Down syndrome and moyamoya: clinical presentation and surgical management

Ischemic Stroke in a Seven-Year-Old Female With Down Syndrome and Newly Discovered Moyamoya Syndrome

Moyamoya represents a rare, progressive cerebrovascular disease, characterized by a gradual stenosis of the intracranial internal carotid arteries, thereby increasing the risk of stroke. Down syndrome is known to be a predisposing factor for Moyamoya syndrome. This review discusses a distinctive case of a seven-year-old female with Down syndrome who manifested with Moyamoya syndrome, evident from acute stroke-like symptoms.

Surgical revascularizations for pediatric moyamoya: a systematic review, meta-analysis, and meta-regression analysis

INTRODUCTION

There is no clear consensus regarding the technique of surgical revascularization for moyamoya disease and syndrome (MMD/MMS) in the pediatric population. Previous meta-analyses have attempted to address this gap in literature but with methodological limitations that affect the reliability of their pooled estimates. This meta-analysis aimed to report an accurate and transparent comparison between studies of indirect (IB), direct (DB), and combined bypasses (CB) in pediatric patients with MMD/MMS.

METHODS

In accordance with PRISMA guidelines, systematic searches of Medline, Embase, and Cochrane Central were undertaken from database inception to 7 October 2022. Perioperative adverse events were the primary outcome measure. Secondary outcomes were rates of long-term revascularization, stroke recurrence, morbidity, and mortality.

RESULTS

Thirty-seven studies reporting 2460 patients and 4432 hemispheres were included in the meta-analysis. The overall pooled mean age was 8.6 years (95% CI: 7.7; 9.5), and 45.0% were male. Pooled proportions of perioperative adverse events were similar between the DB/CB and IB groups except for wound complication which was higher in the former group (RR = 2.54 (95% CI: 1.82; 3.55)). Proportions of post-surgical Matsushima Grade A/B revascularization favored DB/CB over IB (RR = 1.12 (95% CI 1.02; 1.24)). There was no significant difference in stroke recurrence, morbidity, and mortality. After meta-regression analysis, year of publication and age were significant predictors of outcomes.

CONCLUSIONS

IB, DB/CB are relatively effective and safe revascularization options for pediatric MMD/MMS. Low-quality GRADE evidence suggests that DB/CB was associated with better long-term angiographic revascularization outcomes when compared with IB, although this did not translate to long-term stroke and mortality benefits.

Pediatric Moyamoya Biomarkers: Narrowing the Knowledge Gap

Moyamoya is a progressive cerebrovascular disorder that leads to stenosis of the arteries in the distal internal carotid, proximal middle cerebral and proximal anterior cerebral arteries of the circle of Willis. Typically a network of collaterals form to bypass the stenosis and maintain cerebral blood flow. As moyamoya progresses it affects the anterior circulation more commonly than posterior circulation, and cerebral blood flow becomes increasingly reliant on external carotid supply. Children with moyamoya are at increased risk for ischemic symptoms including stroke and transient ischemic attacks (TIA). In addition, cognitive decline may occur over time, even in the absence of clinical stroke. Standard of care for stroke prevention in children with symptomatic moyamoya is revascularization surgery. Treatment of children with asymptomatic moyamoya with revascularization surgery however remains more controversial. Therefore, biomarkers are needed to assist with not only diagnosis but also with determining ischemic risk and identifying best surgical candidates. In this review we will discuss the current knowledge as well as gaps in research in relation to pediatric moyamoya biomarkers including neurologic presentation, cognitive, neuroimaging, genetic and biologic biomarkers of disease severity and ischemic risk.

Moyamoya Disease From an Otolaryngologist’s Perspective: A Rare Case

Moyamoya disease is characterized by narrowing of cerebral blood vessels and is progressive in nature. We present the case of a 21-year-old female patient who was a known case of Down’s syndrome and presented with right-sided facial muscle weakness and was initially suspected of having cholesteatoma, but no evidence for the same was found after extensive radiological investigations. The suspicion of a central nervous system pathology was raised due to the clinical findings of dysphasia and supranuclear facial palsy. Magnetic-resonance angiography (MRA) was suggestive of findings of early Moyamoya disease. After a Neurologist consultation, the patient was started on conservative management with anti-platelet drugs and Statins and had symptomatic improvement. The patient was advised regular follow-up and had no fresh episodes of similar complaints.

