Indications for cerebral revascularization for moyamoya syndrome in pediatric sickle cell disease determined by Delphi methodology.

OBJECTIVE: Cerebral revascularization surgery (CRS) has been used to prevent stroke in children with sickle cell disease (SCD) and cerebral vasculopathy (e.g., moyamoya syndrome). While results suggest that it may be an effective treatment, surgical indications have not been well defined. This study sought to determine indications for offering revascularization surgery in centers with established sickle cell programs in the US. METHODS: Three sequential surveys utilizing the Delphi methodology were administered to neurosurgeons participating in the Stroke in Sickle Cell Revascularization Surgery study. Respondents were presented with clinical scenarios of patients with SCD and varying degrees of ischemic presentation and vasculopathy, and the group's agreement to offer surgical revascularization was measured. Consensus was defined as ≥ 75% similar responses. RESULTS: The response rate to all 3 surveys was 100%. Seventeen neurosurgeons from 16 different centers participated. The presence of moyamoya collaterals (MMCs) and arterial stenosis matching an ischemic distribution yielded the strongest recommendations to offer surgery. There was consensus to offer revascularization in the presence of MMCs and at least 50% arterial stenosis matching an ischemic distribution. In contrast, there was no consensus to offer revascularization with 50%-70% stenosis not matching an ischemic presentation in the absence of MMCs. The presence of the ivy sign in the distribution of the stenotic artery also contributed to the consensus to offer surgery in certain scenarios. CONCLUSIONS: There were several clinical scenarios that attained consensus to offer surgery; the strongest was moderate to severe arterial stenosis that matched the distribution of ischemic presentation in the presence of MMCs. Radiological findings of decreased cerebral flow or perfusion also facilitated attaining consensus to offer surgery. The findings of this study reflect expert opinion about questions that deserve prospective clinical research. Determination of indications for CRS can guide clinical practice and aid the design of prospective studies.

Current Practice: Rationale for Screening Children with Hereditary Hemorrhagic Telangiectasia for Brain Vascular Malformations.

BACKGROUND: Hereditary hemorrhagic telangiectasia is an autosomal dominant vascular dysplasia characterized by mucocutaneous telangiectasias, recurrent epistaxis, and organ vascular malformations including in the brain, which occur in about 10% of patients. These brain vascular malformations include high-flow AVMs and AVFs as well as low-flow capillary malformations. High-flow lesions can rupture, causing neurologic morbidity and mortality. STATE OF PRACTICE: International guidelines for the diagnosis and management of hereditary hemorrhagic telangiectasia recommend screening children for brain vascular malformations with contrast enhanced MR imaging at hereditary hemorrhagic telangiectasia diagnosis. Screening has not been uniformly adopted by some practitioners who contend that screening is not justified. Arguments against screening include application of short-term data from the adult A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA) trial of unruptured sporadic brain AVMs to children with hereditary hemorrhagic telangiectasia as well as concerns about administration of sedation or IV contrast and causing patients or families increased anxiety. ANALYSIS: In this article, a multidisciplinary group of experts on hereditary hemorrhagic telangiectasia reviewed data that support screening guidelines and counter arguments against screening. Children with hereditary hemorrhagic telangiectasia have a preponderance of high-flow lesions including AVFs, which have the highest rupture risk. The rupture risk among children is estimated at about 0.7% per lesion per year and is additive across lesions and during a lifetime. ARUBA, an adult clinical trial of expectant medical management versus treatment of unruptured brain AVMs, favored medical management at 5 years but is not applicable to pediatric patients with hereditary hemorrhagic telangiectasia given the life expectancy of a child. Additionally, interventional, radiosurgical, and surgical techniques have improved with time. Experienced neurovascular experts can prospectively determine the best treatment for each child on the basis of local resources. The "watch and wait" approach to imaging means that children with brain vascular malformations will not be identified until a potentially life-threatening and deficit-producing intracerebral hemorrhage occurs. This expert group does not deem this to be an acceptable trade-off.

Pediatric Moyamoya Revascularization Perioperative Care: A Modified Delphi Study.

