Keywords paediatric stroke - management - risk factors - symptoms
Schlüsselwörter Schlaganfall - Pädiatrie - Symptome - Risikofaktoren - Therapie
Introduction
With an incidence of 1–8/100,000 children per year, childhood stroke is rare, but causes significant morbidity and mortality.[1 ]
[2 ]
[3 ]
[4 ] It can occur at any age with incidence peaks in infants, toddlers and adolescents with a significant male predominance in the latter age group. Low awareness for childhood stroke among parents and health care providers, in-hospital delay in proper diagnostic/imaging and the broad list of more likely “stroke mimics” lead to an average time gap of 24 hours between clinical onset of symptoms and diagnosis.[5 ]
[6 ]
The following review provides an overview of clinical presentation, risk factors and management of childhood arterial ischaemic stroke (AIS) in infants, children and adolescents (>28 days of life to ≤18 years).
Clinical Presentation
Independent of age, the majority of children present with an acute focal neurological deficit such as acute hemiparesis, facial palsy and speech disturbance.[4 ]
[5 ]
[7 ]
[8 ]
[9 ] Therefore, the “Face Arm Speech Time—FAST test”—developed as an early recognition tool for adult stroke, can also be used as a screening tool in childhood stroke with a satisfactory sensitivity of approximately 76%.[10 ] The sensitivity of the beFAST test (b = balance, e = eyes) may be even higher but has not been evaluated systematically so far. There are, however, some additional age-specific clinical features which might complicate the diagnosis of childhood stroke, like the initial presentation with seizures especially in infants and very young children (up to approximately 50%) and headache in school children and adolescents (approximately 30%).[4 ]
[7 ]
[11 ]
[12 ]
[13 ] A stuttering course is described especially in children with intracranial arteriopathy, either transient or chronic (sickle cell disease, moyamoya, etc.). In general, it should be noted that the younger the child, the more nonspecific the clinical presentation of ischaemic stroke can be. To increase awareness for stroke in children, the paediatric stroke working group of the Ludwig-Maximilians-University Munich developed a pocket card for paediatricians called MERCS (Munich Early Recognition of Childhood Stroke) highlighting the beFAST test and additional information for both ischaemic and haemorrhagic stroke ([Fig. 1 ]).
Fig. 1 Pocketcard MERCS—Munich Early Recognition of Childhood Stroke. Besides the stroke recognition tool beFAST on the top, it provides relevant clinical information about both childhood ischaemic and haemorrhagic stroke on the front and back side of the card. (Front: childhood ischaemic stroke: well in the week before presentation? Seizures? Headache? Back: consider haemorrhagic stroke: headache “sudden”; “worst”; vomiting; decreased level of consciousness). A structured emergency examination for time-critical neurological disorders is also illustrated: level of consciousness? Speech? Understands and follows instructions? Meningism I Neck stiffness? Facial palsy? Coordination? Visual disturbance? Hemiparesis? Tendon reflexes? Walking I Balance? There is additional free space on the back side for hospital-specific emergency telephone numbers.
Besides additional nonspecific clinical presentation, also well-known and more frequently occurring “stroke mimics” like complex migraine, seizures or idiopathic facial palsy could delay the diagnosis of childhood stroke.[11 ]
[14 ]
[15 ]
Risk Factors
The main risk factors for ischaemic stroke in adults like atrial fibrillation, arterial hypertension or diabetes mellitus are not relevant in childhood stroke. A large number of different risk factor categories need to be considered in the diagnostic work-up of children and adolescents like cardiac diseases, arteriopathies, infections, prothrombotic states, metabolic or other genetic diseases.[4 ]
[7 ]
[16 ]
[17 ]
[18 ]
[19 ] An overview of possible risk factor categories and examples within the categories are listed in [Table 1 ].
