Mention strokes to most people — even doctors — and they envision an elderly person with a history of atherosclerosis, atrial fibrillation or hypertension. The reality is that strokes can also strike before you've taken your first breath, before you've taken your first step, before you learn to ride a bike, before you get your first pimple or before you get your driver's license.
In fact, according to research presented at the International Stroke Conference in Los Angeles in February, stroke hospitalizations are increasing among children and younger adults. Although the study doesn't explore reasons for the trend, many health experts believe that rising rates of childhood obesity, which can lead to risk factors including heart disease and diabetes, are to blame.
“Recent research reinforces how important it is to diagnose stroke in children as quickly as possible so that medical caregivers can provide emergency treatment and take measures to prevent recurrence,” says Rebecca Ichord, M.D., director of the pediatric stroke program at Children's Hospital of Philadelphia. ”We need improved awareness of pediatric stroke among primary health care providers, and more research on the best ways to prevent a recurrence after a child suffers a first stroke.”
Here is some of the critical information that Ichord and other pediatric stroke experts are hoping to disseminate to both parents and primary care providers:
Incidence: Based on their research, Ichord and her colleagues at Children's Hospital of Philadelphia estimate that as many as 12 children in 100,000 will have a stroke, which comes to roughly 9,000 cases a year. Among newborns, the incidence is 25 per 100,000 — a rate that approaches that of elderly adults. Among infants less than a year old, stroke is the sixth leading cause of death.
Risk Factors: “Risk factors for stroke in children are very different than those in adults,” says pediatric neurologist Gabrielle deVeber, M.D., director of the children's stroke program at the Hospital for Sick Children in Toronto, Canada. These include:
▪ Abnormalities of the arteries in the brain;
▪ Chickenpox and other infections;
▪ Trauma to the head and neck;
▪ Anemia caused by a diet that is deficient in iron;
▪ Sickle cell disease;
▪ Certain types of congenital heart disease, such as valve abnormalities;
▪ Autoimmune disorders, such as lupus or type 1 diabetes;
▪ Problems with blood clotting; and
▪ Excessive consumption of energy drinks containing high levels of caffeine.
Symptoms: “We divide pediatric strokes into two separate categories — neonatal and childhood strokes,” explains Heather J. Fullerton, M.D., director of the University of California, San Francisco Children's Hospital's Pediatric Stroke and Cerebrovascular Disease Center. Fullerton says that signs of neonatal stroke (birth to 28 days of life) can include:
▪ Extreme sleepiness (most healthy infants sleep for 16–18 hours per 24-hour period but wake every 2-3 hours for a feeding, followed by an hour or two of wakefulness);
▪ A tendency to only use one side of their body; and
▪ Inability to feed.
“In older children, the symptoms of a stroke are similar to what we see in adults.” She says these symptoms can include sudden onset weakness on one side of the body and complaining of the worst headache they have ever had. Here's an easy-to-remember list of stroke symptoms parents need to be on the lookout for:
▪ Sudden numbness or weakness of the face, arm or leg, especially on one side of the body;
▪ Sudden confusion, trouble speaking or understanding;
▪ Sudden trouble seeing in one or both eyes;
▪ Sudden trouble walking, dizziness, loss of balance or coordination; and
▪ Sudden, severe headache with no known cause.
Diagnosis: It takes 48 to 72 hours for parents to take children to the ER after onset of stroke symptoms. This delay is mostly due to the widespread belief that strokes don't happen to children. Even at the hospital, stroke is not the first condition that doctors look for because pediatric stroke is still fairly rare. Stroke symptoms in children are frequently attributed to other, more common problems, such as migraine, seizures or encephalitis. “Although parents typically bring their children into the emergency room relatively quickly, the median time to diagnosis is 12 hours after arrival, with more than half of all diagnoses delayed for more than 24 hours,” deVeber says. “We have now moved to a protocol in our hospital of first-test MRI rather than a CT scan, since CT imaging has limited sensitivity in detecting acute ischemic stroke in children.”
Ichord and her colleagues modified the National Institute of Health Stroke Scale (NIHSS) that is used to assess acute stroke in adults so that it can be used to diagnose pediatric stroke. The stroke scale measures the degree of impairment caused by a stroke, ranging from minor to severe, and helps doctors determine whether a stroke patient should be treated with a clot busting drug. In research studies, the NIHSS also provides an objective comparison of the effectiveness of stroke treatments and rehabilitation interventions.
“We believe [modifying the stroke scale for children] is an important first step in developing a valid pediatric acute stroke scale and is of fundamental importance for planning and executing future clinical trials in childhood stroke,” Ichord explains.
Prognosis: Recent research suggests that hemorrhagic stroke, which occurs when a blood vessel busts inside the brain, is more common in boys, while ischemic stroke, which occurs as a result of a blood clot blocking a vessel supplying blood to the brain, strikes girls more often.
“A child's prognosis typically depends on the cause and location of the stroke and the child's age,” says Fullerton, For instance, babies who have uncontrolled high blood pressure — which can occur with congenital kidney or heart disease, thyroid problems or prenatal exposure to cocaine — are at higher risk of a second stroke.
“The recurrence rate for all childhood stroke victims can be as high as 20 percent in the first two years,” she adds.
The risk of recurrence is very low for children who fall into the “unexplained stroke” category according to Fullerton.
“Babies typically have good outcomes, although they may need to undergo some form of physical and/or occupational therapy to help them overcome motor deficits. Older children may also have problems with motor strength, and we also worry more about the possibility of them having a recurrent stroke. That's why it's important for children who have had a stroke to be evaluated to determine their risk of recurrence.”
One study showed that pediatric stroke survivors had good educational and mobility outcomes, but communication, activities of daily living and socialization fell into the low-moderate range.
Treatment: There is a dearth of research on the safety and effectiveness of treatments for stroke in children. “We have aspirin, we have blood thinners, and some doctors are treating children with tPA [tissue plasminogen activator],” says deVeber. “There is a wide variability on how children are treated, depending on the center.” Though FDA approved for acute ischemic stroke in adults, tPA has not been approved for children.
If tPA is given, it's typically administered in small doses right at the clot.
In adults, tPA and other clot busters have proved effective in reducing damage to the brain in ischemic stroke if given within the first four hours after symptoms begin. But pinpointing when symptoms begin, especially in children, is problematic. In August, a nationwide study will kick off to determine whether the same four-hour window for treatment also applies to children, as well as the optimal dosage of medication.
As to the future of pediatric stroke treatment, deVeber is encouraged by increased research in the field. “Pediatric stroke [is] an important, emerging subspecialty within pediatric neurology,” she says. “Many of the clinical trials that are just starting are going to help us to better understand and treat childhood stroke.”
© 2011 American Heart Association, Inc.