Neurovascular disorders have been poorly understood within paediatric neurology and perceived as rare and untreatable. However, clinical and research advances argue for the development of this neurological subspecialty. Key examples are better understanding of risk factors for childhood stroke, recognition of cerebrovascular complications of genetic disorders, and the potential for multimodal therapy for complex cerebrovascular disease.
Arterial ischaemic stroke (AIS) in adults is now a medical emergency; however, the distinct causes and consequences in children make adult ‘stroke pathways’ (e.g. for hyperacute thrombolysis) inappropriate for most children. The significant delays in diagnosis of childhood AIS reflect lack of clinical awareness and access to acute neuroimaging – the latter is essential because of the wide differential diagnosis. Management of childhood stroke is supported by international clinical guidelines,1 but these also reflect the urgent need for high quality research to underpin recommendations, currently based on expert consensus. Specialist clinical expertise can help to target investigations and potential interventions in individual children, as these are much more diverse than in adults. The International Pediatric Stroke Study group (https://app3.ccb.sickkids.ca/cstrokestudy/) has provided key insights into childhood stroke and developed an important collaborative research framework. International networks, such as the International Child Neurology Association (ICNA; http://www.icnapedia.org), have an important role in facilitating clinical and research infrastructure, as well as the resources to consider global variations in disease profiles and medical practice.
Sickle-cell disease is one of the most common severe monogenic disorders; a quarter of affected people will have ischaemic brain injury in childhood. Transcranial Doppler ultrasound (TCD) screening, and prophylactic blood transfusion if this is abnormal, is effective in AIS prevention2 and is being implemented in many countries. The UK National Institute for Health and Clinical Excellence (NICE) guidelines (http://sct.screening.nhs.uk/cms.php?folder=2493) recommend neuroimaging in children with abnormal TCD studies, as well as those with a range of neurological symptoms. Interpretation of neuroimaging in sickle-cell disease and putting this into an appropriate clinical context is complex, and argues for involvement of a child neurologist. Other neurological issues include assessment for surgical revascularization, concurrent cerebrovascular pathologies (including dissection3), and AIS risk factors.
The issue of cerebrovascular screening in asymptomatic children with genetic disorders is complex and contentious. Examples include children whose parents have hereditary haemorrhagic telangiectasia4 (frequency 1:5 000) and microcephalic osteodysplastic primordial dwarfism type II – even where there are guidelines, the evidence underpinning these is scanty. The ethical and health economic issues merit separate consideration; however counselling, imaging, and managing such patients and their cerebrovascular disease is complex, requiring specialist expertise and access to a multidisciplinary neurovascular team.
The literature on treatment of paediatric brain arteriovenous malformations is strongly biased by proponents of specific treatment approaches (surgical resection/endovascular treatment/stereotactic radiosurgery) and it is impossible to derive conclusions about relative efficacy or factors influencing this. Increasing realization that vascular malformations are commonly genetic or systemic means that a detailed clinical assessment and identification of medically treatable factors is essential. In this regard the neurologist can act as an honest broker in the multidisciplinary forum. Excitingly, genetic advances have elucidated some underlying disease mechanisms and targeted medical interventions are likely to become available in the palpable future.5 Rapid developments in endovascular devices (stents/angioplasty) mean that the neurologist within such teams also has a key role in identifying children with occlusive cerebrovascular diseases who could benefit from these novel interventions, akin to established practice for evaluating children with moyamoya for surgical revascularization.
Organizations such as ICNA, are key to achieving improvements in clinical care and facilitating research on paediatric neurovascular disorders on a global scale. In the upcoming May 2012 ICNA meeting in Brisbane (http://www.icnc2012.com) there will be four neurovascular sessions, including 11 lectures from an international faculty, promoting both clinical and research agendas. Paediatric neurovascular disorders are clinically significant and now often treatable. The development of networks, that include specialist multidisciplinary teams to consider complex or novel interventions and systematically accrue high quality clinical evidence is an essential requirement.