Risk Factors, Clinical Presentation, and Neuroimaging Findings of Neonatal Perforator Stroke

Perinatal Stroke in a Chinese Neonatal Center: Clinical Characteristics, Long-Term Outcomes, and Prognostic Factors

BACKGROUND

Neonatal stroke manifests atypically and can potentially result in significant neurological sequelae in affected infants. Studies on long-term neurodevelopmental outcomes and prognostic factors are limited. We aimed to assess the clinical characteristics, long-term outcomes, and prognostic factors of perinatal stroke.

METHODS

Patients diagnosed with perinatal stroke were enrolled from 2009 to 2018. Clinical data including general information, clinical manifestations, and risk factors were collected and compared. Follow-up was performed for at least two years. Statistical analysis was performed using the chi-square test, t tests, and logistic regression analysis.

RESULTS

Sixty-nine cases were identified with an incidence of one of 2049 live births (51 boys and 18 girls). Twenty-seven patients (39%) experienced perinatal ischemic stroke (PIS) and 42 (61%) perinatal hemorrhagic stroke (PHS). In 48 cases (69%) onset involved acute symptomatic stroke (21 ischemic strokes and 27 hemorrhagic strokes). Seizures within 12 to 72 hours (20 cases, 29%) were the most common presentations. Most (57%) perinatal arterial ischemic strokes focused on the left middle cerebral artery. About 43% of PHS was diagnosed with temporal lobe hemorrhage, and 40% of patients exhibited multiple lesions of cerebral parenchymal hemorrhage. There was no association between adverse prognosis after perinatal stroke and different risk factors. During follow-up, six patients (10%) were dead and 22 patients (35%) experienced adverse neurodevelopmental outcomes.

CONCLUSIONS

More infants exhibited hemorrhagic stroke than ischemic stroke. Among infants with asymptomatic perinatal stroke, PHS was more common. The first symptom of perinatal stroke within 12 to 72 hours after birth is convulsions, with the left middle cerebral artery and the temporal lobe being the most common lesion sites for ischemic and hemorrhagic strokes, respectively. PIS was more likely to achieve adverse outcomes.

Neonatal Arterial Ischaemic Stroke: Advances in Pathologic Neural Death, Diagnosis, Treatment, and Prognosis

Neonatal arterial ischaemic stroke (NAIS) is caused by focal arterial occlusion and often leads to severe neurological sequelae. Neural deaths after NAIS mainly include necrosis, apoptosis, necroptosis, autophagy, ferroptosis, and pyroptosis. These neural deaths are mainly caused by upstream stimulations, including excitotoxicity, oxidative stress, inflammation, and death receptor pathways. The current clinical approaches to managing NAIS mainly focus on supportive treatments, including seizure control and anticoagulation. In recent years, research on the pathology, early diagnosis, and potential therapeutic targets of NAIS has progressed. In this review, we summarise the latest progress of research on the pathology, diagnosis, treatment, and prognosis of NAIS and highlight newly potential diagnostic and treatment approaches.

Perinatal Stroke in Fetuses, Preterm and Term Infants

Perinatal stroke is a well-defined heterogenous group of disorders involving a focal disruption of cerebral blood flow between 20 weeks gestation and 28 days of postnatal life. The most focused lifetime risk for stroke occurs during the first week after birth. The morbidity of perinatal stroke is high, as it is the most common cause of hemiparetic cerebral palsy which results in lifelong disability that becomes more apparent throughout childhood. Perinatal strokes can be classified by the timing of diagnosis (acute or retrospective), vessel involved (arterial or venous), and underlying cause (hemorrhagic or ischemic). Perinatal stroke has primarily been reported as a disorder of term infants; however, the preterm brain possesses different vulnerabilities that predispose an infant to stroke injury both in utero and after birth. Accurate diagnosis of perinatal stroke syndromes has important implications for investigations, management, and prognosis. The classification of perinatal stroke by age at presentation (fetal, preterm neonatal, term neonatal, and infancy/childhood) is summarized in this review, and includes detailed descriptions of risk factors, diagnosis, treatment, outcomes, controversies, and resources for family support.

