Sudden unexpected death in epilepsy (SUDEP) is one of the most frequent causes of sudden non-accidental death in young adults. The origin of SUDEP remains unknown, since it generally occurs at night, unwitnessed. SUDEP sometimes occurs in hospital, while the vital functions are being monitored and recorded. These are the data that Prof. Philippe Ryvlin, who leads the Inserm team TIGER (Translational and Integrative Group in Epilepsy Research), at the Lyon Neuroscience Research Center, has analysed in order to better understand this problem.

The international study MORTEMUS, the results of which are published in the 4 September issue of The Lancet Neurology journal, has enabled the identification and evaluation of those rare cases of cardiorespiratory arrest that have occurred in hospital units specialising in epilepsy. In total, 16 SUDEP cases were analysed, with the help of data collected from 147 units located in Europe, Israel, Australia and New Zealand, between January 2008 and December 2009. The majority of SUDEP cases studied happened at night (14 out of 16).

Results show that patients who died from SUDEP showed the same series of events leading to cardiovascular arrest. Breathing became more rapid (18-50 breaths per minute), following a severe seizure, and this accelerated breathing was followed within 3 minutes by sudden transient or terminal cardiorespiratory collapse. Where the dysfunction was transitory, the researchers observed that it recurred after several minutes, leading to terminal apnoea and subsequent cardiac arrest.

This study also highlights the suboptimal monitoring of patients admitted to specialist epilepsy units, and indicates the need for improved safety measures in these units.

“Our data help to lift the veil on the cause of these deaths, and contribute elements to help prevent these sudden deaths, for example by improving the monitoring of patients in specialist hospital units, especially at night-time,” 

explains Prof. Philippe Ryvlin, leader of the Inserm team.