Intellectual decline in children with moyamoya and sickle cell anaemia

Clinical Outcome, Cognition, and Cerebrovascular Reactivity after Surgical Treatment for Moyamoya Vasculopathy: A Dutch Prospective, Single-Center Cohort Study

Background: It remains unclear whether revascularization of moyamoya vasculopathy (MMV) has a positive effect on cognitive function. In this prospective, single-center study, we investigated the effect of revascularization on cognitive function in patients with MMV. We report clinical and radiological outcome parameters and the associations between clinical determinants and change in neurocognitive functioning. Methods: We consecutively included all MMV patients at a Dutch tertiary referral hospital who underwent pre- and postoperative standardized neuropsychological evaluation, [15O]H2O-PET (including cerebrovascular reactivity (CVR)), MRI, cerebral angiography, and completed standardized questionnaires on clinical outcome and quality of life (QOL). To explore the association between patient characteristics, imaging findings, and change in the z-scores of the cognitive domains, we used multivariable linear- and Bayesian regression analysis. Results: We included 40 patients of whom 35 (27 females, 21 children) were treated surgically. One patient died after surgery, and two withdrew from the study. TIA- and headache frequency and modified Rankin scale (mRS) improved (resp. p = 0.001, 0.019, 0.039). Eleven patients (seven children) developed a new infarct during follow-up (31%), five of which were symptomatic. CVR-scores improved significantly (p < 0.0005). The language domain improved (p = 0.029); other domains remained stable. In adults, there was an improvement in QOL. We could not find an association between change in imaging and cognitive scores. Conclusion: In this cohort of Western MMV patients, TIA frequency, headache, CVR, and mRS improved significantly after revascularization. The language domain significantly improved, while others remained stable. We could not find an association between changes in CVR and cognitive scores.

Fronto-Parietal and White Matter Haemodynamics Predict Cognitive Outcome in Children with Moyamoya Independent of Stroke

Moyamoya disease is a major arteriopathy characterised by progressive steno-occlusion of the arteries of the circle of Willis. Studies in adults with moyamoya suggest an association between abnormal fronto-parietal and white matter regional haemodynamics and cognitive impairments, even in the absence of focal infarction. However, these associations have not been investigated in children with moyamoya. We examined the relationship between regional haemodynamics and ratings of intellectual ability and executive function, using hypercapnic challenge blood oxygen level-dependent magnetic resonance imaging of cerebrovascular reactivity in a consecutive cohort of children with confirmed moyamoya. Thirty children were included in the final analysis (mean age: 12.55 ± 3.03 years, 17 females, 15 idiopathic moyamoya and 15 syndromic moyamoya). Frontal haemodynamics were abnormal in all regardless of stroke history and comorbidity, but occipital lobe haemodynamics were also abnormal in children with syndromic moyamoya. Executive function deficits were noted in both idiopathic and syndromic moyamoya, whereas intellectual ability was impaired in syndromic moyamoya, even in the absence of stroke. Analysis of the relative effect of regional abnormal haemodynamics on cognitive outcomes demonstrated that executive dysfunction was predominantly explained by right parietal and white matter haemodynamics independent of stroke and comorbidity, while posterior circulation haemodynamics predicted intellectual ability. These results suggest that parietal and posterior haemodynamics play a compensatory role in overcoming frontal vulnerability and cognitive impairment.

Epidemiology of Stroke in Sickle Cell Disease

Sickle cell disease is the most common cause of stroke in childhood, both ischaemic and haemorrhagic, and it also affects adults with the condition. Without any screening or preventative treatment, the incidence appears to fall within the range 0.5 to 0.9 per 100 patient years of observation. Newborn screening with Penicillin prophylaxis and vaccination leading to reduced bacterial infection may have reduced the incidence, alongside increasing hydroxyurea prescription. Transcranial Doppler screening and prophylactic chronic transfusion for at least an initial year has reduced the incidence of stroke by up to 10-fold in children with time averaged mean of the maximum velocity >200 cm/s. Hydroxyurea also appears to reduce the incidence of first stroke to a similar extent in the same group but the optimal dose remains controversial. The prevention of haemorrhagic stroke at all ages and ischaemic stroke in adults has not yet received the same degree of attention. Although there are fewer studies, silent cerebral infarction on magnetic resonance imaging (MRI), and other neurological conditions, including headache, epilepsy and cognitive dysfunction, are also more prevalent in sickle cell disease compared with age matched controls. Clinical, neuropsychological and quantitative MRI screening may prove useful for understanding epidemiology and aetiology.

American Society of Hematology 2020 guidelines for sickle cell disease: prevention, diagnosis, and treatment of cerebrovascular disease in children and adults

BACKGROUND

Central nervous system (CNS) complications are among the most common, devastating sequelae of sickle cell disease (SCD) occurring throughout the lifespan.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology are intended to support the SCD community in decisions about prevention, diagnosis, and treatment of the most common neurological morbidities in SCD.

