SUDEP and the Burden of Sudden Death in the Young

More than 4,000 people in the United States below the age of 35 die suddenly each year without an apparent cause of death on routine autopsy. While we in the epilepsy community typically think of this in the context of sudden unexpected death in epilepsy (SUDEP), a majority of sudden unexpected deaths in young people occur without a known history of seizures or epilepsy.

• Sudden death may occur for many reasons and is a topic of intense investigation because it is a significant cause of premature death for young people. Pediatricians often encounter sudden death in infants (<1 year) where it is termed sudden infant death syndrome (SIDS) or in toddlers, termed sudden unexpected death in childhood (SUDC).

• It is also an area of active research for cardiologists because some of the individuals who die harbor subtle structural or genetic abnormalities in the heart that predispose them to fatal arrhythmias.

• Seizure disorders and SUDEP contribute to some of these unexpected deaths. Several recent studies have examined the rates of seizures and epilepsy in people that have died suddenly.

  • In a large retrospective study of sudden unexpected death cases between 2000 and 2006 in Denmark, 30% of those deaths were determined to be due to probable/definite SUDEP.

  • Epilepsy-related sudden death was less common in young children than in those greater than 18 years of age.

  • The authors calculated that having epilepsy increased the risk of sudden death 14-fold in young people between one and 35 years of age, even when adjusted for coexisting medical conditions that may occur with epilepsy.

  • Seizures may contribute to unexpected death in other groups. In a series of cases, 50% of the deaths had either a history of or suspected febrile seizures.

Because epilepsy is such strong risk factor for sudden death, the scientific community studying sudden death is very interested in understanding better how it contributes to untimely deaths and whether there are common mechanisms at play.

• Recently, a collaboration among multiple federal agencies – the Centers for Disease Control and Prevention (CDC); the National Lung, Blood and Heart Institute (NLBHI); and the National Institute for Neurologic Disorders and Stroke (NINDS) – has been announced to perform widespread surveillance through public health and medical examiner/coroner offices and to create a standardized approach to studying all sudden death in young people less than 24 years old.

• The study, which is set to start this year, will be an expansion of the sudden unexpected infant death registry that has been tracking deaths in infants less than one year old. Such large-scale systematic assessments may uncover new risk factors, reveal the various mechanisms involved and lead the way to interventions; the successful back to sleep campaign to reduce the risk of SIDS grew out of similar, large-scale systematic studies in the 1980s and 90s.