The first three years of the Swiss Neuropaediatric Stroke Registry (SNPSR): a population-based study of incidence, symptoms and risk factors

Pediatric stroke: clinical findings and radiological approach

This paper focuses on radiological approach in pediatric stroke including both ischemic stroke (Arterial Ischemic Stroke and Cerebral Sinovenous Thrombosis) and hemorrhagic stroke. Etiopathology and main clinical findings are examined as well. Magnetic Resonance Imaging could be considered as the first-choice diagnostic exam, offering a complete diagnostic set of information both in the discrimination between ischemic/hemorrhagic stroke and in the identification of underlying causes. In addition, Magnetic Resonance vascular techniques supply further information about cerebral arterial and venous circulation. Computed Tomography, for its limits and radiation exposure, should be used only when Magnetic Resonance is not available and on unstable patients.

The role of hypoxia-ischemia in term newborns with arterial stroke

The role of generalized hypoxia-ischemia in the genesis of perinatal focal arterial stroke remains puzzling. Animal studies have demonstrated that hypoxia-ischemia may alter blood flow through the ductus venosus, thereby increasing the risk for placental emboli entering the cerebral circulation. A retrospective review was performed of clinical records of all term newborns admitted to a tertiary perinatal center between January 1995 and May 2007 with acute arterial stroke on neuroimaging during the first week of life. Newborns were classified into 2 groups on the basis of neuroimaging abnormalities: stroke alone, or stroke and nonfocal hypoxic-ischemic brain injury. A total of 62 newborns had focal or multifocal stroke, 36 with stroke alone and 26 with stroke with nonfocal hypoxia-ischemia. Multiple risk factors for hypoxia-ischemia occurred in most newborns in both groups. These data indicate that hypoxia-ischemia may play a role in the genesis of stroke in the term newborn with or without evidence of nonfocal hypoxic-ischemic brain injury on neuroimaging.

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.

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.

Cerebral sinus venous thrombosis in Swiss children

AIMo describe the characteristics of paediatric cerebral sinus venous thrombosis (CSVT) in Switzerland.

METHOD

data on clinical features, neuroimaging, risk factors, and treatment were collected for all children in Switzerland younger than 16 years of age who had CSVT between January 2000 and December 2008. A follow-up examination and a cognitive assessment were performed (mean follow-up period 26mo). Differences between neonates and children (patients older than 28d) were assessed and predictors of outcome were determined.

RESULTS

twenty-one neonates (14 males, seven females; mean age 9d, SD 8d) and 44 children (30 males, 14 females; mean age 8y 7mo, SD 4y 5mo) were reported. The incidence of paediatric CSVT in Switzerland was 0.558 per 100000 per year. In neonates, the deep venous system was more often involved and parenchymal injuries were more common. The strongest predictor of poor outcome was neonatal age (odds ratio 17.8, 95% confidence interval 0.847-372.353). Most children showed global cognitive abilities within the normal range, but impairments in single cognitive subdomains were frequent.

INTERPRETATION

paediatric CSVT is rare. Its outcome is poor in neonates. Most children have good neurological outcomes, but some patients have individual neuropsychological impairments.

Childhood stroke in Sweden I: incidence, symptoms, risk factors and short-term outcome

AIM

To evaluate the incidence, presenting symptoms, diagnostic delay, risk factors and short-term outcome of childhood stroke in a population-based cohort of Swedish children.

METHODS

We retrospectively reviewed the records of children experiencing their first stroke during a 7-year period in Uppsala-Örebro Health Care Region covering one-fifth of the Swedish population. Arterial ischaemic stroke (AIS), cerebral sinus venous stroke and nontraumatic haemorrhagic stroke (HS) in children aged > 28 days and < 18 years were included.

RESULTS

We identified 51 children (23 boys and 28 girls; median age 13). The average annual incidence of stroke was 1.8 per 100,000 children. AIS was found in 51% of the children, HS in 41% and cerebral sinus venous stroke in 8%. One-third of the children had underlying diseases, and one-third had vascular malformations. Six girls used oral contraceptives, three of these were smokers and two had iron deficiency anaemia. Two children died in the acute stage (4%), and 40/49 (82%) had some neurological dysfunction at discharge.