METHODS

The Mayo Evidence-Based Practice Research Program supported the guideline development process, including updating or performing systematic evidence reviews. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including GRADE evidence-to-decision frameworks, to assess evidence and make recommendations.

RESULTS

The panel placed a higher value on maintaining cognitive function than on being alive with significantly less than baseline cognitive function. The panel developed 19 recommendations with evidence-based strategies to prevent, diagnose, and treat CNS complications of SCD in low-middle- and high-income settings.

CONCLUSIONS

Three of 19 recommendations immediately impact clinical care. These recommendations include: use of transcranial Doppler ultrasound screening and hydroxyurea for primary stroke prevention in children with hemoglobin SS (HbSS) and hemoglobin Sβ0 (HbSβ0) thalassemia living in low-middle-income settings; surveillance for developmental delay, cognitive impairments, and neurodevelopmental disorders in children; and use of magnetic resonance imaging of the brain without sedation to detect silent cerebral infarcts at least once in early-school-age children and once in adults with HbSS or HbSβ0 thalassemia. Individuals with SCD, their family members, and clinicians should become aware of and implement these recommendations to reduce the burden of CNS complications in children and adults with SCD.

Anesthetic challenges in pediatric moyamoya disease: A report of two cases

Moyamoya disease (MMD), a rare cause of pediatric stroke, is a cerebrovascular occlusive disorder resulting from progressive stenosis of the distal intracranial carotid arteries and their proximal branches. In response to brain ischemia, there is the development of basal collateral vessels, which gives rise to the characteristic angiographic appearance of moyamoya (puff of smoke). If left untreated, the disease can result in overwhelming permanent neurological and cognitive deficits. Whereas MMD refers to the idiopathic form, moyamoya syndrome refers to the condition in which children with moyamoya also have a recognized clinical disorder. The classic pediatric presentation in moyamoya is recurrent transient ischemic attacks (TIAs) and/or completed/repeated ischemic strokes. Surgical revascularization, including direct and indirect techniques, remains the mainstay of treatment and has been shown to improve long-term outcome in children with MMD. Various risk factors identified for perioperative complications are as follows: history of TIAs, severity of disease, intraoperative hypotension, hypercapnia and hypovolemia, and substantial reduction in hematocrit intraoperatively. Thus, providing perianesthetic care to pediatric patients undergoing revascularization procedure for MMD is like walking a tightrope, and we present two such cases handled successfully.

Association of cognitive function with cerebral blood flow in children with moyamoya disease

OBJECTIVE

The cognitive effects of main cerebral artery occlusive lesions are unclear in children with moyamoya disease (MMD). The authors aimed to investigate cognitive function in the presurgical phase of pediatric patients with MMD with no apparent brain lesions.

METHODS

In this prospective, observational, single-center study, 21 children (mean age 10 ± 3.0 years, range 5-14 years) diagnosed with MMD at Hokkaido University Hospital between 2012 and 2018 were enrolled. A cross-sectional evaluation of intellectual ability was performed using the Wechsler Intelligence Scale for Children-Fourth Edition at the initial diagnosis. rCBF was measured using [123I] N-isopropyl p-iodoamphetamine/SPECT. The associations among clinical factors, disease severity, regional cerebral blood flow (rCBF), and intelligence test scores were also examined.

RESULTS

The mean full-scale intelligence quotient (FIQ) was 101.8 ± 12.5 (range 76-125) in children with no apparent brain lesions. A significant difference in the intelligence scale index score was observed, most frequently (42.9%) between working memory index (WMI) and verbal comprehension index (VCI; VCI - WMI > 11 points). Regional CBF was significantly reduced both in the left and right medial frontal cortices (left: 61.3 ± 5.3 ml/100 g/min, right 65.3 ± 5.3 ml/100 g/min; p < 0.001) compared to the cerebellum (77.8 ± 6.8 ml/100 g/min). There was a significant association of rCBF in the left dorsolateral prefrontal cortex (DLPFC) with FIQ (r = 0.46, p = 0.034), perceptual reasoning index (PRI; r = 0.44, p = 0.045), and processing speed index (PSI; r = 0.44, p = 0.045). There was an association between rCBF of the left medial frontal cortex and PSI (r = 0.49, p = 0.026). Age of onset, family history, ischemic symptoms, and angiographic severity were not associated with poor cognitive performance.

CONCLUSIONS

Although average intellectual ability was not reduced in children with MMD, the association of reduced rCBF in the left DLPFC and medial frontal cortex with FIQ, PRI, and PSI suggests mild cognitive dysfunction due to cerebral hypoperfusion.