Moyamoya syndrome presenting in an adult with Down syndrome: A case report with a literature review

Moyamoya disease is an unusual occlusive cerebrovascular condition commonly seen in children, marked by stenosis of the internal carotid artery and circle of Willis, causing, cerebral ischemia. Moyamoya syndrome is a Moyamoya-like arteriopathy with risk factors including autoimmune disorders, thyroid disease, sickle cell disease, or Down syndrome. Trisomy 21 is a genetic disorder consistent with specific physical and behavioral characteristics, with intellectual impairment. We describe a rare case of Moyamoya syndrome manifesting as ischemic stroke in an adult with Down syndrome

Cardiovascular Physiology and Pathophysiology in Down Syndrome

Down Syndrome (Ds) is the most common chromosomal cause of intellectual disability that results from triplication of chromosome 21 genes. Individuals with Ds demonstrate cognitive deficits in addition to comorbidities including cardiac defects, pulmonary arterial hypertension (PAH), low blood pressure (BP), and differences in autonomic regulation. Many individuals with Ds are born with heart malformations and some can be surgically corrected. Lower BP at rest and in response to exercise and other stressors are a prevalent feature in Ds. These reduced cardiovascular responses may be due to underlying autonomic dysfunction and have been implicated in lower exercise/work capacity in Ds, which is an important correlate of morbidity, mortality and quality of life. Exercise therapy can be beneficial to normalize autonomic function and may help prevent the development of co-morbidities in Ds. We will review cardiovascular physiology and pathophysiology in individuals with Ds, along with exercise therapy and special considerations for these individuals.

Western Moyamoya Phenotype: A Scoping Review

Moyamoya, a rare angiographic finding, is characterized by chronic and progressive stenosis at the terminal end of the internal carotid artery, followed by collateralization of the cerebral vasculature at the base of the skull. Coined by Suzuki and Takaku in 1969, the term "moyamoya" means a "puff of smoke" in Japanese, a reference to the angiographic appearance of moyamoya collateralization. Moyamoya is most commonly found in East Asian countries, where much governmental and civilian effort has been expended to characterize this unique disease process. However, despite its rarity, the occurrence of moyamoya in Western countries is associated with significant divergence regarding incidence, gender, sex, age at diagnosis, clinical presentation, and outcomes. Here, we attempted to review the Western literature on moyamoya presentation using the PubMed database to characterize the Western phenotype of moyamoya. We were guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews (PRISMA-ScR). We reviewed papers generated from a search with keywords "moyamoya case report," those reported from a Western institution, and those reported on a relevant association. Our scoping review demonstrated various clinical associations with moyamoya. Moreover, we summarized the demographic profile and clinical symptomatology, as well as reported disease associations to better elucidate the Western phenotype of moyamoya.

Increased Autoimmunity in Individuals With Down Syndrome and Moyamoya Disease

Objective: To determine if elevated rates of autoimmune disease are present in children with both Down syndrome and moyamoya disease given the high rates of autoimmune disease reported in both conditions and unknown etiology of angiopathy in this population. Methods: A multi-center retrospective case-control study of children with Down syndrome and moyamoya syndrome, idiopathic moyamoya disease, and Down syndrome without cerebrovascular disease was performed. Outcome measures included presence of autoimmune disease, presence of autoantibodies and angiopathy severity data. Comparisons across groups was performed using the Kruskal-Wallis, χ2 and multivariate Poisson regression. Results: The prevalence of autoimmune disease were 57.7, 20.3, and 35.3% in persons with Down syndrome and moyamoya syndrome, idiopathic moyamoya disease, and Down syndrome only groups, respectively (p < 0.001). The prevalence of autoimmune disease among children with Down syndrome and moyamoya syndrome is 3.2 times (p < 0.001, 95% CI: 1.82-5.58) higher than the idiopathic moyamoya group and 1.5 times (p = 0.002, 95% CI: 1.17-1.99) higher than the Down syndrome only group when adjusting for age and sex. The most common autoimmune diseases were thyroid disorders, type I diabetes and Celiac disease. No individuals with idiopathic moyamoya disease had more than one type of autoimmune disorder while 15.4% of individuals with Down syndrome and moyamoya syndrome and 4.8% of individuals with Down syndrome only had >1 disorder (p = 0.05, 95%CI: 1.08-6.08). Interpretation: This study reports elevated rates of autoimmune disease in persons with Down syndrome and moyamoya syndrome providing a nidus for study of the role of autoimmunity in angiopathy in this population.