Table 1
Possible risk factors in childhood AIS, adapted from Gerstl et al[19 ]
Arteriopathy
Transient cerebral arteriopathy
Primary CNS vasculitis
Para-/post-infectious vasculitis
Arterial dissection (extra-/intracranial)
Moyamoya angiopathy
Fibromuscular dysplasia
Systemic lupus erythematosus
Other
Infectious disease
Varicella zoster virus, Borrelia burgdorferi , mycoplasma pneumonia, enterovirus, parvovirus, herpes simplex virus, other
Meningitis (Streptococcus pneumoniae , mycobacterium tuberculosis)
In general: sepsis, dehydration
Cardiac
Congenital/acquired heart disease
Patent foramen ovale
Endocarditis
Cardiomyopathy
Previous cardiac surgery/catheterization
Mechanical circulatory support
Arrhythmia
Other
Prothrombotic state
Protein C deficiency
Protein S deficiency
Prothrombin mutation (G20210A)
Factor V Leiden (G1691A)
MTHFR (C677T)
Hyperhomocysteinaemia
Elevated lipoprotein (a)
Antithrombin deficiency
Increased factor VIII (permanently >150%)
Lupus anticoagulants and antiphospholipid antibody syndrome
Haemato-oncological
Sickle cell disease
Haemolytic anaemia
Other
Genetic predisposition
Trisomy 21
Neurofibromatosis type 1
PHACE syndrome
Mutation: ACTA2, ADA2 (CECR1 gene), SMAD3, Col4A1, Col4A2
Metabolic
Mitochondriopathy
Fabry disease
Homocystinuria
CDG syndrome
Other
Other
Medication/therapy (oral contraceptives, radiation, etc.)
Connective tissue disorders (Ehlers–Danlos syndrome, Marfan syndrome, osteogenesis imperfecta)
Cerebrovascular anomalies (aneurysm, arteriovenous malformation, cavernoma)
Brain tumour
Previous neurosurgical procedure
Migraine
Abbreviations: AIS, arterial ischaemic stroke; CDG, congenital disorders of glycosylation; CNS, central nervous system.
Childhood stroke is known to be a multiple-risk disease, meaning that in a relevant proportion of the affected children the presence and interaction of different risk factors lead to the ischaemic stroke—a fact which also seems to worsen outcome.[20 ]
[21 ] In 10 to 20% of children, so far no known risk factor hasbeen detected in a thorough diagnostic work-up and stroke is therefore classified as “cryptogenic”.
The Childhood AIS Standardized Classification and Evaluation (CASCADE) criteria, established in 2012 as a comprehensive classification system, allows a uniform nomenclature and classification in childhood AIS.[22 ]
[23 ] CASCADE classification on admission was also shown to be associated with risk of stroke recurrence and with different courses of the arteriopathy.[24 ] The primary (acute/chronic) and secondary CASCADE criteria are summarized in [Table 2 ].
Table 2
CASCADE criteria, adapted from Bernard et al[22 ]
[23 ]
Primary classification (only one selected)
Basic subtype (7)
Expanded subtype (19)
1. Small vessel arteriopathy in childhood
2. Unilateral focal cerebral arteriopathy in childhood
3. Bilateral focal cerebral arteriopathy in childhood
4. Aortic/cervical arteriopathy
5. Cardioembolic
6. Other
7. Multifactorial
Further classification of basic subtypes
Secondary classification (select as many as apply)
1. Genetic: vasculopathy
2. Infectious
3. Haematological/thrombotic
4. Inflammatory
5. Genetic: metabolic
6. Drug/toxin exposure
7. Vasospasm
Arteriopathies
Arteriopathies are one of the leading causes of childhood stroke (up to 50%) and, furthermore, are a strong predictor of recurrent stroke.[4 ]
[18 ]
[25 ] The most common are the focal cerebral arteriopathy (up to 30%), the cerebrovascular dissection (up to 10%) and the Moyamoya angiopathy. With the progress in genetic testing and knowledge, arteriopathies on the basis of a genetic disorder are more and more diagnosed.[26 ]
Transient Cerebral Arteriopathy (Synonyms: Transient Focal Arteriopathy, Focal Cerebral Arteriopathy)
This unilateral arteriopathy mostly affects the distal internal cerebral artery, the proximal middle cerebral artery or the proximal anterior cerebral artery.[27 ]
[28 ]
[29 ]
[30 ] Though transient cerebral arteriopathy (TCA) shows a self-limiting course without progression after 6 to 12 months, a rapid aggravation in the first days to weeks is possible and responsible for a high risk of recurrent stroke in this phase. The pathophysiology is not completely understood, but a post-/parainfectious inflammatory process of the vessel wall is considered being responsible for swelling and subsequently for occlusion of the vessel. Post-varicella-arteriopathy is the most known reason for a TCA and can occur weeks to months after the acute infection with varicella zoster virus.[31 ]
[32 ] Still, other infectious pathogens such as herpes simplex virus, Borrelia burgdorferi or enterovirus should also be checked for.