Neonatal stroke in premature neonates

There are many neuro-imaging studies on the presence of brain lesions in the preterm infant, using cranial ultrasound (cUS) and/or term equivalent age MRI (TEA-MRI). These studies however tend to focus on germinal matrix-intraventricular hemorrhage (GMH-IVH) and white matter injury. Data about perinatal arterial ischemic stroke (PAIS) or cerebral sinovenous thrombosis (CSVT) in the preterm infant are very limited. In fact, several large cohort studies on neuro-imaging in preterm infants do not even mention neonatal stroke.^1-4 Most studies about PAIS exclude preterm infants.⁵ The aim of this review was to provide an update on neonatal stroke in the preterm infant, with a focus on neuro-imaging findings.

Epidemiology and pathogenesis of stroke in preterm infants: A systematic review

BACKGROUND:

Perinatal stroke is one of the principal causes of cerebral palsy (CP) in preterm infants. Stroke in preterm infants is different from stroke in term infants, given the differences in brain maturation and the mechanisms of injury exclusive to the immature brain. We conducted a systematic review to explore the epidemiology and pathogenesis of periventricular hemorrhagic infarction (PVHI), perinatal arterial ischemic stroke (PAIS) and cerebral sinovenous thrombosis (CSVT) in preterm infants.

METHODS:

Studies were identified based on predefined study criteria from MEDLINE, EMBASE, SCOPUS and WEB OF SCIENCE electronic databases from 2000 –2019. Results were combined using descriptive statistics.

RESULTS:

Fourteen studies encompassed 546 stroke cases in preterm infants between 23 –36 weeks gestational ages and birth weights between 450 –3500 grams. Eighty percent (436/546) of the stroke cases were PVHI, 17%(93/546) were PAIS and 3%(17/546) were CSVT. Parietal PVHI was more common than temporal and frontal lobe PVHI. For PAIS, left middle cerebral artery (MCA) was more common than right MCA or cerebellar stroke. For CSVT partial or complete thrombosis in the transverse sinus was universal. All cases included multiple possible risk factors, but the data were discordant precluding aggregation within a meta-analysis.

CONCLUSION:

This systematic review confirms paucity of data regarding the etiology and the precise causal pathway of stroke in preterm infants. Moreover, the preterm infants unlike the term infants do not typically present with seizures. Hence high index of clinical suspicion and routine cUS will assist in the timely diagnosis and understanding of stroke in this population.

Clinico-Epidemiological Profile, Etiology, and Imaging in Neonatal Stroke: An Observational Study from Eastern India

Aim

The aim of this study was to assess the clinico-epidemiological profile, etiology, and imaging findings in neonatal stroke (NS).

Materials and Methods

This was a retrospective, observational study on neonates presenting with stroke between August 2014 and July 2016 to a tertiary care hospital in eastern India.

Results

In all, 43 neonates were analyzed, with a male-to-female ratio of 2.3:1. About 88% babies were born at term and the rest were preterm. In 37%, the etiology of stroke was related to hypoxic injury, 21% had sepsis, and 35% had idiopathic causes. Seizures were the most common mode of presentation (62%) followed by poor feeding, abnormal tone, recurrent apnea, encephalopathy, and hemiparesis. There was an almost equal prevalence of ischemic stroke (53%) and hemorrhagic stroke (HS). Middle cerebral artery territory was the primary site of involvement in arterial ischemic stroke, and intra ventricular hemorrhage was the most common presentation of HS.

Conclusion

NS is an acute emergency with high morbidity and mortality. Magnetic resonance imaging helps in diagnosis and prognostication in the absence or paucity of focal neurological signs in neonates.

