Pediatric stroke: past, present and future

Neurological and Functional Outcomes after Pediatric Stroke

Pediatric stroke results in life-long morbidity for many patients, but the outcomes can vary depending on factors such as age of injury, or mechanism, size, and location of stroke. In this review, we summarize the current understanding of outcomes in different neurological domains (eg, motor, cognitive, language) for children with stroke of different mechanisms (ie, arterial ischemic stroke, cerebral sinus venous thrombosis, and hemorrhagic stroke), but with a focus on World Health Organization International Classification for Functioning, Disability, and Health (ICF-CY) framework for measuring health and disability for children and youth. We describe outcomes for the population as a whole and certain factors that may further refine prognostication.

Risk Factors of Pediatric Arterial Ischemic Stroke; A Regional Survey

Background:

Considering that better understanding of the underlying mechanisms and risk factors of arterial ischemic stroke (AIS) would be helpful for better management of stroke and its outcome in children as well as preventing or reducing the occurrence of its related potential disabilities, the aim of this study was to investigate the most common risk factors and causes of AIS in patients referred to the referral hospitals in Tehran and Isfahan cities of Iran.

Methods:

In this study, medical files of all pediatric patients admitted to the Mofid and Imam Hossein children's hospitals with the diagnosis of AIS from 2001 to 2011 and 2011 to 2016, respectively, were evaluated. Identified risk factors of AIS were categorized as arteriopathies, cardiac disorders (CDs), infection, acute head-and-neck disorders, acute systemic conditions, chronic systemic conditions, prothrombotic states, chronic head-and-neck disorders, atherosclerosis-related RFs, and others.

Results:

In this study, 61 patients were evaluated. Mean (standard deviation) age of the patients was 5.1 (3.9) years. About 62.3% of the patients were boys while 37.7% were girls (P < 0.01). A total of 36 patients (59%) had at least one risk factor for AIS. About 40.9% of patients had undetermined risk factors. CDs (21.31%) and vascular disease (21.31%) were the most common risk factors of AIS in the studied children. Nearly 11.5% of the patients had moyamoya vascular disease (MMD).

Conclusion:

The findings of our study indicated that the most common risk factors for AIS in the two studied regions are congenital heart and vascular diseases. The results of the current study could be used for planning more preventive strategies in patients suffering from the mentioned diseases. In addition, the obtained data could be used for conducting targeted education and management of high-risk patients.

Tracking of neurocognitive outcomes over time in children with perinatal stroke and associated complex medical conditions: a case series

Neurocognitive outcomes in children with perinatal stroke are complicated by additional neurological/medical factors. The main objective of this study was to retrospectively examine long-term neurocognitive outcomes in five children with perinatal stroke with increasingly complex comorbidities; ages 5-7 at first evaluation. Results revealed that intelligence and academic skills were significantly decreased in cases with combined perinatal stroke and comorbidities. Early language development was particularly vulnerable to disruption over time in children with increasing medical complexity. The delayed emergence of neurocognitive deficits emphasizes the need for serial assessment of neurocognitive development to identify early services and interventions.

Evaluation of hypercoagulability state in perinatal arterial ischemic stroke with rotation thromboelastometry

BACKGROUND

Perinatal arterial ischemic stroke (PAIS) is an important cause of pediatric morbidity and mortality. The etiology of PAIS remains unknown. Several maternal-neonatal disorders, and especially prothrombotic risk factors, have been reported in infants with perinatal stroke (PS). Rotation thromboelastometry (ROTEM) can analyze the coagulation system, from the beginning of coagulation, through clot formation, and ending with fibrinolysis. The aim of this study was to evaluate the hypercoagulability state in PAIS patients using ROTEM.

METHODS

Patients were obtained by evaluating hospital files retrospectively. Twenty patients with PAIS and 19 healthy controls were included in the study. Prothrombotic risk factors and standard coagulation parameters were collected for all patients. Thromboelastometry (TEM) analysis was performed with the ROTEM® Coagulation Analyzer model Gamma 2500 (Tem International, Munich, Germany). Patients were separated into two groups; Group 1 included PAIS patients with prothrombotic risk factors and Group 2 included patients with no prothrombotic risk factors.