CONCLUSION

The incidence of childhood stroke was 1.8 per 100,000 children and year, and the primary mortality was 4%. Risk factors of importance were oral contraceptives, smoking and anaemia in combinations.

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

AIM

The aim of this study was to describe neuroimaging patterns associated with arterial ischaemic stroke (AIS) in childhood and to differentiate them according to stroke aetiology.

METHOD

Clinical and neuroimaging (acute and follow-up) findings were analysed prospectively in 79 children (48 males, 31 females) aged 2 months to 15 years 8 months (median 5 y 3 mo) at the time of stroke by the Swiss Neuropaediatric Stroke Registry from 2000 to 2006.

RESULTS

Stroke was confirmed in the acute period in 36 out of 41 children who underwent computed tomography, in 53 of 57 who underwent T2-weighted magnetic resonance imaging (MRI) and in all 48 children who underwent diffusion-weighted MRI. AIS occurred in the anterior cerebral artery (ACA) in 63 participants and in all cases was associated with lesions of the middle cerebral artery (MCA). The lesion was cortical-subcortical in 30 out of 63 children, cortical in 25 out of 63, and subcortical in 8 of 63 children. Among participants with AIS in the posterior circulation territory, the stroke was cortical-subcortical in 8 out of 16, cortical in 5 of 16, and thalamic in 3 out of 16 children.

INTERPRETATION

AIS mainly involves the anterior circulation territory, with both the ACA and the MCA being affected. The classification of Ganesan is an appropriate population-based classification for our Swiss cohort, but the neuroimaging pattern alone is insufficient to determine the aetiology of stroke in a paediatric population. The results show a poor correlation between lesion pattern and aetiology.

Investigation and management of childhood stroke

It is now clear that a number of paediatric emergencies with a neurological presentation, including hemiparesis, visual loss, seizures and coma, commonly have a vascular basis which may not be obvious on CT scan. Although many children do well, as there is significant mortality as well as morbidity for childhood stroke, in addition to a high risk for recurrence, making a diagnosis in the acute phase important. Venography and arteriography (including the neck vessels if the intracranial vessels are normal) are usually indicated despite the problems i.e. contrast CT requires a high dose of radiation while emergency MR usually requires anaesthesia and conventional arteriography carries a small risk of stroke. Surgical decompression may be life-saving in ischaemic as well as haemorrhagic stroke. It is unusual for children with anterior circulation stroke to be triaged quickly enough (<4.5 h) for thrombolysis but this may occasionally be appropriate in posterior circulation occlusion associated with coma, where the time window is longer (<12 h). Anticoagulation carries relatively low risk and may be of benefit for children with venous sinus thrombosis (acutely and when at risk subsequently) or extracranial dissection. Aspirin to attempt to reduce the recurrence risk is appropriate in the medium term for the majority of patients with arterial ischaemic stroke. Iron and B vitamin deficiencies should be excluded or treated.

Lateralization of cognitive functions after stroke in childhood

RATIONALE

A child's brain shows a remarkable ability to recover from adverse events such as stroke. Language functions recover particularly well, while visuo-spatial skills are more affected by brain damage, regardless of its localization. This study investigated the lateralization of language and visual search after childhood stroke.

METHODS

Ten patients with unilateral stroke (aged 10-19 years, five left-, five right-sided lesion) and 20 healthy controls (aged 8-20 years) completed a neuropsychological test battery and functional magnetic resonance imaging (fMRI) intended to activate predominantly right (visual search) and left-sided functional networks (language).

RESULTS

After stroke, patients demonstrated atypical lateralization of visual search functions (8/10 patients, left lateralization) more often than that of language (4/10 patients, right lateralization). There was a dissociation between the lateralization of productive and semantic language (4/10 patients, 1/20 controls) and between the lateralization of simple and complex visual search (3/10 patients, 3/20 controls). In patients, atypical contralateral activations occurred in the same areas that showed decreasing activation during development in healthy participants.