Perinatal stroke

Perinatal stroke is a heterogeneous syndrome resulting from brain injury of vascular origin that occurs between 20 weeks of gestation and 28 days of postnatal life. The incidence of perinatal stroke is estimated to be between 1:1600 and 1:3000 live births (approximately 2500 children per year in the United States), though its actual incidence is difficult to estimate because it is likely underdiagnosed. Perinatal arterial ischemic stroke (PAIS) accounts for approximately 70% of cases of perinatal stroke. Cerebral sinovenous thrombosis, while less common, also accounts for a large proportion of the morbidity and mortality seen with perinatal stroke. Hemorrhagic stroke leads to disruption of neurologic function due to intracerebral hemorrhage that is nontraumatic in origin. While most cases of PAIS fall into one of these three categories, other patterns of injury should also be considered perinatal stroke. In some cases, the etiology of PAIS is not known but is idiopathic. This chapter will review the classification, risk factors, pathogenesis, clinical presentation, management, and long-term sequelae of perinatal stroke.

Perinatal stroke syndromes: Similarities and diversities in aetiology, outcome and management

With a birth-prevalence of 37-67/100,000 (mostly term-born), perinatal stroke encompasses distinct disease-states with diverse causality, mechanism, time of onset, mode of presentation and outcome. Neonatal primary haemorrhagic stroke and ischemic events (also divided into neonatal arterial ischemic stroke and neonatal cerebral sinus venous thrombosis) that manifest soon after birth are distinguished from presumed perinatal - ischemic or haemorrhagic - stroke. Signs of the latter become apparent only beyond the neonatal period, most often with motor asymmetry or milestones delay, and occasionally with seizures. Acute or remote MRI defines the type of stroke and is useful for prognosis. Acute care relies on homeostatic maintenance. Seizures are often self-limited and anticonvulsant agents might be discontinued before discharge. Prolonged anticoagulation for a few weeks is an option in some cases of sinovenous thrombosis. Although the risk of severe impairment is low, many children develop mild to moderate multimodal developmental issues that require a multidisciplinary approach.

Perinatal arterial ischemic stroke

Perinatal arterial ischemic stroke is a relatively common and serious neurologic disorder that can affect the fetus, the preterm, and the term-born infant. It carries significant long-term disabilities. Herein we describe the current understanding of its etiology, pathophysiology and classification, different presentations, and optimal early management. We discuss the role of different brain imaging modalities in defining the extent of lesions and the impact this has on the prediction of outcomes. In recent years there has been progress in treatments, making early diagnosis and the understanding of likely morbidities imperative. An overview is given of the range of possible outcomes and optimal approaches to follow-up and support for the child and their family in the light of present knowledge.

[Neonatal arterial ischemic stroke in term or near-term newborns: prevalence and risk factors]

The general designation ischemic perinatal stroke includes several disease states that differ in pathophysiology, timing of occurrence and presentation. While it seems logical to assume that their prevalence and their risk factors depend primarily on the considered type of stroke, most studies used inconsistent definitions or included heterogeneous populations, which limits their accuracy. Given these biases, the French Society of Neonatology and the French Centre for Paediatric Stroke wished to update the knowledge in this domain, focusing on a specific form of perinatal stroke, i.e neonatal arterial ischemic stroke (NAIS) in term or near term newborns. A comprehensive analysis of published epidemiological data was dedicated to the following issues: Is the prevalence of NAIS well defined from epidemiological studies? What are the best recognized risk factors and is it possible to delineate a maternal and fetal population at risk for this condition? On July 31, 2015 a total of four hospitalized-based and five population-based studies, and six case-control studies were found. The conclusions are the following: The prevalence of NAIS in term or near term newborns varies from 6 to 17/100,000 live births (level of evidence 2). NAIS represents a half of total ischemic perinatal strokes (i.e. including those with delayed presentation as well) and one fourth of perinatal strokes (i.e. including cerebral haemorrhage stroke as well). Four sets of risk factors are consistent across different studies (level of evidence 3): (1) male sex, (2) obstetrical determinants (first pregnancy, caesarean section), and two peripartum complications: (3) intrapartum hypoxia and (4) materno-fetal/neonatal infection. Bacterial meningitis, cardiac disorders/procedures and invasive care such as extra-corporeal circulation carry a risk of NAIS as well. A registry could help refining epidemiological descriptive data. It could also be used to develop etiological studies focusing on pathophysiological hypotheses derived from the identified aforementioned risk factors.