Surgery for Moyamoya Disease in Children

Moyamoya disease is a chronic progressive cerebrovascular occlusive disease of the terminal portion of the internal carotid arteries associated with an acquired abnormal vascular network at the base of the brain, often leading to ischemic or hemorrhagic stroke. Moyamoya disease is a relatively common cause of pediatric stroke with a specific racial and well-identified clinical and imaging phenotype. Moyamoya disease is more prevalent in East Asian countries compared with other geographic regions with a higher incidence of familial cases and clinically more aggressive form. Moyamoya disease is one of the few causes of stroke that is amenable to effective surgical revascularization treatment. There are various surgical options available for revascularization, including the direct, indirect, or combined bypass techniques, each with variable responses. However, due to the heterogeneity of the diseases, different clinical course, geographical variables associated with the disease, and availability of a wide variety of surgical revascularization procedures, optimal selection of a surgical candidate and the surgical technique becomes challenging, particularly in the pediatric population. This brief review presents pertinent literature of clinical options for the diagnosis and surgical treatment of moyamoya disease in children.

Modified encephalo-duro-periosteal-synangiosis (EDPS) for the revascularization of anterior cerebral artery territory in moyamoya disease: A single-center experience

OBJECTIVES

Anterior cerebral artery (ACA) territory, a crucial area of intellectual development in children, is frequently involved in the progress of moyamoya disease (MMD). However, revascularization surgeries for this area are not as established as surgeries for middle cerebral artery (MCA) territory. This study aimed to describe our experience and study the effect of revascularizing ACA territory with periocranium and dural leaflets, which is referred to as 'encephalo-duro-periosteal-synangiosis (EDPS)'.

PATIENTS AND METHOD

Fourteen hemispheres of 9 MMD patients who had undergone EDPS from November 2015 till July 2017 in our hospital were retrospectively included. Clinical characteristics and procedure-related information were recorded. Cerebral perfusion was evaluated by computed tomography perfusion (CTP). Absolute and relative (r) CTP parameters of ROIs in ACA territory at the level of centrum semiovale and middle basal ganglia were calculated. Preoperative and postoperative parameters were compared.

RESULTS

All EDPS procedures were technically successful with no postoperative complications. The mean operating time was 75.00 ± 22.53 min per hemisphere. Postoperative absolute cerebral blood flow (CBF), rCBF were significantly increased and absolute time to peak (TTP), rTTP, absolute mean transit time (MTT) were significantly reduced in ACA territory at centrum semiovale level (P = 0.002, 0.045, 0.007, 0.005 and 0.039 respectively). Improved outcomes were achieved in five patients, stabilization in three and one patient had deterioration out of intracerebral hemorrhage during follow-up.

CONCLUSION

EDPS is a simple but effective technique to revascularize ACA territory for MMD. EDPS significantly improved cerebral blood perfusion of frontal lobe in the majority of patients without increasing procedure-related risks.

Effect of revascularization on cognitive outcomes in intracranial steno-occlusive disease: a systematic review

OBJECTIVESteno-occlusive diseases of the cerebral vasculature have been associated with cognitive decline. The authors performed a systematic review of the existing literature on intracranial steno-occlusive disease, including intracranial atherosclerosis and moyamoya disease (MMD), to determine the extent and quality of evidence for the effect of revascularization on cognitive performance.METHODSA systematic search of PubMed/MEDLINE, the Thomson Reuters Web of Science Core Collection, and the KCI Korean Journal Database was performed to identify randomized controlled trials (RCTs) in the English-language literature and observational studies that compared cognitive outcomes before and after revascularization in patients with steno-occlusive disease of the intracranial vasculature, from which data were extracted and analyzed.RESULTSNine papers were included, consisting of 2 RCTs and 7 observational cohort studies. Results from 2 randomized trials including 142 patients with symptomatic intracranial atherosclerotic steno-occlusion found no additional benefit to revascularization when added to maximal medical therapy. The certainty in the results of these trials was limited by concerns for bias and indirectness. Results from 7 observational trials including 282 patients found some cognitive benefit for revascularization for symptomatic atherosclerotic steno-occlusion and for steno-occlusion related to MMD in children. The certainty of these conclusions was low to very low, due to both inherent limitations in observational studies for inferring causality and concerns for added risk of bias and indirectness in some studies.CONCLUSIONSThe effects of revascularization on cognitive performance in intracranial steno-occlusive disease remain uncertain due to limitations in existing studies. More well-designed randomized trials and observational studies are needed to determine if revascularization can arrest or reverse cognitive decline in these patients.

Depression and Catatonia: A Case of Neuropsychiatric Complications of Moyamoya Disease

Moyamoya disease (MMD) is a rare idiopathic cerebrovascular disease most common among the Asian population. Studies have shown that patients with MMD are at increased risk for developing psychiatric complications. We present a patient with hemorrhagic MMD (RNF213 gene mutation) who developed depression and catatonia over time following MMD-related strokes. While no guidelines exist for the management of such an uncommon scenario, it at least requires an interdepartmental approach. Our report highlights the medical complications of untreated MMD and its neuropsychiatric association with depression and catatonia.

