Sudden unexpected death in patients with epilepsy - Definition, epidemiology and therapeutic implications

Individuals with epilepsy have a mortality rate 2 to 3 times that of the ge neral population, attributable both to any underlying disease that may be c ausing epilepsy and to the epilepsy itself. The commonest category of seizu re-related death is sudden unexpected death in epilepsy (SUDEP). The epidemiology of SUDEP has been extensively studied and a number of such studies have taken anticonvulsant drug usage as an indicator of epilepsy, although obviously this may lead to inaccuracies. Epidemiological work has also yielded information about possible risk factors for SUDEP. At present there is no evidence that any particular anticonvulsant influences this ris k, although there are anecdotal reports of sinus arrest and arrhythmias occ urring in individuals receiving carbamazepine. A recent case-control study found that the risk of SUDEP increased with increasing number of concomitan t anticonvulsants. In many cases of SUDEP, subtherapeutic anticonvulsant co ncentrations have been found at postmortem which may reflect noncompliance with medication, although the relationship between ante- and postmortem dru g concentrations is unclear. The mechanism of SUDEP is unknown, although a possible role fur anticonvuls ants in its aetiology must be considered. Some anticonvulsants, by blocking sodium channels, have a direct effect on cardiac conduction, but studies e xamining the association between anticonvulsants and cardiac arrhythmia are lacking. As there is evidence to suggest an association between seizures and sudden death, the judicious use of anticonvulsants in optimising seizure control m ay be important in the prevention of these deaths.