It has long been difficult for health professionals to come up with a common definition and method of classifying SUDEP deaths.
In 1993, the United States Food and Drug Administration (U.S. FDA), in conjunction with Burroughs-Wellcome (pharmaceutical company), came up with a definition to define and classify Sudden Unexpected Death in Epilepsy (SUDEP) in relation to clinical studies/trials carried out by pharmaceutical companies.
SUDEP was concluded as the cause of death if:
- the victim suffered from epilepsy, defined as recurrent unprovoked seizures
- the victim died unexpectedly while in a reasonable state of health
- death occurred “suddenly” (in minutes) when known
- death occurred during normal activities (e.g. in bed, at home, at work) and benign circumstances
- an obvious medical cause of death was not found
- death was not the direct result of a seizure or status epilepticus
SUDEP cases are defined on a scale:
- Definite SUDEP: all the criteria for SUDEP was met and was confirmed by a post-mortem report
- Probable SUDEP: the criteria for SUDEP was met, however there was no post-mortem report
- Possible SUDEP: the event of SUDEP was not ruled out, however there may be other causes of death; the criteria were not sufficiently met and no post-mortem report was available.
- Not SUDEP: there were other causes of death
Researchers in the United Kingdom (Nashef et. al) proposed the following definition:
“A sudden unexpected, non-traumatic and non-drowning death in an individual with epilepsy with or without evidence for a seizure and excluding documented status epilepticus where post-mortem examination does not reveal a toxicologic or anatomic cause for death.”
For statistical and prevention purposes, it is essential to have a common definition of an illness. However, this can be extremely difficult with SUDEP. This may introduce frustration and confusion for both medical examiners and those close to the patient.
For the above reasons, the exact statistics indicating SUDEP cases are not easy to obtain. This is nobody’s fault.
SUDEP is now starting to become widely recognized as an important cause of death in epilepsy. It has been estimated that it may be even as high as 2-3 times the mortality rate of the general population. Some family doctors may not even know that SUDEP can occur. In addition, autopsy reports may indicate suffocation for many SUDEP cases because the patients are found laying face down. Status epilepticus may also be reported simply on the fact the patient was epileptic and there is no other apparent cause for death.
The result: SUDEP occurrences may be much higher than previously believed/recorded.
A rough estimate for the U.S. indicates SUDEP may play a role in 7-17% of all epilepsy-related deaths (note the huge percentage margin). Estimates will vary from country to country and will also depend on how SUDEP is defined by the coroners. Studies show that the incidence of SUDEP in young children appears to be very low.