Cerebrovascular Reactivity and Intellectual Outcome in Childhood Stroke With Transient Cerebral Arteriopathy

BACKGROUND

Hypercapnic-challenge blood oxygen level-dependent magnetic resonance imaging cerebrovascular reactivity (CVR), measures the regional perfusion response to altered carbon dioxide. CVR correlates with the tissue-level microvascular dysfunction and ischemic risk. Among children with arterial ischemic stroke, transient cerebral arteriopathy (TCA) is a frequent, nonprogressive unilateral intracranial arteriopathy, which typically results in basal ganglia infarction and chronic cerebral artery stenosis. Therefore TCA provides a model for studying the consequences of chronic nonprogressive stenosis using CVR and intellectual outcome. We hypothesized that children with TCA and chronic nonprogressive intracranial artery stenosis have impaired CVR distal to the stenosis and associated cognitive impairment.

METHODS

We studied children with a prior diagnosis of TCA as defined by infarction limited to the basal ganglia, internal capsule, or both; and significant (greater than 50% diameter) residual stenosis of the supraclinoid internal carotid artery, its proximal branches or both. All children had CVR, intellectual function, and infarct volumes quantified.

RESULTS

We performed CVR studies in five children at mean 8.96 years (3.33 to 14.58 years) poststroke. Impaired CVR was limited to the infarct zone and adjacent white matter in most children. Intellectual function was broadly average in all but one subject.

CONCLUSIONS

In children with typical TCA, ipsilateral cortical CVR and intellectual function seem to be preserved despite persistent arterial stenosis in the majority. These findings suggest that chronic revascularization strategies in these children may not be indicated and require further exploration in a larger cohort of children.

Reduction in Overt and Silent Stroke Recurrence Rate Following Cerebral Revascularization Surgery in Children with Sickle Cell Disease and Severe Cerebral Vasculopathy

BACKGROUND

Children with sickle cell disease (SCD) and moyamoya may benefit from indirect cerebral revascularization surgery in addition to chronic blood transfusion therapy for infarct prevention. We sought to compare overt and silent infarct recurrence rates in children with SCD undergoing revascularization.

METHODS

This was a retrospective cohort study of all children with SCD and moyamoya treated at two children's hospitals. Clinical events and imaging studies were reviewed.

RESULTS

Twenty-seven children with SCD and confirmed moyamoya receiving chronic transfusion therapy were identified, of whom 12 underwent indirect cerebral revascularization. Two subjects had postoperative transient ischemic attacks and another had a subarachnoid blood collection, none of which caused permanent consequences. Two subjects had surgical wound infections. Among these 12 children, the rate of overt and silent infarct recurrence decreased from 13.4 infarcts/100 patient-years before revascularization to 0 infarcts/100 patient-years after revascularization (P = 0.0057); the postrevascularization infarct recurrence rate was also significantly lower than the overall infarct recurrence of 8.87 infarcts/100 patient-years in 15 children without cerebral revascularization (P = 0.025).

CONCLUSIONS

The rate of overt and silent infarct recurrence was significantly lower following indirect cerebral revascularization. A prospective study of cerebral revascularization in children with SCD is needed.

Moyamoya Disease: Epidemiology, Clinical Features, and Diagnosis

Moyamoya disease (MMD) is a chronic, occlusive cerebrovascular disease characterized by progressive stenosis at the terminal portion of the internal carotid artery and an abnormal vascular network at the base of the brain. Although its etiology remains unknown, recent genetic studies identified RNF213 in the 17q25-ter region as an important susceptibility gene of MMD among East Asian populations. Possibly because of genetic differences, MMD is relatively common in people living in East Asian countries such as Korea and Japan, compared to those in the Western Hemisphere. The prevalence of MMD appears to be slightly lower among Chinese, compared to Koreans or Japanese. There are two peaks of incidence with different clinical presentations, at around 10 years and 30-40 years. The peak appears to occur later in women than men. In children, ischemic symptoms, especially transient ischemic attacks, are predominant. Intellectual decline, seizures, and involuntary movements are also more common in this age group. In contrast, adult patients present with intracranial hemorrhage more often than pediatric patients. In patients with MMD, intracerebral hemorrhage is more often accompanied by intraventricular hemorrhage than in patients with hypertensive intracerebral hemorrhage. These different age peaks and different clinical presentations in each age group are also observed in MMD patients in the USA. Catheter angiography is the diagnostic method of choice. Magnetic resonance (MR) angiography and computed tomographic angiography are noninvasive diagnostic methods. High-resolution vessel wall MR imaging also helps diagnose MMD by revealing concentric vessel wall narrowing with basal collaterals.