BACKGROUND: Surgical revascularization decreases the long-term risk of stroke in children with moyamoya arteriopathy but can be associated with an increased risk of stroke during the perioperative period. Evidence-based approaches to optimize perioperative management are limited and practice varies widely. Using a modified Delphi process, we sought to establish expert consensus on key components of the perioperative care of children with moyamoya undergoing indirect revascularization surgery and identify areas of equipoise to define future research priorities. METHODS: Thirty neurologists, neurosurgeons, and intensivists practicing in North America with expertise in the management of pediatric moyamoya were invited to participate in a three-round, modified Delphi process consisting of a 138-item practice patterns survey, anonymous electronic evaluation of 88 consensus statements on a 5-point Likert scale, and a virtual group meeting during which statements were discussed, revised, and reassessed. Consensus was defined as ≥ 80% agreement or disagreement. RESULTS: Thirty-nine statements regarding perioperative pediatric moyamoya care for indirect revascularization surgery reached consensus. Salient areas of consensus included the following: (1) children at a high risk for stroke and those with sickle cell disease should be preadmitted prior to indirect revascularization; (2) intravenous isotonic fluids should be administered in all patients for at least 4 h before and 24 h after surgery; (3) aspirin should not be discontinued in the immediate preoperative and postoperative periods; (4) arterial lines for blood pressure monitoring should be continued for at least 24 h after surgery and until active interventions to achieve blood pressure goals are not needed; (5) postoperative care should include hourly vital signs for at least 24 h, hourly neurologic assessments for at least 12 h, adequate pain control, maintaining normoxia and normothermia, and avoiding hypotension; and (6) intravenous fluid bolus administration should be considered the first-line intervention for new focal neurologic deficits following indirect revascularization surgery. CONCLUSIONS: In the absence of data supporting specific care practices before and after indirect revascularization surgery in children with moyamoya, this Delphi process defined areas of consensus among neurosurgeons, neurologists, and intensivists with moyamoya expertise. Research priorities identified include determining the role of continuous electroencephalography in postoperative moyamoya care, optimal perioperative blood pressure and hemoglobin targets, and the role of supplemental oxygen for treatment of suspected postoperative ischemia.

Characteristics of Moyamoya Syndrome in Pediatric Patients With Neurofibromatosis Type 1.

BACKGROUND: Moyamoya syndrome (MMS) is a progressive cerebral arteriopathy with increased incidence in children with neurofibromatosis type 1 (NF1). Despite the potential for significant neurological morbidity including stroke, little is known about the natural history, and no guidelines exist for screening and management of NF1-associated MMS. METHODS: We identified 152 literature cases of children aged ≤18 years with NF1-associated MMS. A meta-analysis was performed evaluating clinical and neuroimaging findings and patient outcomes. Data from 19 patients with NF1-associated MMS from our center treated from January 1995 to July 2020 were abstracted via chart review and similarly analyzed for clinical and neuroimaging features. RESULTS: Meta-analysis of literature cases showed a median age of MMS diagnosis of 6 years (interquartile range 3 to 10.8 years). Optic pathway gliomas were more common in patients with MMS (42%) compared with historical prevalence. Stroke or transient ischemic attack (TIA) was present at diagnosis in 46%. TIA and stroke were more common in patients with bilateral versus unilateral MMS (62% vs 34%, P = 0.001) and in children aged <4 years versus those aged ≥4 years (61% vs 40%, P = 0.02). Compared with the literature cases, our cohort was more frequently asymptomatic (42% vs 25%) and less likely to present with TIA or stroke (32% vs 46%) at diagnosis. CONCLUSIONS: These data suggest there is an aggressive form of MMS in children with NF1 <4 years of age. Therefore, early screening should be considered to facilitate early detection and treatment of cerebral arteriopathy.

Neurocognitive outcomes of children with non-syndromic single-suture craniosynostosis.