RESULTS

Group 1 includes six patients and Group 2 includes fourteen. Maternal risk factors were reported in 55 % and prothrombotic risk factors were detected in 30 % of the patients. ROTEM analyses were done mean age of 11.2 ± 9.4 months. ROTEM analysis showed that maximum clot firmness (MCF) value on both groups was significantly higher than in the control group, which is consistent with a hypercoagulable state. There was no statistical difference between the MCF values of Group 1 and Group 2. No significant correlations were found between the ROTEM parameters and the hematological parameters.

CONCLUSION

The etiology of PAIS is still unclear. Prothrombotic risk factors may be an important etiology for PAIS. However, standard hematological tests for evaluating prothrombotic risk factors are limited. In our study, ROTEM analyses showed higher maximum clot firmness in PAIS patients compared to controls. ROTEM analyses may suggest a hypercoagulable state due to abnormal fibrinolysis in PAIS patients. Normative data and further research is needed to validate our findings.

Imaging of Pediatric Stroke

Despite being as common as brain tumors in children, lack of awareness of pediatric stroke presents unique challenges, both in terms of diagnosis and management. Due to diverse and overlapping risk factors, as well as variable clinical presentations, the diagnosis can be either missed or frequently delayed. Early recognition and treatment of pediatric stroke is however critical in optimizing long-term functional outcomes, reducing morbidity and mortality, and preventing recurrent stroke. Neuroimaging plays a vital role in achieving this goal. The advancements in imaging over the last two decades have allowed for multiple modality options for suspected stroke with more accurate diagnosis, as well as quicker turnaround time in imaging diagnosis, especially at primary stroke centers. However, with the multiple imaging possibilities, referring physicians can be overwhelmed with the best option for each clinical situation and what the literature recommends. Here the authors review the etiology of pediatric stroke in the settings of arterial ischemia, hemorrhage, and cerebral sinovenous thrombosis (CSVT), with emphasis on the best diagnostic tools available, including advanced imaging techniques.

Considerations in Applying a New Stent Retriever in Pediatric Endovascular Cerebral Thrombectomy for Acute Ischemic Stroke

Acute ischemic stroke (AIS) in children has been difficult to diagnose, treat and study, due to atypical clinical presentation, imaging challenges and the rarity of large-vessel embolic occlusion as the etiology of acute neurological change in children. With endovascular thrombectomy showing success in randomized trials of adult AIS, the technique is increasingly being extrapolated to pediatric stroke. However, there is little evidence regarding the safety or efficacy of applying in children these devices developed and tested in adults. There is concern about a vessel-to-device size mismatch that may result in a different complication and benefit profile than typically seen. We report on the successful application in pediatric stroke of a newer-generation, smaller stent retriever, designed to be delivered through relatively smaller and more navigable microcatheters than the prior generation of this device.

Biochemical and Functional Characterization of RNF213 (Mysterin) R4810K, a Susceptibility Mutation of Moyamoya Disease, in Angiogenesis In Vitro and In Vivo

Background

P.R4810K of RNF213 (mysterin: rs112735431), which is an AAA⁺ ATPase, is the susceptibility polymorphism for moyamoya disease (MMD) in East Asians. However, the role of RNF213 R4810K in the etiology of MMD is unknown.

Methods and Results

To clarify the role of RNF213 in known angiogenic pathways, RNF213 expression was analyzed in endothelial cells (ECs) treated with several angiogenic and antiangiogenic factors, including interferons (IFNs). RNF213 was upregulated by IFN-β through signal transducer and activator of transcription x in the promoter and mediated antiangiogenic activity of IFN-β. RNF213 wild-type (WT) overexpression could not lower angiogenesis without IFN-β, but RNF213 R4810K overexpression could. To correlate biochemical function as ATPase and the role of RNF213 oligomer formation with antiangiogenic activity, we investigated the effects of mutations in the AAA⁺ module. A mutation of the Walker B motif (WEQ), which stabilizes oligomerization, inhibited angiogenesis, but AAA⁺ module deletion, which cannot initiate oligomerization, did not. Intriguingly, R4810K, similar to WEQ, decreased ATPase activity, suggesting its antiangiogenic activity through stabilizing oligomers. To confirm the antiangiogenic effect of RNF213 upregulation in vivo, vascular EC- or smooth muscle cell-specific Rnf213 R4757K (R4810K ortholog) or WT transgenic (Tg) mice were exposed to hypoxia. Cerebral angiogenesis by hypoxia was suppressed in EC-specific Rnf213 R4757K Tg mice, whereas it was not suppressed in other mice.