Cognitive Outcome of Pediatric Moyamoya Disease

Quality of life is the current trend and issue for the most of human diseases. In moyamoya disease (MMD), surgical revascularization has been recognized as the possible assistance to reduce the neurological insult. However, the progressive nature of the disease has been invincible so far. To improve the quality of life of MMD patients not only the protection from the neurological insult but also the maintenance or improvement of cognitive function is inevitable. For pediatric MMD patients, younger age or longer duration of disease is the key factor among the prognostic factors for bad neurological outcomes. Hence, 'the earlier, the better' is the most precious rule for treatment. Protection from neurological insult is very critical and foremost important to improve cognitive outcome. Clinicians need to know the neuropsychological profile of MMD patients for the care of whole person and make an effort to protect the patients from neurological insults to maintain or improve it.

Patterns of cerebral ischemia in children with moyamoya

BACKGROUND

Moyamoya disease is characterized by progressive cerebrovascular stenosis with recurrent cerebral ischemic events. Transient ischemic attacks are often associated with hyperventilation in children with moyamoya, suggesting hypoperfusion rather than thrombotic vaso-occlusion as a prominent mechanism. The patterns of ischemia and severity of steno-occlusive disease in such children may elucidate these mechanisms.

METHODS

Children, 1 month to 18 years, with moyamoya, observed over 11 years were analyzed. A study neuroradiologist reviewed all presurgical neuroimaging. Ischemic injury was categorized into cortical, subcortical, and watershed infarction. Angiographic findings were staged using a standardized method.

RESULTS

Twenty children, 15 girls, median age 6.4 years, were included. All children had magnetic resonance imaging and angiography, and in 16, conventional angiography was available. All 40 hemispheres, in 20 children, were evaluated. The initial clinical presentation included neurological deficits in 17, recurrent transient ischemic attacks in 7, headache in 8, seizures in 8, and alteration in consciousness in 4 children. Infarcts were bilateral in 13 (65%) children (ischemia alone in 14, ischemic stroke with hemorrhagic transformation in two, and primary hemorrhage in two). Infarcts were cortical and/or subcortical in 13 (65%), both deep and cortical watershed in 11 (55%), and cortical watershed alone in 5 (25%) children. The predominant vascular territory involved was the middle cerebral artery. The internal carotid arterial system was involved in all, with stage IV being the most frequent angiographic stage.

CONCLUSIONS

Ischemic injury in deep watershed zones is common in childhood moyamoya and may reflect non-vaso-occlusive ischemic mechanisms. Location and severity of vascular involvement may correlate with various patterns of ischemic infarction in moyamoya disease and requires further study.

Selective neuropsychological impairments and related clinical factors in children with moyamoya disease of the transient ischemic attack type

PURPOSE

Moyamoya disease is characterized by progressive narrowing of bilateral internal carotid arteries. Neuropsychological impairments are suspected due to frequent involvement of the frontotemporal areas. The present study thus aimed to investigate the pattern of neuropsychological function in children diagnosed with moyamoya disease.

METHODS

Thirteen children with moyamoya disease of the transient ischemic attack type received standardized neuropsychological tests that evaluate general intellectual function, verbal comprehension, perceptual organization, working memory, processing speed, episodic memory, category fluency and visuospatial function. Related clinical factors were also analyzed.

RESULTS

The results showed single-domain cognitive impairment in around 15 % of patients and multiple-domain cognitive impairments in 23 % of patients. Selective impairments of episodic memory and processing speed were especially noted in those with younger age of onset and prolonged symptom duration.

CONCLUSIONS

Neuropsychological impairments are not infrequent in children with moyamoya disease despite normal general intellectual functioning. The pattern of cognitive dysfunction is often associated with lesions in frontotemporal areas. Early detection and intervention shall be considered regarding cognitive outcome in pediatric group.

EXAMINER executive function battery and neurologic morbidity in pediatric sickle cell disease

Sickle cell disease (SCD) is blood disorder with a high risk for cerebral vascular morbidities that impact neurocognitive functioning. Specific cognitive abilities are known to be more sensitive to neurologic effects of SCD than IQ scores, yet there is little consensus about which measures to use to assess neurocognitive functioning. We evaluated the ability of the Executive Abilities: Methods and Instruments for Neurobehavioral Evaluation and Research (EXAMINER) Battery to detect neurologic effects in SCD. Thirty-two youth with SCD and sixty demographically-matched comparison youth completed the EXAMINER Battery and selected tests from the Woodcock-Johnson Tests of Cognitive Ability, 3rd edition (WJ-III). Neurologic severity was examined via clinical history for morbidities and midsagittal corpus callosum (CC) area. Results indicated cognitive performance decreased with increasing neurologic morbidity across all cognitive measures; two of four EXAMINER factors were related to CC area. The association with clinical history and midsagittal CC area appeared at least as large for the Examiner Battery scores as for the WJ-III measures. The Examiner Battery showed sensitivity to neurologic history and white matter effects in SCD; this new measure compares favorably to established measures of disease-related neurocognitive effects, but would benefit from further development.