While the focus of craniosynostosis surgery is to improve head shape, neurocognitive sequelae are common and are incompletely understood. Neurodevelopmental problems that children with craniosynostosis face include cognitive and language impairments, motor delays or deficits, learning disabilities, executive dysfunction, and behavioral problems. Studies have shown that children with multiple suture craniosynostosis have more impairment than children with single-suture craniosynostosis. Children with isolated single-suture subtypes of craniosynostosis such as sagittal, metopic, and unicoronal craniosynostosis can have distinct neurocognitive profiles. In this review, we discuss the unique neurodevelopmental profiles of children with single-suture subtypes of craniosynostosis.

Arterial spin labeling as an ancillary assessment to postoperative conventional angiogram in pediatric moyamoya disease.

OBJECTIVE: Digital subtraction angiography (DSA) is commonly performed after pial synangiosis surgery for pediatric moyamoya disease to assess the degree of neovascularization. However, angiography is invasive, and the risk of ionizing radiation is a concern in children. In this study, the authors aimed to identify whether arterial spin labeling (ASL) can predict postoperative angiogram grading. In addition, they sought to determine whether patients who underwent ASL imaging without DSA had similar postoperative outcomes when compared with patients who received ASL imaging and postoperative DSA. METHODS: The medical records of pediatric patients who underwent pial synangiosis for moyamoya disease at a quaternary children's hospital were reviewed during a 10-year period. ASL-only and ASL+DSA cohorts were analyzed. The frequency of preoperative and postoperative symptoms was analyzed within each cohort. Three neuroradiologists assigned a visual ASL grade for each patient indicating the change from the preoperative to postoperative ASL perfusion sequences. A postoperative neovascularization grade was also assigned for patients who underwent DSA. RESULTS: Overall, 21 hemispheres of 14 patients with ASL only and 14 hemispheres of 8 patients with ASL+DSA were analyzed. The groups had similar rates of MRI evidence of acute or chronic stroke preoperatively (61.9% in the ASL-only group and 64.3% in the ASL+DSA group). In the entire cohort, transient ischemic attack (TIA) (p = 0.027), TIA composite (TIA or unexplained neurological symptoms; p = 0.0006), chronic headaches (p = 0.035), aphasia (p = 0.019), and weakness (p = 0.001) all had decreased frequency after intervention. The authors found a positive association between revascularization observed on DSA and the visual ASL grading (p = 0.048). The visual ASL grades in patients with an angiogram indicating robust neovascularization demonstrated improved perfusion when compared with the ASL grades of patients with a poor neovascularization. CONCLUSIONS: Noninvasive ASL perfusion imaging had an association with postoperative DSA neoangiogenesis following pial synangiosis surgery in children. There were no significant postoperative stroke differences between the ASL-only and ASL+DSA cohorts. Both cohorts demonstrated significant improvement in preoperative symptoms after surgery. Further study in larger cohorts is necessary to determine whether the results of this study are validated in order to circumvent the invasive catheter angiogram.

Association of Pediatric ASPECTS and NIH Stroke Scale, Hemorrhagic Transformation, and 12-Month Outcome in Children With Acute Ischemic Stroke.