Conclusions

This study suggests the importance of inflammatory signals as environmental factors and R4810K carriers for susceptibility to cerebral hypoxia. A specific inhibitor of ATP binding to the first AAA⁺ could be a promising therapeutic candidate for MMD.

Determinants of cognitive outcomes of perinatal and childhood stroke: A review

Our understanding of cognitive and behavioral outcomes of perinatal and childhood stroke is rapidly evolving. A current understanding of cognitive outcomes following pediatric stroke can inform prognosis and direct interventions and our understanding of plasticity in the developing brain. However, our understanding of these outcomes has been hampered by the notable heterogeneity that exists amongst the pediatric stroke population, as the influences of various demographic, cognitive, neurological, etiological, and psychosocial variables preclude broad generalizations about outcomes in any one cognitive domain. We therefore aimed to conduct a detailed overview of the published literature regarding the effects of age at stroke, time since stroke, sex, etiology, lesion characteristics (i.e., location, laterality, volume), neurologic impairment, and seizures on cognitive outcomes following pediatric stroke. A key theme arising from this review is the importance of interactive effects among variables on cognitive outcomes following pediatric stroke. Interactions particularly of note include the following: (a) age at Stroke x Lesion Location; (b) Lesion Characteristics (i.e., volume, location) x Neurologic Impairment; (c) Lesion Volume x Time Since Stroke; (d) Sex x Lesion Laterality; and (e) Seizures x Time Since Stroke. Further, it appears that these relationships do not always apply uniformly across cognitive domains but, rather, are contingent upon the cognitive ability in question. Implications for future research directions are discussed.

Surgical management of medically refractory epilepsy due to early childhood stroke

OBJECT.: The risk of developing epilepsy after perinatal stroke, hypoxic/ischemic injury, and intracerebral hemorrhage is significant, and seizures may become medically refractory in approximately 25% of these patients. Surgical management can be difficult due to multilobar or bilateral cortical injury, nonfocal or poorly lateralizing video electroencephalography (EEG) findings, and limited functional reserve. In this study the authors describe the surgical approaches, seizure outcomes, and complications in patients with epilepsy due to vascular etiologies in the perinatal period and early infancy.

METHODS

The records were analyzed of 19 consecutive children and adults with medically refractory epilepsy and evidence of perinatal arterial branch occlusions, hypoxic/ischemic insult, or hemorrhagic strokes, who underwent surgery at the Comprehensive Epilepsy Center of Beth Israel Medical Center and St. Luke's-Roosevelt Hospital Center. Preoperative findings including MRI, video EEG, functional MRI, and neuropsychological testing were analyzed. The majority of patients underwent staged operations with invasive mapping, and all patients had either extra- or intraoperative functional mapping.

RESULTS

In 7 patients with large porencephalic cysts due to major arterial branch occlusions, periinsular functional hemispherotomy was performed in 4 children, and in 3 patients, multilobar resections/disconnections were performed, with 1 patient undergoing additional resections 3 years after initial surgery due to recurrence of seizures. All of these patients have been seizure free (Engel Class IA) after a mean 4.5-year follow-up (range 15-77 months). Another 8 patients had intervascular border-zone ischemic infarcts and encephalomalacia, and in this cohort 2 hemispherotomies, 5 multilobar resections/disconnections, and 1 focal cortical resection were performed. Seven of these patients remain seizure free (Engel Class IA) after a mean 4.5-year follow-up (range 9-94 months), and 1 patient suffered a single seizure after 2.5 years of seizure freedom (Engel Class IB, 33-month follow-up). In the final 4 patients with vascular malformation-associated hemorrhagic or ischemic infarction in the perinatal period, a hemispherotomy was performed in 1 case, multilobar resections in 2 cases, and in 1 patient a partial temporal lobectomy was performed, followed 6 months later by a complete temporal and occipital lobectomy due to ongoing seizures. All of these patients have had seizure freedom (Engel Class IA) with a mean follow-up of 4.5 years (range 10-80 months). Complications included transient monoparesis or hemiparesis in 3 patients, transient mutism in 1 patient, infection in 1 patient, and a single case of permanent distal lower-extremity weakness. Transient mood disorders (depression and anxiety) were observed in 2 patients and required medical/therapeutic intervention.

