In Children, Elevated Intracranial Pressure Found to Be a Risk Factor for Epilepsy
ARTICLE IN BRIEF
In a prospective analysis, investigators reported that seizures occurred in 18 percent of children in the first year after an intracerebral hemorrhage and in one-third of the children after two years.
When an artery ruptures in the brain of a child, the resulting hemorrhage increases the risk of seizures both immediately and in subsequent years, but by how much?
A prospective study that followed 73 such children — 20 neonates up to 28 days of age and 53 children from 29 days of age up to 18 years of age — has found that seizures occurred in 18 percent of children in the first year after an intracerebral hemorrhage and in one-third of the children after two years. Epilepsy developed in about 4 percent of the children after one year, and up to 13 percent after two years.
The study also showed that nearly 30 percent of the 46 children who were monitored with continuous EEG showed evidence of electrographic-only seizures that produced no visible symptoms.
“A clinician wouldn't know that seizures were occurring without EEG leads on a child's head,” said lead author Lauren A. Beslow, MD, a child neurologist in the departments of pediatrics and neurology at the Yale University School of Medicine. “Monitoring should be considered in this population since we now know subclinical seizures are quite prevalent.”
According to Dr. Beslow, the overarching goal of the study, published online Feb. 7 in JAMA Neurology, was to increase the ability of neurologists to predict the risk of seizures after an infant or older child has an intracerebral hemorrhage — intraparenchymal and/or intraventricular hemorrhage not caused by trauma, brain tumor, hemorrhagic transformation of arterial ischemic stroke, or cerebral sinus venous thrombosis — which would help to improve medical management.
A 2009 paper in Stroke led by this study's senior author, Lori C. Jordan, MD, PhD, of the Johns Hopkins University School of Medicine, had determined that the volume of intracerebral hemorrhage in children predicts outcome, with hemorrhage volume greater than 4 percent of total brain volume producing severe deficit or death. Seizure outcome, however, had not been well studied, so Drs. Beslow and Jordan organized the current prospective study to determine how likely children would be to have recurrent seizures or epilepsy following intracerebral hemorrhage.
“That's a question parents often ask — will my child have seizures?” Dr. Beslow said. “We needed a little more information to be able to answer that question.”
Previous retrospective studies estimated that anywhere from 10-25 percent of children would have seizures following an intracerebral hemorrhage, but failed to provide data about what to expect at one year, two years, and so on. “Here we used a prospective cohort and a time-to-event analysis so we could home in much better on what the risk of seizures and epilepsy really is,” Dr. Beslow said. “Now we need to follow this cohort because we anticipate the risk will increase in subsequent years.”
The researchers determined that the risk of later seizures and epilepsy (defined as two or more remote symptomatic seizures) was increased in those with elevated intracranial pressure that required surgical or medical intervention. Also, those who had an intracerebral hemorrhage during the neonatal period appeared to be at lower risk of seizures and epilepsy than older children.
“We were surprised by this,” Dr. Beslow said. “We expected neonates would have higher risk of later seizures.”
Dr. Beslow and her colleagues plan to increase the size of their cohort and follow it as long as possible to observe quality of life and risk for seizures at 5 and 10 years after the hemorrhage.
EXPERTS WEIGH IN
An editorial in the same issue of JAMA Neurology predicted that the data will help physicians counsel parents and families about the risks of intracranial cerebral hemorrhage in children.
“One of the things that you're always trying to decide is the ongoing seizure risk and the risk of epilepsy,” said E. Steve Roach, MD, a professor of pediatrics and neurology at Ohio State University College of Medicine in Columbus, who co-authored the editorial with Geoffrey L. Heyer, MD, a colleague at Nationwide Children's, where Dr. Roach is chief of pediatric neurology and vice chair of pediatrics.
“The tradition is, if someone comes in and has a seizure, we keep that individual on antiseizure medication for six to eight months and then stop,” said Dr. Roach, who is also the current president of the Child Neurology Society. “That may seem intuitive, but there are no good data backing it up.”
This puts physicians in a delicate position, according to Dr. Roach. If a physician sends a child home without antiseizure medication and the child has a seizure, the physician could be accused of violating the standard of care. With data showing that only about 13 percent of children who have an intracranial hemorrhage develop epilepsy, a physician could claim justification for not putting the child on long-term antiseizure medication.
“Thirteen percent is not a trivial risk, but medications have issues too,” said Dr. Roach. “There may be residual issues involving the child's strength, stamina, behavior, and so on, and long-term anti-seizure medication could make those problems even more troublesome. I can see how reasonable people might still prescribe such medication, but this study at least provides evidence that allows us to tell the family, 'The acute illness seems to have passed, and here's what we know about ongoing risk.' I suspect a lot of the time parents would decide not to go with long-term antiseizure medication.”
The data may also encourage physicians to tell parents that after intracerebral hemorrhage children face a risk of seizure and epilepsy, said Christine Fox, MD, assistant professor of neurology at the University of California San Francisco School of Medicine.
“If you don't think a seizure is going to be likely, you may not talk to families about the possibility,” said Dr. Fox, a pediatric neurologist who also has done research on pediatric stroke. “It's important for parents and families to know that seizures are a possibility down the line. If you counsel them and tell there is a potential for seizure, it might be less scary if it happens. It also gives you a chance to talk about what to do if a seizure happens. Sometimes that little bit of information ahead of time can be very helpful for parents.”
The finding that subclinical seizures detectible only through EEG are occurring in some of these children provides another valuable insight for clinicians, according to Dr. Fox.
“There have been papers that show we miss more electrographic-only seizures than we'd like,” said Dr. Fox. “They probably have clinical significance, and I think it's important to consider EEG monitoring in the acute period, not just for intracerebral hemorrhage, but for other neurologic problems too.”
Dr. Fox is also eager to see the results of follow-up studies of the children in this cohort, which she expects will provide invaluable information about long-term seizure risk.