulant therapy in patients with confirmed cerebral sinus thrombosis. SEARCH STRATEGY: We searched the Cochrane Stroke Group Trials Register (last searched 18 March 2002). We also searched MEDLINE (1966-Oct 2001), EMBASE (1980-Feb 2002) and the Cochrane Controlled Trials Register (Cochrane Library, 2002 Issue 1) and contacted authors to identify additional published and unpublished studies. SELECTION CRITERIA: Unconfounded randomised controlled trials in which anticoagulant therapy was compared with placebo or open control in patients with cerebral sinus thrombosis (confirmed by intra-arterial contrast or magnetic resonance angiography). DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted outcomes for each of the two treatment groups (anticoagulant treatment and control). The outcome data for each patient are analysed in the treatment group to which the patient was originally allocated ('intention to treat' analysis). A weighted estimate of the treatment effects across trials (relative risk, absolute risk reduction) is calculated using the Cochrane statistical software. MAIN RESULTS: Two small trials involving 79 patients fulfilled the inclusion criteria. One trial (20 patients) examined the efficacy of intravenous, adjusted dose unfractionated heparin. The other trial (59 patients) examined high dose, body weight adjusted, subcutaneous, low-molecular weight heparin (Nadroparin). Anticoagulant therapy was associated with a pooled relative risk of death of 0.33 (95 % CI 0.08 to 1.21) and of death or dependency of 0.46 (95 % CI 0.16 to 1.31). No new symptomatic intracerebral haemorrhages were observed. One major gastro-intestinal haemorrhage occurred after anticoagulant treatment. Two control patients (placebo) had a diagnosis of probable pulmonary embolism (one fatal). REVIEWER'S CONCLUSIONS: Based upon the limited evidence available, anticoagulant treatment for cerebral sinus thrombosis appeared to be safe and was associated with a potentially important reduction in the risk of death or dependency which did not reach statistical significance.

Thromboembolic disease and antithrombotic therapy in newborns.

This update uses an evidence based approach to analyze and present the epidemiology of neonatal thrombosis, etiologies, currently used techniques for diagnosis with their limitations, and current therapeutic approaches. In addition, the approaches to both prevention and optimal therapies are discussed. In Section I Dr. Paul Monagle addresses the epidemiology of neonatal thrombosis outside of the central nervous system in both arterial and venous locations, and those that occur in utero. The specific contributions of catheters and congenital prothrombotic disorders are delineated. Dr. Monagle also describes currently used techniques for the diagnosis of thrombotic events as well as their limitations and the current therapeutic approaches. In Section II, Dr. Gabrielle deVeber reviews the epidemiology of neonatal thrombosis within the central nervous system, in both arterial and venous locations and those that occur in utero. The neurological presentation, risk factors including congenital prothrombotic disorders, anatomical distribution, diagnostic tests, use of antithrombotic therapy and neurologic outcome of neonates with either sinovenous thrombosis or arterial ischemic stroke are discussed. In Section III, Dr. Anthony Chan reviews the current approaches to the prevention and treatment of neonatal thrombosis. Information on the differences in the response of neonates compared to adults to antithrombotic therapy and new approaches to the prevention and treatment of thrombosis in neonates are emphasized.

Presumed pre- or perinatal arterial ischemic stroke: risk factors and outcomes.

A subgroup of children with arterial ischemic stroke in the pre- or perinatal period present with delayed diagnosis. We identified 22 children who met the following criteria: (1) normal neonatal neurological history, (2) hemiparesis and/or seizures first recognized after two months of age, and (3) computed tomography or magnetic resonance imaging showing remote cerebral infarct. Laboratory evaluations included protein C, protein S, antithrombin, activated protein C resistance screen (APCR), Factor V Leiden (FVL), prothrombin gene defect, methylene tetrahydrofolate reductase variant (MTHFR), anticardiolipin antibody (ACLA), and lupus anticoagulant. Not all children received all tests. Age at last visit ranged from 8 months to 16.5 years (median 4 years). Twelve were boys. Fourteen had left hemisphere infarcts. Median age at presentation was 6 months. Eighteen had gestational complications. Fourteen children had at least transient coagulation abnormalities (ACLA = 11, ACLA + APCR = 1, APCR = 2 with FVL + MTHFR = 1); six of these children had family histories suggestive of thrombosis. Cardiac echocardiogram was unremarkable in the 15 tested. Outcomes included persistent hemiparesis in 22; speech, behavior, or learning problems in 12; and persistent seizures in five, with no evidence of further stroke in any patient. The persistence and importance of coagulation abnormalities in this group need further study.