Beyond the definitions of the phenotypic complications of sickle cell disease: an update on management

The sickle hemoglobin is an abnormal hemoglobin due to point mutation (GAG → GTG) in exon 1 of the β globin gene resulting in the substitution of glutamic acid by valine at position 6 of the β globin polypeptide chain. Although the molecular lesion is a single-point mutation, the sickle gene is pleiotropic in nature causing multiple phenotypic expressions that constitute the various complications of sickle cell disease in general and sickle cell anemia in particular. The disease itself is chronic in nature but many of its complications are acute such as the recurrent acute painful crises (its hallmark), acute chest syndrome, and priapism. These complications vary considerably among patients, in the same patient with time, among countries and with age and sex. To date, there is no well-established consensus among providers on the management of the complications of sickle cell disease due in part to lack of evidence and in part to differences in the experience of providers. It is the aim of this paper to review available current approaches to manage the major complications of sickle cell disease. We hope that this will establish another preliminary forum among providers that may eventually lead the way to better outcomes.

Clinical features, prothrombotic risk factors, and long-term follow-up of eight pediatric Moyamoya patients

Background and Purpose

The aim of this study was to elucidate the clinical features, prothrombotic risk factors, and outcome of pediatric Moyamoya patients.

Methods

Patients diagnosed with Moyamoya disease at a tertiary center between January 2000 and December 2006 were enrolled in this study. The clinical presentations, underlying diseases, prothrombotic risk factors, family history of thrombosis, radiological findings, treatment, and outcome of the patients were reviewed retrospectively.

Results

Eight patients with angiographically proven Moyamoya disease were identified, one of whom had neurofibromatosis type I and one had Down syndrome. The age at diagnosis varied between 19 months and 11 years (73.4±41.8 months, mean±SD). The follow-up period after diagnosis was 52.5±14.8 months. In six patients, the initial clinical presentation was hemiparesis. None of the patients had any identifiable prothrombotic factors. Despite medical and surgical treatment, three patients had recurrences and one died. Only two patients recovered without sequelae.

Conclusions

The value of prothrombotic risk factor evaluation appears to be limited in Moyamoya patients; the outcome for pediatric patients remains dismal.

Moyamoya disease: functional and neurocognitive outcomes in the pediatric and adult populations

OBJECT

Moyamoya disease is an occlusive cerebrovascular disorder commonly resulting in neurocognitive impairment. The cognitive outcome parameters commonly affected are intelligence, memory, executive function, and quality of life. In this paper, the authors review the existing literature on cognitive and clinical outcomes in adult and pediatric moyamoya populations separately.

METHODS

A systematic review of the cognitive and clinical outcome literature was performed using the PubMed/MEDLINE database. Outcomes data were contrasted between adult and pediatric populations.

RESULTS

Intelligence is the main cognitive outcome parameter affected in pediatric patients with moyamoya disease, whereas adults most commonly suffer from executive function impairment. Memory has not been studied sufficiently in pediatric patients, and its dysfunction in the adult population remains controversial. Quality of life has not been studied appropriately in either population. Surgical revascularization is the only beneficial treatment option, and a combination of direct and indirect bypass techniques has shown benefit, but the impact on the above-mentioned parameters has not been sufficiently elucidated.

CONCLUSIONS

Moyamoya disease affects the cognition and daily function in pediatric patients to a greater extent than in adult patients. Due to the rarity of the disease, there is a distinct lack of high-level evidence regarding cognitive and clinical outcomes.

Intellectual ability and executive function in pediatric moyamoya vasculopathy

AIM

  Moyamoya vasculopathy is characterized by progressive stenosis of the major arteries of the Circle of Willis, resulting in compromised cerebral blood flow and increased risk of stroke. The objectives of the current study were to examine intellectual and executive functioning of children with moyamoya and to evaluate the impact of moyamoya type, stroke (clinical or silent), vasculopathy laterality, and disease duration on neurocognitive abilities.

METHOD

  Thirty pediatric participants (mean age 10 y 10 mo, SD 4 y; 18 females, 12 males) completed age-appropriate Wechsler Intelligence Scales before any therapeutic revascularization procedures. Reports of executive function were obtained from parents and teachers using the Behavior Rating Index of Executive Function.

RESULTS

  Children with moyamoya scored significantly lower than the test standardization samples on all indices of intelligence and ratings of executive functioning (p<0.001). Patients did not differ by type of moyamoya or history of stroke. Patients with bilateral disease and stroke scored significantly lower than those with unilateral disease on measures of overall intellectual function (p=0.035) and verbal comprehension (p=0.04). Deficits in metacognitive executive functions were also more pronounced in bilateral patients according to teacher ratings.

INTERPRETATION

  Children with moyamoya are at risk for intellectual and executive problems, exacerbated by bilateral disease and clinical stroke history.

