Despite major advances in the field, a majority of pediatric stroke cases go undiagnosed within the first 24 hours.
TORONTO—The field of pediatric stroke is developing at a rapid pace, largely due to an increase in collaborative research as part of the International Pediatric Stroke Study (IPSS). Gabrielle deVeber, MD, Director of the Children’s Stroke Program at the Hospital for Sick Children, Toronto, and IPSS principal investigator, reported on recent insights in this emerging field at the 62nd Annual Meeting of the American Academy of Neurology. She stated that the key clinical challenges in childhood stroke include delayed diagnosis and an absence of clinical evidence to support treatment protocols.
“There is a wide variability in how a child is treated with stroke depending on the center, reflecting a lack of research to guide treatment,” Dr. deVeber told Neurology Reviews. “We need better identification of stroke, more funding for research, and clinical trials to assess new and exciting treatments.”
With more than 2,000 children at 80 sites in 35 countries, the IPSS is working to develop the needed research to continue to update and revise pediatric thromboembolism and stroke protocols. In the past two years, the IPSS has published seven manuscripts, with more in progress. Furthermore, publications in the field of pediatric strokes have grown exponentially in the past decade.
Not Little Adults
“Stroke in neonates and children is different from stroke in adults,” Dr. deVeber said. “Their coagulation, vascular, and neurologic systems are immature and therefore function differently.”
Although childhood stroke is rare compared with adult stroke, it is listed as one of the top 10 causes of death in children younger than 1. Those who survive all too often have lifelong deficits, debilitation, and a reduced quality of life.
In the immature brain, stroke has a subtle presentation, “especially in newborns who have very little hope of showing focal hemiplegia, even when damage involves the motor cortex, because that part of the brain is not yet plugged in,” Dr. deVeber explained. This is further complicated by subtle imaging findings.
Stroke presentation differs in age groups as well, with the majority of neonates presenting with seizures and the majority of older children presenting with focal neurologic deficits. “Seizure is common in both [age groups], but it is 2.5 times more common in newborns, because of the lower seizure threshold in the immature brain,” she noted.
Poststroke Recovery
The immature brain has increased plasticity compared with the adult brain; however, recovery of plasticity has both advantages and disadvantages in children. In adults, tasks may need to be relearned after a stroke, but “at least there is some laid down memory of motor tasks and speech therapies,” Dr. deVeber reported. “That is one of the challenges for a child who has not yet developed those skills.”
Long-term follow up of these children has revealed that newborns may not show deficits immediately following the stroke, but they become apparent as the children grow older. “Their immature brain doesn’t manifest the damage until they are expected to perform milestones,” she explained. “These children have emerged with the deficit gradually, not due to recurrent stroke, but due to hidden deficits that are unseen at the time of stroke.”
Immature Arteries
With smaller arteries, children are more susceptible to occlusion by emboli, compression, or traumatic injury. At the same time, children&rsqo; arteries are relatively healthy, so diffuse arteriopathies, such as atherosclerosis, are rare.
“Instead, what you have are focal arteriopathies, and this is typically unilateral, intracranial, and inflammatory,” Dr. deVeber explained.
Childhood arteriopathies can be transient or progressive. A common transient cerebral arteriopathy of childhood is post-varicella angiopathy, which occurs after chicken pox. Dr. deVeber presented a case of a 7-year-old boy who had three brief episodes of right hemiparesis, followed by abrupt persisting hemiparesis. The initial MRI showed an acute basal ganglia infarct.
“We have come to recognize that this cause of stroke that is very prominent in children is very different than strokes we see in adults,” Dr. deVeber noted. “This is really a disease of the Circle of Willis but only one-sided—for example, the middle cerebral artery.” Other childhood arteriopathies include dissection, vasculitis, moyamoya, and radiation vasculopathy.
Another issue with pediatric stroke is that children have immature clotting systems. The risks and benefits of antithrombotic treatments are different in children than in adults. Infants especially are relatively hypercoaguable and appear to form clots more easily than older children or adults.
Clinical Challenges
Delayed or missed diagnosis presents the greatest challenge in treating childhood stroke. “Interestingly, parents bring their children in relatively quickly,” said Dr. deVeber. “In our study, children were brought to the hospital within a median of 1.7 hours after onset, and the delays actually happen when they get to the hospital. Many of these were pediatric hospitals, so stroke wasn’t on the radar. Over half were diagnosed more than 24 hours after arrival, and the median was 12.7 hours.”