[Fig. 2 ] shows typical magnetic resonance imaging (MRI) findings in TCA with narrowing and irregularity of the affected vessel ([Fig. 2A ]) and contrast enhancement of the vessel wall as a sign for the active inflammatory process ([Fig. 2B ]).
Fig. 2 Five-year old boy with TCA. (A ) Three-dimensional time-of-flight magnetic resonance angiography image with a focal severe stenosis and irregularity of the right middle cerebral artery (MCA;white arrows ) and milder irregularity of the right anterior cerebral artery (A1 segment;white asterisk ). (B ) Contrast-enhanced black blood vessel wall imaging shows a vessel wall enhancement of the right MCA (white arrows ) (asterisk : right basal ganglia infarction). TCA, transient cerebral arteriopathy.
Cerebrovascular Dissection
Dissections are a relevant cause for childhood stroke and are mainly triggered by (trivial) trauma during sports or playing activities.[18 ]
[33 ] Predisposing factors may be genetic connective tissue disorders like Marfan syndrome or Ehlers–Danlos syndrome, but also arteriopathies leading to vulnerable vessel walls are considered to be a relevant risk factor. The differentiation from intracerebral dissections to focal cerebral arteriopathies may be challenging.[34 ]
Moyamoya Angiopathy
Moyamoya angiopathy is a cerebrovascular disease with a progressive narrowing of the distal internal cerebral artery or middle cerebral artery leading to compensatory collaterals described in angiography as the characteristic “puffy smoke”.[35 ] Moyamoya can be primary (idiopathic) or secondary to other underlying disorders such as sickle cell disease, trisomy 21 or neurofibromatosis. Knowledge about genetics underlying Moyamoya angiopathy [e.g.,Ring finger 213 (RNF213) gene ] is increasing, as is about related changes in circulating factors and the response to environmental factors.[36 ]
Arteriopathies with a Genetic Predisposition
Under certain circumstances, a work-up for genetic arteriopathies is reasonable: these could be the co-occurrence of ischaemic and haemorrhagic strokes (in the child or in the family) or the presence of almost pathognomonic additional symptom combinations like recurrent fever with livedo racemosa and hepatosplenomegaly in ADA2 deficiency.[26 ] Some other known mutations leading to ischaemic strokes are listed in [Table 1 ].
Infectious Diseases
Infectious diseases are an important risk factor for childhood AIS and could be one reason for the incidence peak in infants and very young children. Even “minor infections” like upper respiratory tract infections or otitis media have been shown to increase the risk for ischaemic stroke up to sixfold.[37 ]
[38 ]
[39 ] Ischaemic stroke is also a known complication in bacterial or tuberculous meningitis. In general, a broad list of infectious pathogens can trigger the above-described transient focal arteriopathy leading to a stroke.
Cardiac Diseases
Cardiac diseases are one of the top causes for childhood stroke. These include congenital heart diseases, cardiomyopathies, endocarditis, cardiac surgery or cardiac catheter examination and mechanical circulatory support.[4 ]
[17 ]
[40 ] A paradoxical embolism from a patent foramen ovale as a single cause of an ischaemic stroke in children remains a diagnosis reached by an exclusionary process.[41 ]
Prothrombotic States
The influence of prothrombotic risk factors in the etiology of childhood stroke is well described and differs from the prothrombotic risk factor itself, an isolated versus combined occurrence and the co-existence of further, non-prothrombotic risk factors.[42 ]
[43 ]
Diagnosis
Imaging
A cranial MRI is described to be the gold standard in the diagnosis of childhood AIS with its obvious potential in the proof of a recent stroke as well as in the differentiation to the multiple, more common stroke mimics. A short, lasting 10 to 20 minutes, hyperacute MRI protocol is recommended to make the initial diagnosis leading to the hyperacute management.[6 ]
[12 ]
[44 ]
[45 ] This rapid MRI should include the following sequences:
Diffusion-weighted imaging and apparent diffusion coefficient.
