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July 5, 2011 -- People with epilepsy who are otherwise healthy are known to have a risk of unexplained sudden death that is more than 20 times higher than the general population. Doctors call it sudden unexpected death in epilepsy or SUDEP.

However, that risk may be reduced by a variety of precautions, a new review of research finds.

The review, published online in The Lancet, should be understood properly by those with epilepsy, says researcher Simon Shorvon, MD, professor of neurology at University College London. "Life is full of risks," he says, ''and [it's] important to keep in perspective. "

For the review, Shorvon searched for published medical studies focusing on the seizure disorder epilepsy and sudden death from 1950 to 2010, finding 580 articles. He focused on those published in the past five years.

About 3 million Americans have epilepsy and seizures, according to the Epilepsy Foundation.

How to Reduce Risk of Sudden Death

Shorvon pooled the data from his analysis of risk factors. He found:

The more often a seizure known as tonic-clonic occurs, the higher the risk. These are a type of generalized seizure that affects the entire brain.

Men were at higher risk than women.

Those who had epilepsy long term were at higher risk than those who had it for a shorter time.

Those on many epilepsy medicines were at higher risk than those not taking many medicines.

Shorvon also found SUDEP usually occurs when people with epilepsy are not observed by others and often at night.

To reduce risk, ''reducing the number of convulsions is probably the single most important way of prevention [of SUDEP],'' Shorvon tells WebMD.

If drugs are changed, the doctor should change them in a gradual manner.

Patients at high risk should be supervised at night. A person can supervise the patient or the patient can use alarms that are set off by seizures.

Epilepsy drugs that have potential cardiac and respiratory effects should be prescribed with care.

Doctors should discuss risks of sudden death with people with epilepsy.

The measures suggested to reduce SUDEP risk are only speculative suggestions, Shorvon writes, based on data about what leads to SUDEP. If medications don't help, Shorvon writes, epilepsy surgery can help make a patient seizure-free and probably reduces the risk of SUDEP.

Shorvon also addresses the debate about how much information on the risks of SUDEP people need. He believes doctors should discuss the risks fully. "Patients have a right to know about SUDEP and for their questions to be fully addressed," Shorvon tells WebMD.

"Treatment is a partnership between patient and doctor and depends on trust being established between them," he says in an email. "Information provision is a critical element of this trust."

Shorvon reports consultant fees from Janssen Cilag, UCB Pharma, and Eisai and has received speaker's honoraria from GlaxoSmithKline, Janssen Cilag, and UCB Pharma. His co-author Torbjorn Tomson reports research grants from Eisai, GlaxoSmithKline, Janssen-Cilag Novartis, Sanofi-Aventis, Pfizer, and UCB Pharma. Tomson also received speaker's honoraria from UCB Pharma and Eisai and travel expenses from UCB Pharma.

And rightfully so, says Mehta, who reviewed the study findings for WebMD. But he also cautions patients to keep the increased risk in perspective, as it is compared to those in the general population, who have a low risk of sudden unexplained death.

Even so, he says the new review offers an important message: "I think the news for people who have epilepsy is that seizure control is important."

"The data are pretty clear, that every time you have a seizure there is a small risk of death," he says. "If we look at the data carefully, it looks like those with more severe seizures and more frequent have a higher risk."

So, he says, it's important to control the seizures, often with medication and less often with surgery. "Probably less than 1% or 2% will have surgery," he tells WebMD.

"I think it's also very important for patients to determine what kind of seizure they are having," Mehta tells WebMD, as some types appear to be related to higher death risk, research suggests.

Many doctors offer video monitoring of seizures, after taking patients off mediation temporarily, to help determine what type of seizure they are having, Mehta says.

That, in turn, will help the doctor determine the best treatment plan, he says.