Cerebral sinovenous thrombosis in children.

BACKGROUND: Cerebral sinovenous thrombosis in children is a serious disorder, and information is needed about its prevention and treatment. METHODS: The Canadian Pediatric Ischemic Stroke Registry was initiated in 1992 at the 16 pediatric tertiary care centers in Canada. Children (newborn to 18 years of age) with symptoms and radiographic confirmation of sinovenous thrombosis were included. RESULTS: During the first six years of the registry, 160 consecutive children with sinovenous thrombosis were enrolled, and the incidence of the disorder was 0.67 cases per 100,000 children per year. Neonates were most commonly affected. Fifty-eight percent of the children had seizures, 76 percent had diffuse neurologic signs, and 42 percent had focal neurologic signs. Risk factors included head and neck disorders (in 29 percent), acute systemic illnesses (in 54 percent), chronic systemic diseases (in 36 percent), and prothrombotic states (in 41 percent). Venous infarcts occurred in 41 percent of the children. Fifty-three percent of the children received antithrombotic agents. Neurologic deficits were present in 38 percent of the children, and 8 percent died; half the deaths were due to sinovenous thrombosis. Predictors of adverse neurologic outcomes were seizures at presentation and venous infarcts. CONCLUSIONS: Sinovenous thrombosis in children affects primarily neonates and results in neurologic impairment or death in approximately half the cases. The occurrence of venous infarcts or seizures portends a poor outcome.

Chickenpox and stroke in childhood: a study of frequency and causation.

BACKGROUND AND PURPOSE: The purpose of this study was to determine whether infection with varicella is causal for arterial ischemic stroke (AIS) in children. METHODS: First, a prospective cohort study was conducted in young children (aged 6 months to 10 years) with AIS at 2 institutions (cohort study). The presence of varicella infection <12 months before AIS was determined and compared with the published frequency of varicella infection in the healthy pediatric population. The clinical and radiographic features of AIS were compared between the varicella and nonvaricella study cohorts. Second, a literature search of varicella-associated AIS was conducted, and the clinical and radiographic features were compared with the study nonvaricella cohort. RESULTS: In the cohort study, 22 (31%) of 70 consecutive children with AIS had a varicella infection in the preceding year compared with 9% in the healthy population. Children in the varicella cohort were more likely to have basal ganglia infarcts (P<0.001), abnormal cerebral vascular imaging (P<0.05), and recurrent AIS or transient ischemic attacks (P<0.05) than those in the nonvaricella cohort. The pooled literature analysis of 51 cases of varicella-associated AIS showed similar findings to the varicella cohort. CONCLUSION: In young children with AIS, there is a 3-fold increase in preceding varicella infection compared with published population rates, and varicella-associated AIS accounts for nearly one third of childhood AIS. Varicella-associated AIS has characteristic features, including a 2-fold increase in recurrent AIS and transient ischemic attacks. Varicella is an important risk factor for childhood AIS.

Isolated angiitis of the CNS in children.