OBJECTIVE: We aimed to determine whether a modified pediatric Alberta Stroke Program Early CT Score (modASPECTS) is associated with clinical stroke severity, hemorrhagic transformation, and 12-month functional outcomes in children with acute AIS. METHODS: Children (29 days to <18 years) with acute AIS enrolled in two institutional prospective stroke registries at Children's Hospital of Philadelphia and Royal Children's Hospital Melbourne, Australia were retrospectively analyzed to determine whether modASPECTS, in which higher scores are worse, correlated with acute Pediatric NIH Stroke Scale (PedNIHSS) scores (children ≥2 years of age), was associated with hemorrhagic transformation on acute MRI, and correlated with 12-month functional outcome on the Pediatric Stroke Outcome Measure (PSOM). RESULTS: 131 children were included; 91 were ≥2 years of age. Median days from stroke to MRI was 1 (interquartile range [IQR] 0-1). Median modASPECTS was 4 (IQR 3-7). ModASPECTS correlated with PedNIHSS (rho=0.40, P=0.0001). ModASPECTS was associated with hemorrhagic transformation (OR 1.13 95% CI 1.02-1.25, P=0.018). Among children with follow-up (N=128, median 12.2 months, IQR 9.5-15.4 months), worse outcomes were associated with higher modASPECTS (common OR 1.14, 95%CI 1.04-1.24, P=0.005). The association between modASPECTS and outcome persisted when we adjusted for age at stroke ictus and the presence of tumor or meningitis as stroke risk factors (common OR 1.14, 95%CI 1.03-1.25, P=0.008). CONCLUSIONS: ModASPECTS correlates with PedNIHSS scores, hemorrhagic transformation, and 12-month functional outcome in children with acute AIS. Future pediatric studies should evaluate its usefulness in predicting symptomatic intracranial hemorrhage and outcome after acute revascularization therapies. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that the modified pediatric ASPECTS on MRI is associated with stroke severity (as measured by the baseline pediatric NIH Stroke Scale), hemorrhagic transformation, and 12-month outcome in children with acute supratentorial ischemic stroke.

Cancer and Tumor-Associated Childhood Stroke: Results From the International Pediatric Stroke Study.

BACKGROUND: The prevalence of cancer among children with stroke is unknown. This study sought to evaluate cancer- and tumor-associated childhood ischemic stroke in a multinational pediatric stroke registry. METHODS: Children aged 29 days to less than 19 years with arterial ischemic stroke or cerebral sinovenous thrombosis enrolled in the International Pediatric Stroke Study between January 2003 and June 2019 were included. Data including stroke treatment and recurrence were compared between subjects with and without cancer using Wilcoxon rank sum and chi-square tests. RESULTS: Cancer or tumor was present in 99 of 2968 children (3.3%) with arterial ischemic stroke and 64 of 596 children (10.7%) with cerebral sinovenous thrombosis. Among children in whom cancer type was identified, 42 of 88 arterial ischemic stroke cases (48%) had brain tumors and 35 (40%) had hematologic malignancies; 45 of 58 cerebral sinovenous thrombosis cases (78%) had hematologic malignancies and eight (14%) had brain tumors. Of 54 cancer-associated arterial ischemic stroke cases with a known cause, 34 (63%) were due to arteriopathy and nine (17%) were due to cardioembolism. Of 46 cancer-associated cerebral sinovenous thrombosis cases with a known cause, 41 (89%) were related to chemotherapy-induced or other prothrombotic states. Children with cancer were less likely than children without cancer to receive antithrombotic therapy for arterial ischemic stroke (58% vs 80%, P = 0.007) and anticoagulation for cerebral sinovenous thrombosis (71% vs 87%, P = 0.046). Recurrent arterial ischemic stroke (5% vs 2%, P = 0.04) and cerebral sinovenous thrombosis (5% vs 1%, P = 0.006) were more common among children with cancer. CONCLUSIONS: Cancer is an important risk factor for incident and recurrent childhood stroke. Stroke prevention strategies for children with cancer are needed.

Poor Outcomes Related to Anterior Extension of Large Hemispheric Infarction: Topographic Analysis of GAMES-RP Trial MRI Scans.

BACKGROUND: We aimed to assess the correlation of lesion location and clinical outcome in patients with large hemispheric infarction (LHI). METHODS: We analyzed admission MRI data from the GAMES-RP trial, which enrolled patients with anterior circulation infarct volumes of 82-300 cm3 within 10 hours of onset. Infarct lesions were segmented and co-registered onto MNI-152 brain space. Voxel-wise general linear models were applied to assess location-outcome correlations after correction for infarct volume as a co-variate. RESULTS: We included 83 patients with known 3-month modified Rankin scale (mRS). In voxel-wise analysis, there was significant correlation between admission infarct lesions involving the anterior cerebral artery (ACA) territory and its middle cerebral artery (MCA) border zone with both higher 3-month mRS and post-stroke day 3 and 7 National Institutes of Health Stroke Scale (NIHSS) total score and arm/leg subscores. Higher NIHSS total scores from admission through poststroke day 2 correlated with left MCA infarcts. In multivariate analysis, ACA territory infarct volume (P = .001) and admission NIHSS (P = .005) were independent predictors of 3-month mRS. Moreover, in a subgroup of 36 patients with infarct lesions involving right MCA-ACA border zone, intravenous (IV) glibenclamide (BIIB093; glyburide) treatment was the only independent predictor of 3-month mRS in multivariate regression analysis (P = .016). CONCLUSIONS: Anterior extension of LHI with involvement of ACA territory and ACA-MCA border zone is an independent predictor of poor functional outcome, likely due to impairment of arm/leg motor function. If confirmed in larger cohorts, infarct topology may potentially help triage LHI patients who may benefit from IV glibenclamide. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01794182.