CONCLUSION

The lateralization of functions depends upon the cognitive function measured. Dissociation between the lateralization of different language or visual search tasks can occur.

Pediatric arterial ischemic stroke

Arterial ischemic stroke (AIS) is a rare disorder in children. Research suggests that risk factors, outcomes, and presentation are different from those of adult stroke. In particular, prothrombotic abnormalities and large vessel arteriopathies that are nonatherosclerotic seem to play a large role in the pathogenesis of childhood AIS. This review examines the epidemiology and etiologies of neonatal and childhood AIS and provides a detailed discussion of approaches to the clinical characterization, diagnostic evaluation, and management. Long-term outcomes of recurrent AIS and neuromotor, speech, cognitive, and behavioral deficits are considered. Emphasis is on evidence underlying current knowledge and key questions for further investigation.

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.

Stroke in children: inherited and acquired factors and age-related variations in the presentation of 48 paediatric patients

AIM

Stroke is relatively rare in children and the clinical presentation of paediatric stroke is often subtle. Numerous predisposing risk factors are known, and these can be both inherited and acquired. They include cardiac disease, vascular abnormalities, endothelial damage, infectious diseases, collagen tissue diseases, certain inborn errors of metabolism and anticardiolipin antibody, lupus anticoagulant and deficiencies of protein C, protein S, antithrombin or plasminogen. In addition, abnormal activated protein C resistance (or Factor V Leiden), Factor II G20219A variant, and the thermolabile variant of methylenetetrahydrofolate reductase (MTHFR C677T) need to be considered.

METHODS

To explore the prevalence of different predisposing conditions in paediatric stroke patients, we evaluated 48 patients, including subjects with ischaemic and haemorrhagic stroke subtypes.

RESULTS

Only 7 out of 48 (14.5%) had no recognizable risk factors: the majority of paediatric stroke patients had pre-existing risk factors that predisposed to the condition. The major genetic risk factor in our series of patients was homozygosity for the MTHFR C677T mutation (7 out of 48 patients); three more patients were found to be heterozygous for the Factor V Leiden mutation. Acquired predisposing conditions were present in 23 out of 48 patients and included pulmunar stenosis, head trauma, hyperlipidaemia and varicella infection. A total of 17 patients had both genetic and acquired predisposing factors.

CONCLUSION

Our results emphasize that multiple predisposing risk factors commonly predispose to paediatric stroke. In addition, the primary clinical presentation appeared to differ between the older and younger children: hemiparesis was the typical presentation in children <1 year of age while seizure predominated in older children.

Pediatric stroke in the United States and the impact of risk factors

One approach to studying pediatric stroke is to analyze a national database that contains data on a significant number of children. We examined an administrative dataset of hospital discharges from the United States, Kids' Inpatient Database 2003 (KID2003), for ICD-9 codes associated with hemorrhagic or ischemic stroke in children aged >30 days to 20 years. 3156 children were discharged with a diagnosis of ischemic stroke and 2022 with hemorrhagic stroke after statistical weighting. The odds for a male discharged with hemorrhagic stroke was 1.5 (CI: 1.35-1.68) and for ischemic stroke was 1.37 (CI: 1.24-1.51) compared with a female. The odds for males discharged with a stroke were greatest for ages 16 to 20 years and least for 4 years. This study confirms a male predominance for stroke. The odds for hospitalization with a stroke diagnosis are greatest in very young and older adolescent males. Hemorrhage is an important stroke subtype in children.

Arterial ischemic stroke in children--recent advances

Childhood stroke syndromes are an important cause of mortality and morbidity. This paper focuses on the recent advances in arterial ischaemic stroke beyond the neonatal period. Vascular risk factors are identified in the majority of children and guide both acute and longer term treatments, as well as determining prognosis. Contrary to popular belief many children have residual impairments encompassing a wide range of domains. National and international collaborations are facilitating an increase in the understanding of childhood stroke and have the eventual aim of conducting trials of potential therapeutic interventions.