Implementation and Rationale for a Unified Clinical and Imaging Protocol for Evaluation and Treatment of Moyamoya Angiopathy: A Single Institutional Experience

Moyamoya disease (MMD) is a complex and incompletely-understood cerebrovascular pathological entity that requires thorough clinical and imaging evaluation. Moyamoya is rare, thereby making the establishment of an effective, thorough and interdisciplinary patient evaluation protocol challenging, even within specialized referral centers. Nevertheless, implementation of such a protocol is crucial in order to provide the best possible evaluation and treatment for MMD patients. Here, we describe our institution's implementation of, rationale for, and experience with a comprehensive multidisciplinary collaboration and evaluation strategy for adult patients with moyamoya. This evaluation course consists of, first of all, a thorough clinical and laboratory evaluation with a vascular neurologist. This is followed by a comprehensive imaging assessment which evaluates angiographic and parenchymal features, in addition to cerebrovascular functionality. Finally, appropriate referrals are made to consulting services as indicated, which includes vascular neurosurgery. These steps are described in detail herein.

Non-invasive Urinary Biomarkers in Moyamoya Disease

Introduction: A major difficulty in treating moyamoya disease is the lack of effective methods to detect novel or progressive disease prior to the onset of disabling stroke. More importantly, a tool to better stratify operative candidates and quantify response to therapy could substantively complement existing methods. Here, we present proof-of-principle data supporting the use of urinary biomarkers as diagnostic adjuncts in pediatric moyamoya patients.

Methods: Urine and cerebrospinal fluid specimens were collected from pediatric patients with moyamoya disease and a cohort of age and sex-matched control patients. Clinical and radiographic data were paired with measurements of a previously validated panel of angiogenic proteins quantified by ELISA. Results were compared to age and sex-matched controls and subjected to statistical analyses.

Results: Evaluation of a specific panel of urinary and cerebrospinal fluid biomarkers by ELISA demonstrated significant elevations of angiogenic proteins in samples from moyamoya patients compared to matched controls. ROC curves for individual urinary biomarkers, including MMP-2, MMP-9, MMP-9/NGAL, and VEGF, showed excellent discrimination. The optimal urinary biomarker was MMP-2, providing a sensitivity of 88%, specificity of 100%, and overall accuracy of 91%. Biomarker levels changed in response to therapy and correlated with radiographic evidence of revascularization.

Conclusions: We report, for the first time, identification of a panel of urinary biomarkers that predicts the presence of moyamoya disease. These biomarkers correlate with presence of disease and can be tracked from the central nervous system to urine. These data support the hypothesis that urinary proteins are useful predictors of the presence of moyamoya disease and may provide a basis for a novel, non-invasive method to identify new disease and monitor known patients following treatment.

Moyamoya Syndrome Presenting as Refractory Status Epilepticus in a 32-Year-Old Female

Moyamoya disease (MMD) is a rare cerebrovascular occlusion condition characterized by ‎progressive stenosis in the terminal portion of the internal carotid arteries on both sides. The measured incidence of MMD is 0.086 per 100,000 people. MMD has variable ‎neurological manifestations, however, seizure is a significant manifestation of MMD with ‎few reported studies. The combination of sickle cell disease (SCD) and MMD confers a much ‎higher risk of ischemic stroke. In this paper, we describe a 32-year-old female with a known ‎case of SCD taking tramadol for a vaso-occlusive crisis, who was presented to the emergency ‎department by a family member due to a low level of consciousness. Despite ongoing ‎management, the patient developed multiple seizure attacks and intubation was ‎performed. A computed tomography (CT) brain angiogram was performed, and the ‎diagnosis of MMD was made. The patient was shifted to the intensive care unit (ICU) and in spite of the ongoing management in the ICU, the patient died. In this case, we highlight the importance of considering MMD as a ‎differential diagnosis when dealing with an SCD patient who developed refractory status epilepticus.‎