Susceptibility-weighted imaging.
Cervical and cerebral three-dimensional time-of-flight magnetic resonance angiography.
Fluid-attenuated inversion recovery.
Follow-up MRIs include further sequences and, considering the high incidence of arteriopathies in childhood AIS, should also focus on a proper vessel wall imaging.[25 ]
If initial cranial MRI imaging would not be feasible within a short time due to any circumstances, initial diagnosis is done with a cranial computed tomography (CT) as it is in a critically ill child with a reduced level of consciousness. But one should keep in mind its lower sensitivity in the early hours after stroke and regarding stroke mimics compared with an initial MRI as well as the diagnostic limits concerning the posterior fossa. The radiation exposure is a further argument for the restricted use of a CT in children.
A conventional angiography may be necessary in the post-acute setting in some children for further etiological work-up or treatment planning (e.g., in children with Moyamoya). Transcranial color-coded sonography is regularly recommended in patients with sickle cell disease (the most frequent risk factor for childhood stroke worldwide) and may also be helpful in monitoring of cerebral arteriopathies.[46 ]
Further Diagnostics
With respect to the broad list of possible risk factors and childhood AIS as a multiple-risk disease, the authors recommend basis laboratory testing for each child including screening for infectious diseases, vasculitis, prothrombotic risk factors, metabolic diseases, etc. In some cases (see above), genetic testing may also be indicated. An echocardiography and electrocardiogram are also part of the basis work-up in childhood stroke. The extended diagnostic work-up depends amongst others on medical history, results of neuroimaging, CASCADE classification and any further etiological hints.[47 ]
[48 ]
Management
Thrombolysis and Mechanical Thrombectomy
So far, there are no published clinical trials investigating efficacy and safety of thrombolysis and mechanical thrombectomy in childhood AIS. The Thrombolysis in Paediatric Stroke Study (TIPS), created as an international multicentre, dose-adaptive cohort study, has been closed in 2013 because of unsuccessful recruitment—which underlines the probably insurmountable difficulties of conducting randomized clinical trials in childhood stroke.[49 ] The results of several randomized open-label placebo-controlled endovascular trials in adult stroke, using newer generation clot retrieval devices, cannot be directly transferred to the paediatric population due to the above-mentioned different aspects.[50 ]
[51 ]
[52 ]
[53 ]
[54 ] Therefore, the decision for intravenous thrombolysis or an endovascular therapy as an “off-label” therapy must be made as a case-by-case decision by a multidisciplinary team in specialized (paediatric) stroke centres after a thorough risk–benefit analysis. However, there has been an increasing number of published case reports and case-series describing thrombolysis and endovascular therapy as a feasible and promising treatment option even in very young children.[55 ]
[56 ]
[57 ]
[58 ]
[59 ] The recently published results of the Save ChildS Study, investigating feasibility, safety and outcome of endovascular recanalization of childhood AIS, are encouragingly positive.[60 ] In this retrospective, multicentrecohort study on 73 children treated in 27 international stroke centres, the safety profile of mechanical thrombectomy was comparable to those in randomized clinical trials for adults and outcome of most of the treated children was favourable.
Antithrombotic Therapy
If thrombolysis and thrombectomy are no treatment options, initial antithrombotic therapy is started with unfractionated heparin, low-molecular-weight heparin or acetylsalicylic acid (ASA), which may be switched after etiological classification.[47 ]
[48 ]
[61 ]
[62 ] In children with cardioembolic stroke or a stroke caused by a cervical arterial dissection, low–molecular-weight heparin or Vitamin K antagonists are recommended, whereas children with other underlying etiologies should be treated with ASA.[63 ] So far, direct oral anticoagulants are not licensed for the use in children. An overview of the most common antithrombotic agents is shown in [Table 3 ].[64 ] The treatment duration depends on the underlying condition, the risk of recurrent strokes and imaging results.[47 ] Most children are treated for at least 2 years.