Placental Pathology in Neonatal Stroke: A Retrospective Case-Control Study

OBJECTIVE

To assess the association of placental abnormalities with neonatal stroke.

STUDY DESIGN

This retrospective case-control study at 3 academic medical centers examined placental specimens for 46 children with neonatal arterial or venous ischemic stroke and 99 control children without stroke, using a standard protocol. Between-group comparisons used χ² and Fisher exact t test. Correlations used Spearman correlation coefficient.

RESULTS

Case placentas were more likely than controls to meet criteria for ≥1 of 5 major categories of pathologic abnormality (89% vs 62%; OR, 5.1; 95% CI, 1.9-14.0; P = .0007) and for ≥2 categories (38% vs 8%; OR, 7.3; 95% CI, 2.9-19.0; P < .0001). Fetal vascular malperfusion occurred in 50% of cases and 17% of controls (OR, 4.8; 95% CI, 2.2-10.5; P = .0001). Amniotic fluid inflammation occurred in 46% of cases with arterial ischemic stroke vs 25% of controls (OR, 2.6; 95% CI, 1.1-6.1; P = .037). There was evidence of a "stress response" (meconium plus elevated nucleated red blood cells) in 24% of cases compared with 1% of controls (OR, 31; 95% CI, 3.8-247.0; P < .0001).

CONCLUSIONS

Placental abnormality was more common in children with neonatal stroke compared with controls. All placental findings represent subacute-to-chronic intrauterine stressors. Placental thrombotic processes were associated with both arterial and venous stroke. Our findings provide evidence for specific mechanisms that may predispose to acute perinatal stroke. Amniotic fluid inflammation associated with neonatal arterial ischemic stroke deserves further investigation.

[Recommendations for imaging neonatal ischemic stroke]

Neuroimaging is critical for the diagnosis of neonatal arterial ischemic stroke (NAIS) and for prognosis estimation. The purpose of this work is to define guidelines of clinical neuroimaging for the diagnosis of NAIS, for the optimization of the imaging timing and for the assessment of the prognostic value of each imaging technique. A systematic search of electronic databases (Medline via Pubmed) for studies whose title and abstract were focused on NAIS has been conducted. One hundred and ten articles were selected and their results were analyzed by three Senior Practitioners of pediatric radiology using common methodology for guidelines elaboration within the group of experts gathered by Scientific Societies in the field. MRI with a diffu si on-weighted sequence (DWI) and T1, T2, and T2*-weighted sequences must be performed in the case of suspected NAIS (no sedation is required). In the first hours after the injury, an acute ischemic lesion is characterized by a hypersignal on the diffusion-weighted sequence, with a decrease of the apparent coefficient of diffusion (ADC). The best time to evaluate the extent of the ischemic lesion is between day 2 and day 4 after injury, when the ADC decrease reaches its nadir. In the acute phase, US may be useful as first imaging at the bedside to exclude other pathologies like large space-occupying hemorrhages, but its specific added value on NAIS diagnosis or prognosis assessment is very low. CT scan has no added value in NAIS, compared to MRI. Motor outcome is correlated with the extent of the lesion and with the presence of a definite injury of the corticospinal tract, which is well seen on the diffusion sequence at the acute stage. A secondary atrophy within the mesencephalon (cerebral peduncles) is tied in with a high risk of hemiplegia. Visual outcome is more often compromised in the case of lesions of the posterior cerebral artery territory.