Neurologic complications of Down syndrome: a systematic review

Down syndrome (DS) is one of the most well-recognized genetic disorders. Persons with DS are known to have a variety of co-morbid medical problems, affecting nearly all organ systems. Improved healthcare interventions and research have allowed for increased life span of persons with DS, although disorders of the neurologic system remain underexplored. The purpose of this systematic review is to provide clinically pertinent information on the neurological phenotypes of frequently occurring or clinically relevant conditions. A retrospective review of MEDLINE, Scopus, and Pubmed were used to identify sources among seventeen, clinically relevant, search categories. MeSH terms all contained the phrase "Down Syndrome" in conjunction with the topic of interest. 'Frequently-occurring' was defined as prevalent in more than 10% of persons with DS across their lifespan, whereas 'clinically-relevant' was defined as a disease condition where early diagnosis or intervention can augment the disease course. In total, 4896 sources were identified with 159 sources meeting criteria for inclusion. Seventeen clinical conditions were grouped under the following subjects: hypotonia, intellectual and learning disability, cervical instability, autism spectrum disorder, epilepsy, cerebrovascular disease, Alzheimer's disease and neuropsychiatric disease. The results of this review provide a blueprint for the clinical neurologist taking care of persons with DS across the age spectrum and indicate that there are many underrecognized and misdiagnosed co-occurring conditions in DS, highlighting the need for further research.

Multiorgan involvement and management in children with Down syndrome

AIM

To review multiorgan involvement and management in children with Down syndrome (DS).

METHODS

A literature review of articles from 1980 to 2019 using the MEDLINE interface of PubMed was performed using the following search terms- [Down syndrome] or [Trisomy 21] AND [Cardiology] or [Respiratory] or [neurodevelopment] or [epilepsy] or [musculoskeletal] or [immune system] or [haematological] or [endocrine] or [gastrointestinal] or [ophthalmological] or [Ear Nose Throat] or [dermatology] or [renal].

RESULTS

Congenital heart disease particularly septal defects occur in over 60% of infants with DS and 5%-34% of infants develop persistent pulmonary hypertension of the newborn irrespective of a diagnosis of congenital heart disease. Early recognition and management of aspiration, obstructive sleep apnoea and recurrent lower respiratory tract infections (LRTI) could reduce risk of developing pulmonary hypertension in later childhood. Children with DS have an increased risk of autistic spectrum disorder, attention deficit disorder and epilepsy particularly infantile spasms, which are associated with poor neurodevelopmental outcomes. Congenital anomalies of the gastrointestinal and renal system as well as autoimmune diseases, coeliac disease, arthropathy, thyroid dysfunction fold diabetes mellitus and dermatological conditions are more common. Hearing and visual anomalies are also well recognised association with DS (Table 1).

CONCLUSION

Children with DS are at an increased risk of multiorgan comorbidities. Organ-specific health surveillance may provide holistic care for the children and families with DS throughout childhood.

Postintravenous immunoglobulin stroke in a toddler with Down syndrome: a diagnostic challenge

Children with Down syndrome have a higher risk of stroke. Similarly, intravenous immunoglobulin (IV Ig) is also known to cause a stroke. We reported a 3-year-old boy with Down syndrome who presented with severe pneumonia and received IV Ig. He developed right hemiparesis 60 hours after the infusion. Blood investigations, echocardiography and carotid Doppler did not suggest vasculitis, thrombophilia or extracranial dissection. Brain computerised tomography (CT) showed acute left frontal and parietal infarcts. Initial magnetic resonance angiography (MRA) of cerebral vessels showed short segment attenuations of both proximal middle cerebral arteries and reduction in the calibre of bilateral supraclinoid internal carotid arteries. The boy was treated with enoxaparin and aspirin. He only had partial recovery of the hemiparesis on follow-up. A repeat MRA 13 months later showed parenchymal collateral vessels suggestive of moyamoya disease. We recommend imaging the cerebral vessels in children with a high risk of moyamoya before giving IV Ig.

Moyamoya disease versus moyamoya syndrome: comparison of presentation and outcome in 338 hemispheres

OBJECTIVE

Phenotypic differences between moyamoya disease (MMD) and moyamoya syndrome (MMS) remain unclear. The purpose of this study was to evaluate whether such differences exist when presentation, procedure-related, and outcome variables are compared quantitatively.

