Sudden unexpected death in epilepsy is rare and thought to mainly affect people with hard-to-treat seizures, but a new study suggests that even people with well-controlled epilepsy may be at risk.
That was especially true if someone had missed their last dose of medication or was sleep-deprived, the researchers found. Drinking too much alcohol was also implicated in some of the sudden unexpected death in epilepsy (SUDEP) cases they studied.
"If you have high blood pressure or high cholesterol, you can probably get away with taking your medicine only 80% or 90% of the time. But if you have epilepsy and you miss one dose, it can be deadly if the right stressor or hormonal factors are present," explained the study's senior author, Dr. Orrin Devinsky. He's director of the Comprehensive Epilepsy Center at NYU Langone Health in New York City.
Devinsky said the researchers don't want to scare people with epilepsy and their loved ones. He said sudden unexpected death in epilepsy is, indeed, rare.
"For the average person with epilepsy, there's about a 1% chance of dying from SUDEP over a year," he said.
But SUDEP can occur in anyone with epilepsy, and Devinsky wants people to be aware of the risk and take steps -- such as making sure to take epilepsy medications as directed -- to lessen the chances of sudden death.
Many people are unaware that sudden death is a risk in epilepsy. In fact, the current study found that only 16% of close family members of people who died from SUDEP had been told that it was a possibility.
Devinsky said that these are uncomfortable conversations to have, and that many neurologists will only bring up SUDEP if someone has missed taking their medications. But he said it's similar to a cardiologist warning you that you have a risk of heart attack if you have conditions like high blood pressure and high cholesterol.
Previous studies found that people who had recently had a seizure or those who had difficult seizures were more likely to die suddenly. It was also thought that people who had generalized tonic-clonic seizures were more likely to have SUDEP. These are whole-body seizures that cause convulsions and a loss of consciousness.
The current study looked at cases referred to the North American SUDEP Registry, which was set up in 2011. There were 237 cases of probable or definite SUDEP. The researchers looked deeper into these cases, collecting information from family members and medical records.
Deaths occurred at any age, ranging from one to 70 years old. The average age of death was 26, the study found.
Fifteen percent of those who died had been seizure-free for a year before their death. Four percent had never had a tonic-clonic seizure, the findings showed. About one-third of people who died had fewer than 10 generalized tonic-clonic seizures in their lifetime.
In most cases -- 93% -- SUDEP occurred when the person was alone. Seventy percent of the deaths happened during sleep.
Just 37% had taken their last prescribed dose of epilepsy medication. Their next of kin said about one-third sometimes forgot medication, skipped doses, stopped taking their medication, or took less of a drug to reduce side effects.
Devinsky said the reason for these deaths still isn't clear. He said that after a seizure, the brain may be in the "off" position for a short time, and that the usual warning systems might not be functioning properly. So, if a seizure leaves someone in a face down position and unable to breathe, their brain may not send the typical arousal signals to move and make breathing possible again.
Findings from the study were published online June 19 in Neurology.
Dr. Jorge Burneo wrote an editorial accompanying the study. He said a key message from the study is that SUDEP doesn't only affect people with difficult-to-treat epilepsy.
"Those who are fairly well-controlled can die from a seizure. Epilepsy doesn't need to be bad for you to be at risk of SUDEP," Burneo said. He's a professor of neurology, biostatistics and epidemiology at Western University in London, Canada.
He said families need to be aware that SUDEP is a possibility and people with epilepsy need to be "very faithful about taking their medications."
Devinsky said people with epilepsy should create a system for taking their medication. "Create routines around taking your medication. Don't brush your teeth or get into bed before taking your medication," he suggested. Be especially vigilant in times of stress and when your routine changes, he added.
Both experts said to talk to your doctor if you're having trouble taking your medication because of side effects or for financial reasons. There are a number of drugs available to treat epilepsy, so there are usually options available.
Learn more about SUDEP from the Epilepsy Foundation.