Pediatric arterial ischemic stroke

Arterial ischemic stroke (AIS) is a rare disorder in children. Research suggests that risk factors, outcomes, and presentation are different from those of adult stroke. In particular, prothrombotic abnormalities and large vessel arteriopathies that are nonatherosclerotic seem to play a large role in the pathogenesis of childhood AIS. This review examines the epidemiology and etiologies of neonatal and childhood AIS and provides a detailed discussion of approaches to the clinical characterization, diagnostic evaluation, and management. Long-term outcomes of recurrent AIS and neuromotor, speech, cognitive, and behavioral deficits are considered. Emphasis is on evidence underlying current knowledge and key questions for further investigation.

Risk factors and outcomes of childhood ischemic stroke in Taiwan

In this retrospective study, we reviewed the charts and collected clinical and radiographic data on children (age range, 1 month to 18 years) with symptoms and radiographic confirmation of ischemic stroke for the period of January 1996 to July 2006. Ninety-four children were enrolled. Eighty-eight had arterial ischemic stroke and six had sinovenous thrombosis. Twenty-nine percent of the children had seizures. Twenty-six percent had diffuse neurological signs and 76% had focal neurological signs. Risk factors included vascular disease (33%), infection (27%), metabolic disorders (18%), trauma (11%), prothrombotic states (13%), cardiac disease (10%), and mitochondrial disease (6%). Ten percent (n=9) had no identifiable cause. Twenty-two percent of the children had more than one risk factor. Anterior territory (70%) was more involved than posterior territory (18%) in arterial ischemic stroke. Unilateral infarctions were more common on the left side (51%) than on the right (24.5%). Neurological deficits were present in 45% (n=34/75) of the children; the most frequent deficit was motor impairment (24%). Seven children (9%) died in the acute stage. There were 12 children (16%) who had recurrent stroke and 8 children (8/12) who had underlying vascular disease. The vascular disease included moyamoya disease (5), CNS lupus (1) and ill-defined vasculopathy (2). The etiology pattern in Taiwan was different from that in Western countries. Vascular disease was a significant risk factor for recurrence in childhood ischemic stroke.

Age-related variation in presenting signs of childhood arterial ischemic stroke

The objective of this study was to determine whether there are age-related variations in the clinical presentation of cerebral arterial ischemic stroke in children after the perinatal period. We performed a retrospective record review of 76 children with cerebral arterial ischemic stroke occurring between 44 weeks of conceptional age and age 19 years. These children were seen by our pediatric stroke group between September 1, 1989 and August 1, 2005. We examined the following clinical presentations: epileptic seizures, focal weakness, and altered mental status. We compared the frequency of each presentation in children with arterial ischemic stroke up to and after age 1 year. Children aged <1 year were significantly more likely than older children to present with epileptic seizures (45.5% vs 10.8%, P = 0.01) and altered mental status (36.4% vs 7.7%, P = 0.02), and there was a trend for them to be less likely than older children to present with focal weakness (45.5% vs 76.9%, P = 0.06). Children aged <1 year with cerebral arterial ischemic stroke were more likely to present with epileptic seizures and altered mental status than children aged >or=1 year, and may be less likely to present with focal weakness. These findings may aid in the recognition of stroke in young children.

Risk factors for pediatric stroke: consequences for therapy and quality of life

A retrospective population-based study was conducted to calculate incidence of pediatric stroke, detect risk factors, determine long term outcome and to optimize therapy. Patients (age: >1 month and <19 years) with stroke in Vorarlberg, Austria, from 1984-2005 were investigated. Outcome was evaluated in terms of neurological deficits, neuropsychological measures, and quality of life. Consequences on therapy were established according to current guidelines. Twenty-two children, median age 6 years (range, 0.9-14) years, 16 ischemic and 6 hemorrhagic stroke, correspond to an incidence of 1.96 and 0.74/100.000 child-years, respectively. No child died; one had a recurrent stroke. Twenty children (12 boys) were included after a median time of 3.7 years (range, 0.4-18). Risk factors were vasculopathy (17/20; 85%), lipometabolic disorders (17/20; 85%), and prothrombotic abnormality (10/20; 50%). Three children had no risk factor; four children had a reduced quality of life. The study led to therapeutic consequences in 13 of 20 children (65%): aspirin (5/20; 25%), folic acid in (3/20; 15%), and rehabilitative therapy (9/20; 45%). Most children with pediatric stroke have more than one risk factor, mainly vasculopathies or elevation of lipoprotein(a). Overall outcome is determined solely by neurological deficits and is positively influenced by good quality of life.

