Paediatric Medicine - Childhood stroke

Dr Andrew Mallick and Dr Finbar O'Callaghan discuss the causes and impact of stroke in paediatric patients.

The mainstays of treatment after ischaemic stroke is aspirin or heparin (Photograph: SPL)
The mainstays of treatment after ischaemic stroke is aspirin or heparin (Photograph: SPL)

Stroke is one of the leading causes of death and disability in adults. However, there is poor recognition by the public and health professionals that stroke is also an important condition in childhood.

Stroke affects around 400 children per year in the UK and in developed nations is one of the top 10 causes of childhood death. Children surviving stroke have a high risk of disability and there is a high risk of recurrence.

Aetiological factors
Ischaemic and haemorrhagic stroke occur roughly equally in children. The causes of childhood stroke are varied and very different to those associated with adult stroke.

A large proportion of children with ischaemic stroke are found to have abnormalities of their cerebral vasculature, such as focal stenosis of large or medium vessels or arterial dissection.

In the majority of cases, the cause of the cerebral vasculopathy is unclear, although there is increasing evidence linking infection to the development of vessel stenosis. Other important causes of ischaemic stroke in children are underlying congenital heart disease and sickle cell disease.

There is interest in the role of inherited thrombophilias but, thus far, their association with childhood stroke has been found to be relatively weak.

The majority of children with haemorrhagic stroke have an intracerebral structural lesion, such as an arteriovenous malformation or an arterial aneurysm.

Haematological disorders, such as haemophilia and thrombocytopaenia can also lead to haemorrhagic stroke.

Presenting features
The most common presenting features of stroke in children are focal weakness or hemiparesis, seizures, altered level of consciousness or mental state, dysphasia, cerebellar signs, headache and vomiting. Infants are more likely than older children to present with seizures or altered conscious level.

Despite the presenting features being similar to those of adult stroke the time to diagnosis is typically much longer in children. The median time from onset of symptoms to presentation to a health professional is around six hours and the median time from presentation to initial neuroimaging is a further six hours.

Almost half of children eventually diagnosed with stroke are initially given a different diagnosis, such as migraine, postictal hemiparesis, acute disseminated encephalomyelitis, encephalitis, brain tumour, cerebral abscess, drug intoxication or psychogenic illness.

The symptoms of stroke in children are non-specific and in many cases stroke can only be reliably differentiated from conditions that mimic stroke by neuroimaging. As such, all children presenting with acute onset neurological signs should be urgently referred for paediatric assessment.

There is very little evidence relating to childhood stroke upon which to base management decisions. There are a number of published clinical guidelines, although their recommendations are largely based on expert consensus and extrapolation from adult data.

Diagnosis
Neuroimaging, preferably with MRI, is mandatory to make the diagnosis of stroke in a child as the differentials are so varied.

Imaging is also key to defining the stroke subtype and is an important tool in establishing aetiological factors.

Due to the high prevalence of cerebral vasculopathy, imaging of the cerebral vasculature using magnetic resonance angiography or conventional angiography is increasingly used in childhood stroke.

Echocardiography is also frequently used to investigate possible cardiac abnormalities.

Typically, a wide variety of laboratory investigations are employed to investigate other possible aetiological factors such as inherited thrombophilias and infectious agents.

Acute care and secondary prevention
As there is no current evidence to support the use of specific neuroprotective measures in the acute setting, best practice is to maintain temperature, BP, oxygen saturations, blood glucose and hydration within normal limits. Seizures should be actively treated.

The mainstay of specific treatment following arterial ischaemic stroke is aspirin or heparin. Aspirin or anticoagulation with low molecular weight heparin or warfarin are usually used as secondary prevention measures. Therapies specific to the aetiology may also be used to reduce the risk of recurrence, such as blood transfusions for sickle cell disease.

Although there is interest relating to hyperacute therapies, in thrombolysis with tissue plasminogen activator, no such therapy has been evaluated in children in a clinical trial and they are not recommended for use in childhood stroke.

Around a third of children with haemorrhagic stroke will require neurosurgical haematoma evacuation and most of those with an underlying vascular malformation will need definitive management of their lesion.

Rehabilitation and outcome
Following the acute phase, rehabilitation is a very important aspect of management.

Children who have had a stroke frequently require a range of therapies such as physiotherapy, occupational therapy and speech and language therapy.

Children may also have additional educational needs.

Current evidence suggests at least half of children who survive stroke have impairments that significantly interfere with daily life. Only around one in five survivors have no impairments at follow-up.

Sensorimotor deficits (in particular hemiplegia) are the most frequently occurring impairments although deficits can often be found in language, cognitive and behavioural domains. Following stroke, children are at increased risk of epilepsy, ADHD and psychiatric disorders.

The past decade has seen a burgeoning interest in childhood stroke. There is now a number of national and international research collaborations as well as some dedicated clinical services in children's hospitals.

Key issues to be addressed over the next decade include improving the recognition of childhood stroke and increasing the evidence base upon which management decisions can be based.

  • Dr Mallick is paediatric neurology research associate and Dr O'Callaghan is consultant senior lecturer in paediatric neurology at the University of Bristol

Resources
1. Mallick AA, O'Callaghan FJ. The epidemiology of childhood stroke. Eur J Paediatr Neurol 2010; 14(3): 197-205.

2. Cnossen MH, Aarsen FK, van den Akker SL et al. Paediatric arterial ischaemic stroke: functional outcome and risk factors. Dev Med Child Neurol 2010; 52(4): 394-9.

3. Blom I, De Schryver EL, Kappelle LJ et al. Prognosis of haemorrhagic stroke in childhood: a long-term follow-up study. Dev Med Child Neurol 2003; 45(4): 233-9.

4. Paediatric Stroke Working Group. Stroke in childhood: clinical guidelines for diagnosis, management and rehabilitation. London: Royal College of Physicians, Clinical Effectiveness and Evaluation Unit, 2004.

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