Intravenous Glibenclamide Reduces Lesional Water Uptake in Large Hemispheric Infarction.

Background and Purpose- Prior studies have shown a linear relationship between computed tomography (CT)-derived radiodensity and water uptake, or brain edema, within stroke lesions. To test the hypothesis that intravenous glibenclamide (glyburide; BIIB093) reduces ischemic brain water uptake, we quantified the lesional net water uptake (NWU) on serial CT scans from patients enrolled in the phase 2 GAMES-RP Trial (Glyburide Advantage in Malignant Edema and Stroke). Methods- This was a post hoc exploratory analysis of the GAMES-RP study. Noncontrast CT scans performed between admission and day 7 (n=264) were analyzed in the GAMES-RP modified intention-to-treat sample. Quantitative change in CT radiodensity (ie, NWU) and midline shift (MLS) was measured. The gray and white matter NWU were also examined separately. Repeated-measures mixed-effects models were used to assess the effect of intravenous glibenclamide on MLS or NWU. Results- A median of 3 CT scans (interquartile range, 2-4) were performed per patient during the first 7 days after stroke. In a repeated-measures regression model, greater NWU was associated with increased MLS (ß=0.23; 95% CI, 0.20-0.26; P<0.001). Treatment with intravenous glibenclamide was associated with reduced NWU (ß=-2.80; 95% CI, -5.07 to -0.53; P=0.016) and reduced MLS (ß=-1.50; 95% CI, -2.71 to -0.28; P=0.016). Treatment with intravenous glibenclamide reduced both gray and white matter water uptake. In mediation analysis, gray matter NWU (ß=0.15; 95% CI, 0.11-0.20; P<0.001) contributed to a greater proportion of MLS mass effect, as compared with white matter NWU (ß=0.08; 95% CI, 0.03-0.13; P=0.001). Conclusions- In this phase 2 post hoc analysis, intravenous glibenclamide reduced both water accumulation and mass effect after large hemispheric infarction. This study demonstrates NWU is a quantitative and modifiable biomarker of ischemic brain edema accumulation. Clinical Trial Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT01794182.

Arterial Ischemic Stroke Secondary to Cardiac Disease in Neonates and Children.

OBJECTIVE: We describe the risk factors for peri-procedural and spontaneous arterial ischemic stroke (AIS) in children with cardiac disease. METHODS: We identified children with cardiac causes of AIS enrolled in the International Pediatric Stroke Study registry from January 2003 to July 2014. Isolated patent foramen ovale was excluded. Peri-procedural AIS (those occurring during or within 72 hours of cardiac surgery, cardiac catheterization, or mechanical circulatory support) and spontaneous AIS that occurred outside of these time periods were compared. RESULTS: We identified 672 patients with congenital or acquired cardiac disease as the primary risk factor for AIS. Among these, 177 patients (26%) had peri-procedural AIS and 495 patients (74%) had spontaneous AIS. Among non-neonates, spontaneous AIS occurred at older ages (median 4.2 years, interquartile range 0.97 to 12.4) compared with peri-procedural AIS (median 2.4 years, interquartile range 0.35 to 6.1, P < 0.001). About a third of patients in both groups had a systemic illness at the time of AIS. Patients who had spontaneous AIS were more likely to have a preceding thrombotic event (16 % versus 9 %, P = 0.02) and to have a moderate or severe neurological deficit at discharge (67% versus 33%, P = 0.01) compared to those with peri-procedural AIS. CONCLUSIONS: Children with cardiac disease are at risk for AIS at the time of cardiac procedures but also outside of the immediate 72 hours after procedures. Many have acute systemic illness or thrombotic event preceding AIS, suggesting that inflammatory or prothrombotic conditions could act as a stroke trigger in this susceptible population.