Table 3
Overview of the most common antithrombotic agents, adapted from Kurnik et al[64 ]
Antithrombotic agent
Dosage
Unfractionated heparin
(100)–300–600 U/kg/d
or rather: 50 U/kg as a bolus over 10 min, then: < 1y : 20–30 U/kg/h, >1y : 20–25 U/kg/h
target : PTT (50)–60–85s, Antithrombin should be 60–80%
LMWH
Enoxaparin:
<2 mo
[a ]: 1.5 mg/kg 1–2 ×/d sc (0.75 mg/kg as prophylaxis)
>2 mo
[a ]: 1.0–1.5 mg/kg 1–2 x/d sc (0.5 mg/kg as prophylaxis)
Dalteparin: 100–150–200 U/kg/d sc
Acetylsalicylic acid
(1–)3–5 mg/kg/d (max: 100 mg/d)
Clopidogrel
1 mg/kg 1 ×/d
Phenprocoumon
Day 1: 0.2–0.3 mg/kg/d
Day 2: 50% of the initial dosage
From day 3: adjust according to INR
Warfarin
Day 1: 0.2 mg/kg 1 ×/d p.o.
From day 2: 0.05–0.2 mg/kg 1 ×/d p.o. (adjust according to INR)
Abbreviations: INR, international normalized ratio; LMWH, low-molecular-weight heparin;p.o., orally; PTT, partial thromboplastin time;sc, subcutaneously.
a In clinical practice, not only infants <2months need higher dosages of LMWH, an adjustment according to target anti-FXa levels is obligatory.
To standardize and optimize the use of antithrombotic therapy in childhood AIS, further studies with a focus, amongst others, on efficacy, dosing, impact of developmental haemostasis, treatment monitoring and duration are needed.[65 ]
Steroids/Immunosuppressive Therapy
In patients with primary small or large vessel central nervous system vasculitis, steroids and in some cases further immunosuppressive therapy are well established.[12 ] In a retrospective study, the addition of steroids to antiplatelet therapy showed some positive effects in children with transient focal arteriopathy, but this benefit has to be proven in larger clinical trials.[66 ]
Risk of Recurrence/Outcome
Risk of Recurrence/Outcome
The risk of recurrence is between 6 and 40%, but depends on each child's individual risk factor profile.[7 ]
[67 ]
[68 ] Children with no or a single known risk factor have a substantially lower risk of recurrence than children with multiple risk factors. The highest risk of recurrence is described in children with some stenosing arteriopathies like Moyamoya angiopathy or with sickle cell disease. With respect to prothrombotic risk factors, an elevated lipoprotein (a), a heterozygous antithrombin deficiency and the presence of more than one prothrombotic risk factor are independently associated with an increased risk of AIS recurrence.[69 ]
Physical and motor impairments (especially hemiparesis with post-stroke spasticity) are common and affect almost two-thirds of childhood stroke patients. Larger cortical lesions and the occurrence of acute seizures (as presenting symptom) or seizures in the early post-stroke period (within 24–48 hours) significantly increase the risk for a post-stroke epilepsy, which develops in 13 to 24% of the children.[70 ]
[71 ]
[72 ] Lower health-related quality of life was demonstrated in childhood stroke survivors compared with the reference population.[73 ] Follow-up care after childhood AIS should include all bio-psycho-social aspects and should therefore also focus on further life-changing sequela like fatigue, attention deficits, cognitive decline and psychiatric comorbidities, and last but not least the burden of stroke suffered by the whole family of the affected child.
Conclusion
Childhood AIS is an emergency—Time is brain!
Fortunately, there has been a considerable effort to improve management of childhood AIS over the last few years: raising awareness for childhood stroke, developing childhood stroke recognition tools, the implementation of paediatric stroke protocols with quick access to proper neuroimaging and increasing experience in endovascular treatment are just a few illustrating examples. Facing the difficulties of conducting large randomized controlled trials in childhood AIS and produce robust evidence, paediatric neurovascular teams should be encouraged to collaborate in paediatric stroke networks, nationally and internationally, to increase knowledge about this rare disease with all its complexity.