Diffusion-weighted imaging of the brain in infants and children

During the last decade, diffusion-weighted imaging (DWI) has become an important tool in the evaluation of a variety of disorders of the central nervous system in children. DWI relies on variability in the diffusivity of water molecules in the presence of a supplemental diffusion-sensitizing gradient to produce image contrast. Pathologic states alter the diffusion characteristics of brain water in a reproducible fashion. In this review, the DWI appearances of a number of common abnormalities of the brain in infants and children are presented.

Mimics of childhood stroke: characteristics of a prospective cohort

BACKGROUND

Little is known about the clinical features and spectrum of diagnoses in children with "stroke mimics," those with acute neurologic deficits but without cerebrovascular diseases.

OBJECTIVES

Our goal was to describe patients with stroke mimics and to determine if clinical features predict benign diagnoses.

METHODS

Our stroke consult team registered a prospective consecutive cohort of 143 patients with acute presentations suspicious for cerebrovascular disease from November 2003 to November 2004. Cases in which stroke was ruled out (stroke mimics) were reviewed for clinical features and diagnostic test results and were classified "benign" if there was no structural brain lesion and there was an expectation of complete recovery.

RESULTS

Of the 143 cases evaluated for suspected stroke, 30 (21%) had stroke mimics. Presenting signs included seizure (n = 11), headache (n = 9), mental status change (n = 6), focal weakness (n = 14), and focal sensory change (n = 7). Eleven patients had "benign" diagnoses (3 migraine, 3 psychogenic diagnoses, 3 musculoskeletal abnormalities, 1 delirium, and 1 episodic vital sign changes). Nineteen patients had "not-benign" diagnoses (3 reversible posterior leukoencephalopathy syndrome, 3 neonatal seizures, 2 vascular anomalies, 2 inflammatory disease, 2 intracranial infection, 2 epilepsy, 2 metabolic stroke, 1 tumor, 1 drug toxicity, and 1 idiopathic intracranial hypertension). Except for the presence of seizures, there were no significant differences in presentation or risk factors between benign and not-benign cases.

CONCLUSIONS

Many disorders mimic childhood stroke. History and clinical presentation often do not distinguish the one third of patients with benign disorders from the two thirds with more serious problems, necessitating timely comprehensive investigations, especially brain MRI.

Pediatric stroke: the child is not merely a small adult

Arterial ischemic stroke and sinovenous thrombosis are a significant yet under-recognized causes of mortality and morbidity in the pediatric population. With increasingly complex etiologies yet urgency for rapid diagnosis and treatment, pediatric stroke teams likely will become the standard of care. A common terminology must be developed to avoid confusing types of acute cerebral insults--such as focal arterial ischemic stroke and global hypoxia and ischemia--that have different causes and pathophysiologic mechanisms of injury. Increased awareness of unique pediatric stroke subtypes, their clinical presentation, and their imaging findings will facilitate early identification and development of optimal treatment strategies.

Thrombosis in infants and children

During the last decade much progress has been made toward better understanding of the underlying reasons causing thromboembolism in children. A considerable number of acquired and hereditary thrombotic risk factors have been identified which may also have an impact on therapeutic decisions and prognosis concerning outcome and the risk of a second event. However, indications for therapeutic interventions, such as thrombolysis and prophylactic anticoagulation with respect to the different clinical conditions and their combination with other risk factors, are not yet well defined. The following article describes the causes, clinical presentation and management of thrombosis in neonates, infants and older children, focusing on the clinically most relevant conditions.