Neurologic Outcome Predictors in Pediatric Intracerebral Hemorrhage: A Prospective Study.

BACKGROUND AND PURPOSE: Intracerebral hemorrhage is a considerable source of morbidity and mortality. This 3-center study describes outcomes of pediatric intracerebral hemorrhage and identifies 2-year neurological outcome predictors. METHODS: Children 29 days to 18 years of age presenting with intracerebral hemorrhage from March 2007 to May 2015 were enrolled prospectively. Exclusion criteria included trauma; intracranial tumor; hemorrhagic transformation of arterial ischemic stroke or cerebral sinovenous thrombosis; isolated subdural, epidural, or subarachnoid hemorrhage; and abnormal baseline neurological function. Intracerebral hemorrhage and total brain volumes were measured on neuroimaging. The Pediatric Stroke Outcome Measure assessed outcomes. RESULTS: Sixty-nine children were included (median age: 9.7 years; interquartile range: 2.2-14). Six children (9%) died during hospitalization. Outcomes in survivors were assessed at early follow-up in 98% (median 3.1 months; interquartile range: 3.1-3.8) and at later follow-up in 94% (median: 2.1 years; interquartile range: 1.3-2.8). Over a third had a significant disability at 2 years (Pediatric Stroke Outcome Measure >2). Total Pediatric Stroke Outcome Measure score improved over time (P=0.0003), paralleling improvements in the sensorimotor subscore (P=0.0004). Altered mental status (odds ratio, 13; 95% confidence interval, 3.9-46; P<0.001), hemorrhage volume ≥4% of total brain volume (odds ratio, 17; 95% confidence interval, 1.9-156; P=0.01), and intensive care unit length of stay (odds ratio, 1.1; 95% confidence interval, 1.0-1.2; P=0.002) were significantly associated with poor 2-year outcome. CONCLUSIONS: Over one third of children experienced significant disability at 2 years. Improvements in outcomes were driven by recovery of sensorimotor function. Altered mental status, hemorrhage volume ≥4% of total brain volume, and intensive care unit length of stay were independent predictors of significant disability at 2 years.

Long-Term Outcomes in Patients Aged ≤70 Years With Intravenous Glyburide From the Phase II GAMES-RP Study of Large Hemispheric Infarction: An Exploratory Analysis.

BACKGROUND AND PURPOSE: We aimed to determine whether subjects aged ≤70 years who were treated with intravenous glyburide (RP-1127; BIIB093; glibenclamide) would have better long-term outcomes than those who received placebo. METHODS: GAMES-RP (Glyburide Advantage in Malignant Edema and Stroke-Remedy Pharmaceuticals) was a prospective, double-blind, randomized, placebo-controlled phase 2 clinical trial. Eighty-six participants, aged 18 to 80 years, who presented to 18 centers with large hemispheric infarction (baseline diffusion-weighted imaging volumes, 82-300 cm3) randomized within 10 hours of symptom onset were enrolled. In the current exploratory analysis, we included participants aged ≤70 years treated with intravenous glyburide (n=35) or placebo (n=30) who met per-protocol criteria. Intravenous glyburide or placebo was administered in a 1:1 ratio. We analyzed 90-day and 12-month mortality, functional outcome (modified Rankin Scale, Barthel Index), and quality of life (EuroQol group 5-dimension). Additional outcomes assessed included blood-brain barrier injury (MMP-9 [matrix metalloproteinase 9]) and cerebral edema (brain midline shift). RESULTS: Participants ≤70 years of age treated with intravenous glyburide had lower mortality at all time points (log-rank for survival hazards ratio, 0.34; P=0.04). After adjustment for age, the difference in functional outcome (modified Rankin Scale) demonstrated a trend toward benefit for intravenous glyburide-treated subjects at 90 days (odds ratio, 2.31; P=0.07). Repeated measures analysis at 90 days, 6 months, and 12 months using generalized estimating equations showed a significant treatment effect of intravenous glyburide on the Barthel Index (P=0.03) and EuroQol group 5-dimension (P=0.05). Participants treated with intravenous glyburide had lower plasma levels of MMP-9 (189 versus 376 ng/mL; P<0.001) and decreased midline shift (4.7 versus 9 mm; P<0.001) compared with participants who received placebo. CONCLUSIONS: In this exploratory analysis, participants ≤70 years of age with large hemispheric infarction have improved survival after acute therapy with intravenous glyburide. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01794182.

