The results of this study are published in the journal of Epilepsia.
Researchers surveyed 819 people who were part of a community-based registry in Tasmania. They were asked about seizure-related injuries over their lifetime and during the previous 12 months.
‘People who had seizures were found to be 15 to 19 times higher risk of drowning.’
Of those surveyed, 43.1% had a lifetime history of at least one injury, and 9.9% had an injury in the previous 12 months.
Many studies of seizure-related injuries are hospital-based and can show high injury rates, noted Ley Sander, professor of neurology at University College London and head of the Department of Experimental and Clinical Epilepsy, who was not involved in the study. “People see those studies and say ‘Oh, those injuries don’t happen in real life.’ This study shows that they do and that having active epilepsy is a risk factor for injury.”
“We know that morbidity from seizure-related injuries is common, but to my knowledge, there have been very few studies trying to map this,” said Sander. “This study is quite robust because of the methodology.”
Seizure frequency was correlated with the risk of injury. That might not seem surprising, but it’s a key finding, said senior study author Wendyl D’Souza, an epileptologist at St. Vincent’s Hospital, Melbourne and associate professor at University of Melbourne Medical School.
“We found that having even just one seizure a year is a risk for injury,” he said. “I think that reflects the unpredictability of seizures. If you have frequent seizures, you often restrict your activities, and you’re mindful of getting in the pool or playing sports. But if seizures happen only once a year, you’ve maybe lulled yourself into thinking that you’re okay.”
AgreeSander, “This study shows that you need to be seizure free to be safe. A 50% reduction in seizure frequency might be good as a regulatory outcome, but it’s not good for patients.”
After adjusting for seizure frequency, three risk factors remained:
- Impaired awareness during seizures
- Convulsive cluster seizures
- Having seizures only when awake (versus during sleep)
Head injuries were common, with a lifetime incidence of 21.6% and a recent incidence of 3.9%. About 1 in 4 head injuries required stitches.
Other types of injuries included immersion in water—while bathing, showering or swimming—as well as burns, cuts, broken bones and dental injuries. Eighteen percent of the injuries were reported as occurring in public, and about 60% in the home.
“The study showed that water is a big risk,” said D’Souza. “And importantly, it reinforced that drowning risk happens at home.”
The risk of drowning in people with epilepsy is 15 to 19 times greater than that of the general population. “In the UK there are between 80 and 120 bathtub drownings every year, and the great majority of those are people with epilepsy,” Sander said. He suggests simple safety measures, such as making someone else in the house aware of where you are and keeping the bathroom door unlocked.
Eleven percent of participants reported ever having a seizure while driving; however, only 1 in 10 participants chose to answer driving-related questions. The authors statistically addressed the missing data and found that the non-responses had a minimal effect on the results.
The study did not find that people who had seizure warnings (sometimes called auras) were at lower risk of injury.
“Patients think if they have a warning of a seizure, they’ll be okay,” said D’Souza. “But if you have a warning, that usually means you’re having a lot of seizures, and not all of them come with a warning, and patients don’t know they’re having some of them. It’s sad and hard to reinforce to patients that they have seizures they don’t even know about and that it puts them at risk [for injury].”
The overall mortality rate in people with epilepsy is two to three times that of the general population. In many countries, seizure-related injuries and drownings are major contributors.