A single case report of Moyamoya disease presenting in a psychiatric setting

Moyamoya disease (MMD) is a rare cerebral vasculopathy with limited information on the associated cognitive and emotional sequelae, particularly presenting in a psychiatric setting. We present the case of a 25-year-old female with a history of MMD and depressive disorder. She underwent revascularization surgery following an ischemic stroke at age 15 years. Magnetic resonance imaging at the time of the current assessment revealed markedly abnormal appearance in the anterior cerebral circulation with extensive periventricular collateral vasculature involvement. Neuropsychological assessment data revealed deficits in inhibition and problem-solving, consistent with frontal lobe dysfunction. We discuss the importance of further research on the neuropsychological sequelae of MMD.

Childhood and teenage stroke

OBJECTIVE

The purpose of this manuscript is to review the various etiologies and to discuss the therapeutic issues in childhood stroke.

METHODS

A PubMed search of literature pertaining to childhood stroke was conducted from 1983 to 2008 using specific key search words pertinent to cerebrovascular disorders in childhood.

RESULTS

The analysis of the multiple causes of childhood stroke including arterial ischemic strokes and cerebral venous thrombosis was presented. Current therapy and outcome data in childhood stroke are also discussed throughout the length of the article.

CONCLUSIONS

With increasing vigilance among physicians and improved neuroimaging modalities, the diagnosis of childhood stroke is now made earlier, with increasing frequency and greater accuracy. However, larger and well-controlled studies regarding the optimal management of childhood stroke in terms of the use of both antithrombotic drugs and anticoagulation are still needed in addition to longitudinal follow-up studies of children with stroke.

Moyamoya disease: a clinical spectrum, literature review and case series from a tertiary care hospital in Pakistan

Background

Moyamoya is a rare cerebrovascular disease of unknown etiology. The data on moyamoya disease from Pakistan is sparse. We report a case series of 13 patients who presented with moyamoya disease to a tertiary care hospital in Pakistan with a national referral base.

Methods

We conducted a retrospective review of thirteen patients who presented to The Aga Khan University and diagnosed with "Moyamoya Disease" during the period 1988 – 2006. These patients were identified from existing hospital database via ICD-9 codes. A predesigned questionnaire containing information about clinical presentation, management and neuroimaging was administered to all identified patients.

Results

There were seven males and six females. Mean age at presentation was 16.5 years and a female predominance was found in the pediatric age group (n = 10, 71.4%). Stroke (n = 11, 84.2%) was the most common presentation with motor deficit being the universal cortical symptom. Fever was a common symptom in the lower age groups (n = 4, 51.7%). Cerebral Angiography and Magnetic Resonance Angiography showed bilateral involvement of the vessels in eleven patients while unilateral in two. Subarachnoid and interventricular haemorrhage appeared in 2(15.4%) adults. Twelve (92.3%) patients were discharged as independent with minor deficits regardless of therapeutic modality. Only three (23.0%) patients underwent surgery whereas the remaining were managed conservatively.

Conclusion

Physicians when dealing with childhood strokes and characteristic deficits in adult population should consider Moyamoya disease.

Risk factors for high cerebral blood flow velocity and death in Kenyan children with Sickle Cell Anaemia: role of haemoglobin oxygen saturation and febrile illness

High cerebral blood flow velocity (CBFv) and low haemoglobin oxygen saturation (SpO₂) predict neurological complications in sickle cell anaemia (SCA) but any association is unclear. In a cross-sectional study of 105 Kenyan children, mean CBFv was 120 ± 34·9 cm/s; 3 had conditional CBFv (170–199 cm/s) but none had abnormal CBFv (>200 cm/s). After adjustment for age and haematocrit, CBFv ≥150 cm/s was predicted by SpO₂ ≤ 95% and history of fever. Four years later, 10 children were lost to follow-up, none had suffered neurological events and 11/95 (12%) had died, predicted by history of fever but not low SpO₂. Natural history of SCA in Africa may be different from North America and Europe.

Surgical treatment of moyamoya syndrome in patients with sickle cell anemia: outcome following encephaloduroarteriosynangiosis

OBJECTIVES

Children with sickle cell anemia (SCA) and moyamoya syndrome carry a significant risk of ischemic stroke. Given the success of encephaloduroarteriosynangiosis (EDAS) or pial synangiosis in the treatment of moyamoya disease, the purpose of this study was to examine whether it reliably and durably protected children with SCA and moyamoya syndrome against cerebrovascular complications.

METHODS

The authors retrospectively reviewed a series of 12 patients with SCA who developed clinical and/or radiological evidence of moyamoya syndrome and underwent EDAS.

