Stroke in Children

Introduction

There are various types of stroke in children, including arterial ischemic strokes, venous infarctions due to venous sinus thrombosis, intracerebral hemorrhages, and subarachnoid hemorrhages. Stroke is a relatively rare occurrence in children, but can lead to significant morbidity and mortality, and is one of the top 10 causes of death in children aged 1–18 years . It is important to be aware of the fact that children with strokes present differently than adults, and that the clinical symptoms can vary, depending on the age of the child . Children also have risk factors for stroke that are less common than in adults, thus the cause of stroke differs considerably with age. Two main age groups can be distinguished: perinatal/neonatal (week 22 of pregnancy to 1 month of life), and children aged 1 month to 18 years. Each of these groups has different frequencies of stroke etiologies. Additionally, the cause of stroke in these groups also does vary depending on geographical, economic, and environmental factors. For example, tuberculous meningitis is an important cause of pediatric stroke in India, but is unusual in the USA .

Epidemiology

A stroke in children is typically considered to be a relatively rare event. The reported incidence of combined ischemic and hemorrhagic pediatric stroke ranges from 1.2 to 13 cases per 100,000 children under 18 years of age . However, pediatric stroke is likely more common than we may realize, as it is thought to be frequently undiagnosed or misdiagnosed. This may be due to a variety of factors including a low level of suspicion by the clinician or due to patients who present with subtle symptoms that mimic other diseases. This, in turn, can lead to a delay in the diagnosis . Boys are more likely to have a stroke than girls, even after controlling for differences in frequency of causes such as trauma . Additionally, African American children are more at risk compared to Caucasian and Asian children, and this difference remains true even after accounting for sickle cell disease (SCD) patients with stroke .

Perinatal and Neonatal Stroke

As mentioned before, perinatal stroke is often undiagnosed or misdiagnosed due to the subtleness of signs and symptoms. As a result, the incidence of perinatal stroke is only an estimate. Ischemic stroke is anticipated to occur in about 1:3500 of live births, and hemorrhagic stroke in about 1:16,000 live births . Of the identified perinatal strokes, about 80% are ischemic arterial strokes and the remaining 20% are due to either cerebral venous sinus thrombosis or primary brain hemorrhage . The critical period in the pregnancy for stroke is the end of the second trimester and the entire third trimester . Obvious signs of stroke may be observed within hours to days of birth. Acute symptoms of neonatal stroke can include seizures, periods of apnea with staring, coma/listlessness, focal weakness/hemiparesis, or other focal deficits . Perinatal strokes are most likely to initially present with focal seizures or lethargy in the first few days after birth . Seizures are quite common acutely, occurring in up to 75%. Typically the seizures are focal, mainly involving only one extremity .

Specific types of stroke will also present differently depending on the age of the child . For example, cerebral venous sinus thrombosis can present in all ages with fever and lethargy, but young infants can also have decreased oral intake or respiratory distress as their initial symptoms. Physical examination of the infant may reveal dilated scalp veins, eyelid swelling, or a large anterior fontanelle, whereas an older child would likely present with slowly progressive signs, such as vomiting, headache, or other phenomena associated with increased intracranial pressure. A subarachnoid hemorrhage can also present as irritability and a bulging fontanelle in infants, whereas older children may instead complain of sudden acute headache, neck pain, or photophobia .

Unfortunately, especially in neonatal stroke, there can be a delay in recognizing the event. Subtle signs may not be observed in the newborn period, and symptoms may only be identified as the child grows and develops over the first year. One of the most common signs found in a child with a prior neonatal stroke is a hand preference, consistently reaching out for objects with only one hand before the age of 1 year. Missed developmental milestones, unilateral weakness/hemiparesis, later development of seizures, or the presence of another focal deficit can all be clues that a perinatal stroke occurred previously .

Etiology of stroke in neonates can be complex and may be due to a combination of factors, including cardiac disorders, coagulopathy, infection, trauma, maternal medications and toxins, maternal placenta disorders, and intrauterine or perinatal asphyxia . Neonatal ischemia is often caused by cardiac disease, sepsis with vascular collapse, and hypertension. Heart abnormalities in the fetus, as well as hypoglycemia and twin-to-twin transfusion syndrome are conditions in which arterial strokes are more prominent. Additionally, hypoxic–ischemic injury is also relatively common in neonates, and can be caused by intrauterine asphyxia, birth-related problems, uterine and placental abruption, respiratory insufficiency after birth (such as with meconium aspiration), recurrent apnea, hyaline membrane disease in premature infants, and severe congenital heart disease . The most vulnerable areas for hypoxic–ischemic injuries are the cerebral cortex, particularly the hippocampi, as well as the cerebellar cortex and pontine nuclei in the brainstem. On neuroimaging, observable lesions are most commonly noted in the parasagittal regions, deep periventricular white matter, and within the basal gangli/thalami .

The vast majority of lesions in premature infants are located within the periventricular white matter. Premature infants are also susceptible to developing brain hemorrhages, including germinal matrix hemorrhages that usually occur either in the periventricular region with spread into the adjacent ventricle or in the cerebellum. Most germinal matrix hemorrhages occur during the first 3 postnatal days, especially during the first hours . Significant subdural and subarachnoid bleeding can also occur with more severe birth trauma or coagulopathy .

In most cases, the cause of perinatal stroke remains unknown. Parents should be counseled that the risk of having another child with perinatal stroke is extremely low, with recurrent stroke risk being <1% . It is also very important for mothers to know that there is usually nothing they did or did not do during their pregnancy that caused their child’s stroke .

Stroke in Children

As with stroke in neonates, childhood stroke may be missed due to a lack of awareness that stroke can occur at any age, but it also can be misdiagnosed. Perhaps in part this is because stroke in children can present very differently depending upon the individual. Childhood stroke is estimated to occur in about 1.2–13 per 100,000 children per year . For children who have a first stroke between 1 month and 18 years, the risk of recurrent stroke is 15–18% . Children with cardiac disease can have up to a fivefold increased recurrence risk as compared to children without cardiac disease . In children with stroke, 50% are ischemic, with hemorrhages comprising the remaining 50%, which is very different from neonates and from adults.

Children and adolescents with stroke may have atypical presentations when compared with adult patients . Symptoms of childhood stroke include sudden or gradual focal numbness or weakness, sudden loss of vision or diplopia, sudden confusion or speech difficulty, new onset seizures, diminished level of consciousness, or sudden severe headache associated with vomiting or sleepiness . Similar to other age groups, children often present with hemiplegia. However, unlike in adults, the hemiplegia usually resolves within a week with only minor motor deficits dependent on the severity of the stroke . Sensory or cognitive abnormalities tend to be unusual in children unless the infarctions are bilateral . The full neurological deficits may only emerge as the child develops, but can impact their life permanently. Of children who survive a stroke, about 60% will have permanent neurological deficits .