CONCLUSIONS

Epilepsy surgery is effective in controlling medically intractable seizures after perinatal vascular insults. Seizure foci tend to be widespread and rarely limited to the area of injury identified through neuroimaging, with invasive monitoring directing multilobar resections in many cases. Long-term functional outcomes have been good in these patients, with significant improvements in independence, quality of life, cognitive development, and motor skills, despite transient postoperative monoparesis or hemiparesis and occasional mood disorders.

[Current management of post-varicella stroke in children: a literature review]

Among infectious factors, varicella-zoster virus (VZV) is a leading cause of central nervous system vasculopathy and stroke in childhood. Not only have viral markers been detected in the cerebrospinal fluid of affected patients, but also direct evidence of viral particles in the wall of cerebral arteries has been demonstrated in rare pathological specimens. This certainly reflects a localized infectious process likely associated with variable indirect inflammatory responses. Yet the usefulness in this setting of a lumbar puncture as well as of subsequent targeted antiviral and/or anti-inflammatory therapies is uncertain. Indeed, in the majority of cases, the so-called post-varicella angiopathy has a monophasic evolution with spontaneous resolution or stabilization, explaining diverging diagnostic and treatment approaches. In this paper, we have addressed this problematic area by reviewing 26 published cases from the year 2000 and three unpublished cases. Post-varicella stroke is typically associated with angiopathy most often involving the initial portion of the middle cerebral artery, causing a basal ganglia stroke. It tends to occur in young immunocompetent children. Thrombophilia work-up is in general negative. Lumbar puncture was performed in 17 out of 29 cases. Viral markers were examined in 14 cases, but were positive in only eight cases. Antiviral therapy was administrated in 11 children. In this small retrospective study, the treated children's vasculopathy did not progress more favorably nor was there a better outcome compared with untreated subjects.

Risk factors and clinical outcomes of childhood ischemic stroke in a single Korean tertiary care center

A 10-year, retrospective review of the risk factors and clinical outcome of childhood ischemic stroke treated in a single tertiary care center was conducted. Sixty-two children were identified (33 boys and 29 girls), ages 1 month to 17 years. Risk factors included vasculopathy (35.5%), cardiac disease (17.4%), metabolic disorder (14.5%), infection (14.5%), and coagulopathy (1.6%). Nine patients (14.5%) had no identifiable cause of stroke and 1 patient had 2 risk factors. Hemiplegia (69.3%) and seizures (32.3%) were the most common presenting features, and seizures were significantly more frequent in children <12 months of age than in older children (71.4% vs 20.8%, P = .001). Recurrence of stroke occurred in 55.6% of patients with metabolic disorder, 33.3% of those with cardiac disease, and 19.0% of those with vasculopathy. Vasculopathy including moyamoya disease was the most important risk factor for ischemic stroke in Korea, and their prognosis were varied with the etiology of stroke.

Baby STEPS: a giant leap for cell therapy in neonatal brain injury

We advance Baby STEPS or Stem cell Therapeutics as an Emerging Paradigm in Stroke as a guide in facilitating the critical evaluation in the laboratory of the safety and efficacy of cell therapy for neonatal encephalopathy. The need to carefully consider the clinical relevance of the animal models in mimicking human neonatal brain injury, selection of the optimal stem cell donor, and the application of functional outcome assays in small and large animal models serve as the foundation for preclinical work and beginning to understand the mechanism of this cellular therapy. The preclinical studies will aid our formulation of a rigorous human clinical trial that encompasses not only efficacy testing but also monitoring of safety indices and demonstration of mechanisms of action. This schema forms the basis of Baby STEPS. Our goal is to resonate the urgent call to enhance the successful translation of cell therapy from the laboratory to the clinic.

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.