RESULTS

Eleven patients (92%) presented following a cerebrovascular accident (CVA), transient ischemic attack (TIA), or seizure. Magnetic resonance (MR) imaging or angiography suggested moyamoya vascular changes, and cerebral angiography confirmed the diagnosis in all 12 patients. At the time of surgery, the median age was 12.3 years (range 6.8-19.4 years). Ten (83%) of 12 patients had a history of CVA, and 4 of these patients were compliant with a transfusion protocol at the time of their CVA. Bilateral (7 patients) or unilateral (5 patients) EDAS was performed without complications. The mean follow-up period was 46.8 months (range 8.1-106 months). During the follow-up period, 2 patients (16.7%) suffered cerebrovascular events. One patient, who was stroke-free preoperatively, suffered a CVA 3 weeks after the procedure. The other patient suffered a single left lower-extremity TIA 18 months following right-sided EDAS. She returned to her neurological baseline condition and remains stable 53 months postoperatively. Seven patients underwent follow-up angiography or MR angiography, and evidence of revascularization was noted in all cases. At this time, no patient has developed progressive disease requiring a contralateral procedure after unilateral EDAS.

CONCLUSIONS

The EDAS procedure is a safe and effective treatment option in patients with SCA who develop moyamoya syndrome.

Therapy Insight: stroke risk and its management in patients with sickle cell disease

Children with sickle cell disease, a chronic hemolytic anemia, present with a wide variety of neurological syndromes, including ischemic and hemorrhagic stroke, transient ischemic attacks, 'soft neurological signs', seizures, headache, coma, visual loss, altered mental status, cognitive difficulties, and covert or 'silent' infarction. Those with ischemic stroke usually have stenosis or occlusion of the distal internal carotid and proximal middle cerebral arteries. Indefinite transfusion prevents recurrence in most patients who have had a stroke, and can prevent first stroke in those with high transcranial Doppler velocities. High white cell count, low hemoglobin and oxyhemoglobin desaturation predict neurological complications. Other risk factors for overt ischemic stroke include hypertension, previous transient ischemic attack, covert infarction and chest crisis. For hemorrhagic stroke, aneurysms are common in adults but not children, who often present with hypertension after transfusion or corticosteroids. Seizures are particularly common in patients with cerebrovascular disease and covert infarction; the latter is also associated with hyposplenism and infrequent pain. Factors associated with cognitive difficulties include thrombocytosis, infarction, large-vessel disease, and perfusion abnormality on neuroimaging. As well as investigating the role of genes and the possibility that hydroxyurea or blood pressure control reduce neurological complications, we should explore the modifiable effects of poor nutrition, chronic infection, hemolysis and oxyhemoglobin desaturation on stroke risk.

Physiological correlates of intellectual function in children with sickle cell disease: hypoxaemia, hyperaemia and brain infarction

Lowered intelligence relative to controls is evident by mid-childhood in children with sickle cell disease. There is consensus that brain infarct contributes to this deficit, but the subtle lowering of IQ in children with normal MRI scans might be accounted for by chronic systemic complications leading to insufficient oxygen delivery to the brain. We investigated the relationship between daytime oxyhaemoglobin saturation (SpO2), cerebral blood flow velocity (CBFV) and intellectual function (IQ) using path-analysis in 30 adolescents with sickle cell disease (mean age 17.4 years, SD 4.2). Initial analyses revealed that the association between SpO2 and Full Scale IQ (FSIQ) was fully mediated by increased CBFV, whereby SpO2 was negatively correlated with CBFV and CBFV was negatively correlated with FSIQ, i.e. decreases in oxygen saturation are associated with increases in velocity, and increased velocity is associated with lowered IQ scores. The mediated relationship suggests that lowered IQ may be a function of abnormal oxygen delivery to the brain. Further analyses showed that the association between CBFV and IQ was significant for verbal but not for performance IQ. The pathophysiology characteristic of SCD can interfere with brain function and constrain intellectual development, even in the absence of an infarct. This supports the hypothesis that lowered intellectual function is partly explained by chronic hypoxia, and has wider implications for our understanding of SCD pathophysiology.

Hypoxic adaptation during development: relation to pattern of neurological presentation and cognitive disability

Children with acute hypoxic-ischaemic events (e.g. stroke) and chronic neurological conditions associated with hypoxia frequently present to paediatric neurologists. Failure to adapt to hypoxia may be a common pathophysiological pathway linking a number of other conditions of childhood with cognitive deficit. There is evidence that congenital cardiac disease, asthma and sleep disordered breathing, for example, are associated with cognitive deficit, but little is known about the mechanism and whether there is any structural change. This review describes what is known about how the brain reacts and adapts to hypoxia, focusing on epilepsy and sickle cell disease (SCD). We prospectively recorded overnight oxyhaemoglobin saturation (SpO2) in 18 children with intractable epilepsy, six of whom were currently or recently in minor status (MS). Children with MS were more likely to have an abnormal sleep study defined as either mean baseline SpO2 <94% or >4 dips of >4% in SpO2/hour (p = .04). In our series of prospectively followed patients with SCD who subsequently developed acute neurological symptoms and signs, mean overnight SpO2 was lower in those with cerebrovascular disease on magnetic resonance angiography (Mann-Whitney, p = .01). Acute, intermittent and chronic hypoxia may have detrimental effects on the brain, the clinical manifestations perhaps depending on rapidity of presentation and prior exposure.