METHODS

The study cohort included 185 patients with moyamoya presenting to the Johns Hopkins Medical Institutions between 1994 and 2015. Baseline demographic, angiographic, and clinical characteristics were compared between patients with MMS and MMD, in addition to procedure-related complications and length of stay (LOS) after surgery. Stroke-free survival was compared between both disease variants after diagnosis. Kaplan-Meier analysis and Cox proportional hazards regression were used to compare stroke-free survival between surgically treated and conservatively managed hemispheres in both types of disease, while evaluating interaction between disease variant and management.

RESULTS

The cohort consisted of 137 patients with MMD (74%) with a bimodal age distribution and 48 patients with MMS (26%) who were mostly under 18 years of age (75%). Underlying diseases included sickle cell disease (48%), trisomy 21 (12%), neurofibromatosis (23%), and other disorders (17%). Patients with MMS were younger (p < 0.001) and less likely to be female (p = 0.034). Otherwise, baseline characteristics were statistically comparable. The rate of surgical complications was 33% in patients with MMD and 16% in patients with MMS (p = 0.097). Both groups of patients had a similar LOS after surgery (p = 0.823). Survival analysis (n = 330 hemispheres) showed similar stroke-free survival after diagnosis (p = 0.856) and lower stroke hazard in surgically managed patients in both MMD (hazard ratio [HR] 0.29, p = 0.028) and MMS (HR 0.62, p = 0.586). The disease variant (MMD vs MMS) did not affect the relationship between management approach (surgery vs conservative) and stroke hazard (p = 0.787).

CONCLUSIONS

MMD and MMS have largely comparable clinical and angiographic phenotypes with analogously favorable responses to surgical revascularization.

Surgical outcomes for pediatric moyamoya: a systematic review and meta-analysis

OBJECTIVE

The optimal revascularization for pediatric moyamoya for reducing the incidence of future stroke events remains to be determined.

METHODS

The authors conducted a search of PubMed, MEDLINE, Embase, and Web of Science electronic databases from inception until January 2019. The primary endpoint was the presence of a future ischemic stroke event. Secondary endpoints were angiographic outcomes as measured by postoperative Matsushima grade and clinical symptom persistence. Patients who underwent either direct or combined direct/indirect revascularization were classified into the direct cohort. Data from each study on presence of postoperative stroke events were used to generate standardized mean differences and 95% confidence intervals, which were combined using inverse variance-weighted averages of standardized mean differences in a random effects model.

RESULTS

Twenty-nine studies met the inclusion criteria for analysis, comprising 2258 patients (1011 males, mean age 8.3 ± 1.8 years) who were followed up clinically for an average of 71.4 ± 51.3 months. One hundred fifty-four patients underwent direct bypass alone, 680 patients underwent either direct or combined direct/indirect revascularization procedures, while 1424 patients underwent indirect bypass alone. The frequencies of future stroke events in patients undergoing direct bypass alone, combined bypass, or indirect bypass alone were 1 per 190.3 patient-years, 1 per 108.9 patient-years, and 1 per 61.1 patient-years, respectively, in each cohort. The estimated stroke rates were 9.0% with indirect revascularization, 4.5% with direct revascularization alone, and 6.0% with combined revascularization. A forest plot did not reveal any significant differences in the incidence of future stroke events or angiographic outcomes following direct-only, combined, or indirect-only revascularization.

CONCLUSIONS

Direct, indirect, and combined indirect/direct bypass techniques are all effective revascularization options for pediatric moyamoya disease. A relative paucity of granular studies-and inherent surgical selection bias-limits direct comparison between interventions. Suitably designed prospective cohort studies may be useful in identifying patients likely to receive benefit from specific procedures.

Adult moyamoya angiopathy in Bourgogne-Franche-Comté: Epidemiology, diagnosis and management

INTRODUCTION

Moyamoya angiopathy (MMA) is a progressive steno-occlusive disease of the distal internal carotid arteries mainly described in Asia. It induces the development of collateral vascular networks to reduce chronic cerebral hypoperfusion. Symptoms depend on the patient's age in Asia: children are at greater risk of transient or constituted ischemic events, whereas adults are more exposed to hemorrhagic stroke. Data from the literature seem to show that the pattern of MMA in western countries differs from that in Asia.