Pediatric arterial ischemic stroke: Epidemiology, risk factors, and management

Pediatric arterial ischemic stroke (AIS) is an uncommon but important cause of neurologic morbidity in neonates and children, with consequences including hemiparesis, intellectual disabilities, and epilepsy. The causes of pediatric AIS are unique to those typically associated with stroke in adults. Familiarity with the risk factors for AIS in children will help with efficient diagnosis, which is unfortunately frequently delayed. Here we review the epidemiology and risk factors for AIS in neonates and children. We also outline consensus-based practices in the evaluation and management of pediatric AIS. Finally we discuss the outcomes observed in this population. While much has been learned in recent decades, many uncertainties sill persist in regard to pediatric AIS. The ongoing development of specialized centers and investigators dedicated to pediatric stroke will continue to answer such questions and improve our ability to effectively care for these patients.

Neurodevelopmental outcome after neonatal perforator stroke

AIM

To assess outcome after neonatal perforator stroke in the largest cohort to date.

METHOD

Survivors from a cohort of children diagnosed with neonatal perforator stroke using cranial ultrasound or magnetic resonance imaging were eligible for inclusion. Recovery and Recurrence Questionnaire score, presence of cerebral palsy (CP), and crude outcome were assessed, specifically (1) the ability to walk independently, (2) participation in regular education, and (3) the presence of epilepsy.

RESULTS

Thirty-seven patients (20 males, 17 females) aged 3 to 14 years (mean age 8y) were included in the study: 14 with isolated single perforator stroke, four with multiple isolated perforator strokes, and 19 with additional brain injury. Out of 18 children with isolated perforator stroke(s), four had CP, one could not walk independently, and one developed epilepsy. The posterior limb of the internal capsule was involved in four out of 18 patients; three of these patients had CP. Of 19 children with additional brain injury, 11 had CP and three were not able to walk independently. Three out of nine children with concomitant cortical middle cerebral artery stroke developed epilepsy.

INTERPRETATION

Perforator stroke patterns can be of use in predicting long-term outcome and for guiding counselling and surveillance. Motor outcome was favourable in children with isolated perforator stroke(s), except when the posterior limb of the internal capsule was involved.

Long term motor function after neonatal stroke: Lesion localization above all

Motor outcome is variable following neonatal arterial ischemic stroke (NAIS). We analyzed the relationship between lesion characteristics on brain MRI and motor function in children who had suffered from NAIS. Thirty eight full term born children with unilateral NAIS were investigated at the age of seven. 3D T1- and 3D FLAIR-weighted MR images were acquired on a 3T MRI scanner. Lesion characteristics were compared between patients with and without cerebral palsy (CP) using the following approaches: lesion localization either using a category-based analysis, lesion mapping as well as voxel-based lesion-symptom mapping (VLSM). Using diffusion-weighted imaging the microstructure of the cortico-spinal tract (CST) was related to the status of CP by measuring DTI parameters. Whereas children with lesions sparing the primary motor system did not develop CP, CP was always present when extensive lesions damaged at least two brain structures involving the motor system. The VLSM approach provided a statistical map that confirmed the cortical lesions in the primary motor system and revealed that CP was highly correlated with lesions in close proximity to the CST. In children with CP, diffusion parameters indicated microstructural changes in the CST at the level of internal capsule and the centrum semiovale. White matter damage of the CST in centrum semiovale was a highly reproducible marker of CP. This is the first description of the implication of this latter region in motor impairment after NAIS. In conclusion, CP in childhood was closely linked to the location of the infarct in the motor system.

Imaging the premature brain: ultrasound or MRI?

Neuroimaging of preterm infants has become part of routine clinical care, but the question is often raised on how often cranial ultrasound should be done and whether every high risk preterm infant should at least have one MRI during the neonatal period. An increasing number of centres perform an MRI either at discharge or around term equivalent age, and a few centres have access to a magnet in or adjacent to the neonatal intensive care unit and are doing sequential MRIs. In this review, we try to discuss when best to perform these two neuroimaging techniques and the additional information each technique may provide.