Malignant Cerebellar Edema Subsequent to Accidental Prescription Opioid Intoxication in Children.

We present two recent cases of toddlers who developed malignant cerebellar edema subsequent to accidental ingestion of prescription opioids. Both children presented acute neurological decline, hydrocephalus, and tonsillar herniation requiring emergent ventricular drain placement, suboccipital craniectomy, and partial cerebellectomy. Together with several other reports, these cases suggest the existence of an uncommon yet severe syndrome of acute opioid-induced malignant cerebellar edema. We hypothesize that the condition results from a combination of primary opioid receptor-mediated changes in neuronal metabolism that are exacerbated by secondary hypoxic insult. If recognized promptly, this syndrome can be treated with emergent neurosurgical intervention with good clinical outcomes. These cases also illustrate the unintended consequences and innocent victims of the spiraling prescription opioid epidemic, which will likely increase in prevalence. Recognition of this syndrome by clinicians is thus critical.

Incidence of Recurrence in Posterior Circulation Childhood Arterial Ischemic Stroke.

Importance: Childhood arterial ischemic stroke (CAIS) affects approximately 1.6 per 100 000 children per year, while stroke recurs in up to 20% of patients at 5 years. Factors determining the risk of recurrence are incompletely understood. Objective: To investigate the incidence of the recurrence of CAIS in the posterior and anterior circulations to determine if the risk differs between the 2 locations. Design, Setting, and Participants: A retrospective analysis of CAIS was conducted among children enrolled in a single-center prospective consecutive cohort at The Children's Hospital of Philadelphia between January 1, 2006, and January 1, 2015. Children with confirmed CAIS occurring between 29 days and 17.99 years were evaluated for inclusion. Patients were excluded if infarcts were located in both the anterior and posterior distributions or if CAIS occurred as a complication of intracranial surgery or brain tumor. Main Outcomes and Measures: Stroke recurrence. Results: The study population included 107 patients (75 boys [70.1%] and 32 girls [29.9%]; median age at AIS, 7.7 years [interquartile range, 3.1-13.6 years]). Sixty-one children had anterior circulation CAIS (ACAIS) and 46 had posterior circulation CAIS (PCAIS). Median follow-up was 20.9 months (interquartile range, 8.7-40.4 months). For ACAIS, recurrence-free survival was 100% at 1 month and 96% (95% CI, 85%-99%) at 1 and 3 years. For PCAIS, recurrence-free survival was 88% (95% CI, 75%-95%) at 1 month and 81% (95% CI, 66%-90%) at 1 and 3 years. The hazard ratio for recurrence after PCAIS compared with ACAIS was 6.4 (95% CI, 1.4-29.8; P = .02) in univariable analysis and 5.3 (95% CI, 1.1-26.4; P = .04) after adjusting for sex and cervical dissection. Conclusions and Relevance: We identified a subgroup of patients that comprise more than 80% of recurrences of CAIS. Three years after incident stroke, 19% of children with PCAIS had a recurrence compared with 4% of patients with ACAIS. Different mechanisms of stroke may account for this difference. Children with PCAIS may warrant increased monitoring. This study highlights the necessity for further research focused on recurrence prevention.