MATERIAL AND METHODS

A retrospective study of patients with MMA was conducted in Bourgogne-Franche-Comté (mid-eastern France). Clinical data (symptoms, risk factors, age at diagnosis, number and timing of recurrences, type of treatment) as well as radiological data (angiographic findings, Suzuki's grade) were analyzed.

RESULTS

Seventeen adult patients (9 men, 53%) were followed at the university hospitals of Besançon and Dijon from 2009 to 2016. Fourteen patients (83%) had bilateral disease. The mean age at diagnosis was 49 years (±16), 83% of the patients were Caucasian and 17% originated from Maghreb. Only 17% of the hemispheres had a hemorrhagic form. Ischemic form was more frequent before diagnosis with transient ischemic attack (24% of patients) and stroke (83% of patients). With medical treatment, 9 patients suffered from stroke recurrence (53% of patients) with an average delay of 22.7±34 months. Three patients (18%) had combined surgical management by encephelo-synangiosis and superficial temporal artery-to-middle cerebral artery (STA-MCA) anastomosis, without symptom recurrence after treatment with an average follow up of 14 months.

CONCLUSION

MMA remains a rare cerebrovascular disease in Europe and requires multidisciplinary care. Epidemiological analysis showed differences with the Asian population, especially the predominance of ischemic forms in adults.

Down syndrome associated moyamoya may worsen epilepsy control and can benefit from surgical revascularization

Objectives

To examine outcome of bilateral extracranial to intracranial (EC-IC) bypass surgeries for a Down syndrome patient with hard-to-treat epilepsy and moyamoya.

Materials and methods

Superficial temporal arteries were anastamosed using an indirect bypass technique to middle cerebral arteries bilaterally to help limit perfusion deficits and seizure controls.

Results

Two superficial temporal to middle cerebral artery indirect bypass surgeries were performed within 3 months. Post-revascularization improvements included seizure control, gait, perfusion, wakefulness, language and quality of life.

Conclusion

In patients with Down syndrome and moyamoya, improvements in seizure control and quality of life may occur with EC-IC bypass procedures.

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Moyamoya blood flow compromises can be seen in Down syndrome.

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Both moyamoya and Down syndrome are associated with Epilepsy.

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If moyamoya related perfusion worsens, so can seizure control.

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We report bilateral indirect extracranial to intracranial bypass surgeries in a Down syndrome patient with moyamoya.

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The surgeries markedly improved seizure control and quality of life.

Down Syndrome with Moyamoya Disease: A Case Series

Down syndrome (DS), resulting from trisomy 21, is a common cause of mental retardation. Around 20,000 babies with DS are born every year in India. There is an increased risk of cerebral infarction in children with DS, the common causes being thromboembolism secondary to atrioventricular canal defects, right-to-left shunting, myocardial dysmotility, or cardiac valvular abnormalities. Stroke due to other causes can also occur in patients with DS, and one of these is moyamoya disease. This can be diagnosed by magnetic resonance imaging and/or angiography in these patients. Here we report four cases of moyamoya disease in young patients with DS aged 2–3½ years, of a total of 500 cases with DS registered in the Genetic Clinic.

Down syndrome and Moyamoya disease: unusual cause of stroke

Down syndrome is a frequent clinical entity, being considered one of the most frequent chromosomal aberrations. It is characterised by a typical clinical phenotype and is associated with a heterogeneous group of organ and system-specific abnormalities. The cardiovascular system is commonly affected and if so, it may be associated with an increased morbidity and mortality. Cerebrovascular events in patients with Down syndrome are multifactorial, being possibly related to congenital heart disease, vascular malformations and traditional cardiovascular risk factors. Moyamoya disease is a rare chronic occlusive vascular disease causing stenosis of the distal portion of the internal carotid artery, which has been associated with Down syndrome. The authors report the case of a 26-year-old woman with Down syndrome who presented with an acute stroke secondary to Moyamoya disease. The case is noteworthy for the rarity of this clinicopathological entity, and serves as a reminder for the possible association between these two conditions.