OBJECTIVE: To clarify the clinical features and pathologic manifestations of isolated angiitis of the CNS (IACNS) in children. METHODS: The authors report two new cases and summarize the literature of childhood IACNS confirmed by pathology. RESULTS: IACNS affecting small vessels (n = 5). Neurologic manifestations included headaches, focal seizures, and progressive, behavioral, or multifocal neurologic impairment. MRI showed multifocal, T2-hyperintense, cerebral lesions without mass effect or tumor-like lesions. CSF, erythrocyte sedimentation rate, and cerebral angiograms were often normal.CNS biopsy disclosed a nongranulomatous vasculitis. Children were treated with prednisone alone or combined with cyclophosphamide. One child died. Four children had a favorable outcome. IACNS affecting large and medium arteries (n =5). Three children presented with acute ischemic stroke or TIA. Brain CT showed ischemic infarcts. Two children presented with subarachnoid hemorrhage. In this group, CSF, erythrocyte sedimentation rate, and angiograms were often abnormal. No patient received immunosuppressive therapy. Five children died. Autopsy showed granulomatous IACNS (n =5). CONCLUSIONS: Clinical and radiologic features correlate with the size of affected vessels. Prognosis differs between groups. Potential markers of poor outcome are acute stroke presentation secondary to large and medium-sized artery involvement, granulomatous angiitis, and delayed institution of immunosuppressive therapy.

Neurologic outcome in survivors of childhood arterial ischemic stroke and sinovenous thrombosis.

Ischemic stroke during infancy and childhood has the potential for life-long morbidity. Information on the neurologic outcome of children who survive ischemic stroke is lacking. Children surviving ischemic stroke between January 1, 1995 and July 1, 1999 were prospectively followed. Neurologic deficit severity was based on the Pediatric Stroke Outcome Measure (PSOM) developed in this study and parental response to two recovery questions. Predictor variables for poor outcome were tested. One-hundred twenty-three children with arterial ischemic stroke and 38 with sinovenous thrombosis were followed for a mean of 2.1 years (range, 0.8 to 6.6 years). The primary outcome based on PSOM assessment was: normal, 37%; mild deficit, 20%; moderate deficit, 26%; and severe deficit, 16%. The secondary outcome was full recovery in 45% of patients, based on parental response. The primary and secondary outcome measures were moderately correlated (P < .001; K = 0.5). In bivariate analysis, arterial stroke type, male gender, age of at least 28 days, presence of associated neurologic disorders, and need for rehabilitation therapy after stroke were predictors of poor outcome (P < .05). Multivariate analysis showed that only arterial ischemic stroke, associated neurologic disorders, and presence of rehabilitation therapy were independent predictors of poor outcome (P < .02). Poor outcome in children after ischemic stroke is therefore frequent and more likely in the presence of arterial stroke, rehabilitation therapy, and associated neurologic disorders, which justifies clinical trials of treatment strategies in childhood ischemic stroke.

Prothrombotic disorders and ischemic stroke in children.

Childhood ischemic stroke, including arterial ischemic stroke (AIS) and sinovenous thrombosis (SVT), is relatively rare in children but can result in devastating morbidity and mortality. An understanding of the etiology of childhood stroke is important because strategies for primary and secondary prevention can be devised. Prothrombotic disorders may contribute to the etiology of childhood stroke, and include deficiencies of antithrombin, protein C, protein S, plasminogen, and presence of Factor V Leiden, Prothrombin gene G20210A, dysfibrinogenemia, antiphospholipid antibodies, hyperhomocysteinemia, and elevated lipoprotein (a). The overall incidence of prothrombotic disorders in childhood AIS is estimated to be 20% to 50% in most studies and, in childhood SVT, to be 33% to 99%. In addition, hyperlipidemia, polycythemia, iron deficiency anemia, and platelet disorders may result in a prothrombotic state associated with ischemic stroke. The etiologic contribution of these prothrombotic disorders to initial and recurrent stroke has not been clearly defined; however, additional risk factors are usually present in affected children. Given the prevalence of prothrombotic disorders in childhood stroke, and their likely causative role, children with stroke should be screened for prothrombotic disorders. Future prospective and multicenter studies will elucidate the contribution of specific prothrombotic disorders to initial and recurrent stroke, and optimal therapy.