Incidence, clinical features, and treatment of familial moyamoya in pediatric patients: a single-institution series

OBJECTIVE Limited data exist on familial moyamoya in children. The purpose of this study was to characterize presentation and outcomes of pediatric moyamoya patients who have relatives diagnosed with moyamoya. METHODS The authors performed a single-institution retrospective analysis of a case series including all surgically treated children with moyamoya with first- or second-degree relatives with moyamoya. Clinical and radiographic characteristics were analyzed, along with surgical outcomes. RESULTS A total of 537 patients underwent surgery for moyamoya during the study period. Eighteen of those patients (3.4% of the total series) had moyamoya and a family history of moyamoya and were included in this study. Of these 18 patients, 14 were non-twin siblings, and the remaining 4 represented 2 pairs of identical (affected) twins. The presentation was predominantly ischemic (72%), but 4 patients (33%) were asymptomatic when they were found to have moyamoya. Bilateral disease was present in 13 patients (72%). Radiographic stroke prevalence (67%), Suzuki grade (3.3), and angiographic findings were comparable to findings in nonfamilial moyamoya patients. Thirty revascularization procedures were performed, with a 3.3% operative stroke rate per hemisphere and no new strokes in an average follow-up period of 4.5 years. CONCLUSIONS In a North American surgical series, familial moyamoya existed in 3.4% of cases, and was distinguished by manifesting in a broad range of ethnic groups, with a higher proportion of male patients and increased rates of asymptomatic and unilateral disease in comparison to nonfamilial moyamoya. Screening indications remain controversial and the current data are used to suggest guidelines. Surgical therapy is warranted, effective, and durable in these patients, but patients should be carefully selected.

Moyamoya Syndrome in South African Children With HIV-1 Infection

A national multicenter study identified 17 South African children with vertically acquired HIV-1 infection and HIV-associated vasculopathy. Five of the children (all indigenous African ancestry) had progressive vascular disease, consistent with moyamoya syndrome. Median presentation age 5.8 years (range 2.2-11). The children with moyamoya syndrome presented with abnormal CD4 counts and raised viral loads. Clinical features included motor deficits, neuroregression, and intellectual disability. Neuroimaging supported progressive vascular disease with preceding clinically silent disease course. Neurologic recovery occurred in 1 patient with improved CD4 counts. Four of the 5 children presented during the era when access to antiretroviral therapy was limited, suggesting that with improved management of HIV-1, progressive vasculopathy is less prevalent. However the insidious disease course illustrated indicates that the syndrome can progress "silently," and manifest with misleading phenotypes such as cognitive delay or regression. Sub-Saharan Africa has limited access to neuroimaging and affected children may be underdiagnosed.

National Analysis of 2454 Pediatric Moyamoya Admissions and the Effect of Hospital Volume on Outcomes

BACKGROUND AND PURPOSE

Comprehensive multicenter data on treatment of pediatric moyamoya in the United States is lacking. We sought to identify national trends in the diagnosis and treatment of this disease.

METHODS

A total of 2454 moyamoya admissions from 1997 to 2012 were identified from the Kids Inpatient Database. Demographics, inpatient costs, interventions, and discharge status were analyzed. Admissions with and without surgical revascularization were reviewed separately. The effect of hospital moyamoya volume on outcomes was analyzed by multivariate regression analysis.

RESULTS

Care of moyamoya patients has been concentrating at high-volume centers during the past 12 years. Among moyamoya admission without surgical revascularization, high-volume hospitals show no difference in length of stay, cost, or complications compared with low-volume centers. However, low-volume hospitals have more nonroutine discharges (odds ratio, 2.32; P=0.0005) and inpatient deaths (odds ratio, 12.7; P=0.02) when no revascularization was performed. In contrast, among admissions with surgical revascularization, high-volume centers had decreased length of stay (4.7 versus 6.2 days; P=0.004), reduced cost ($88 000 versus $138 000; P<0.0001), and no increase in complications (P=0.29) compared with low-volume centers. Admissions with revascularization to low-volume hospitals also had increased likelihood of nonroutine discharge (odds ratio, 8.23; P=0.02) compared with high-volume centers.

CONCLUSIONS

This is the largest study of US pediatric moyamoya admissions to date. These data demonstrate that volume correlates with outcome, indicating high-volume centers provide significantly improved care and reduced mortality in pediatric moyamoya patients, with the most marked benefit observed in admissions for surgical revascularization.