Sudden Unexpected Death in Epilepsy

Sudden Unexpected Death in Epilepsy (SUDEP) denotes the sudden, non-traumatic and non-drowning demise of individuals with epilepsy, in which no other cause of death is identified at postmortem. It represents the leading direct epilepsy-related cause of mortality, particularly in patients with poorly controlled seizures. Epidemiological studies estimate an incidence of 1 to 1.2 per 1 000 person-years in adult populations, rising to 3–9 per 1 000 in those with drug-resistant epilepsy. Key clinical risk factors include frequent generalised tonic–clonic seizures, nocturnal convulsions, polytherapy with antiseizure medications and suboptimal adherence. Pathophysiological mechanisms are multifactorial: central respiratory depression in the postictal phase, cardiac arrhythmias triggered by ictal autonomic dysfunction, prolonged postictal electroencephalogram suppression and genetic susceptibilities affecting cardiac and neuronal ion channels. Neuropathological investigations reveal alterations in brainstem respiratory nuclei and limbic structures, while advanced neuroimaging has identified volume changes in cerebellar, thalamic and insular regions that regulate cardiorespiratory homeostasis. Practical approaches to risk reduction include seizure control optimisation, nocturnal monitoring devices, personalised risk inventories and emerging neuromodulation therapies such as vagus nerve stimulation. A global effort to stratify risk and develop targeted interventions is essential to mitigate this largely preventable cause of death in epilepsy.

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Sudden Unexpected Death in Epilepsy publication trend

The graph below shows the total number of articles in sudden unexpected death in epilepsy across all publications each year (not limited to Nature Index journals).

Technical terms

SUDEP: Sudden Unexpected Death in Epilepsy, death in epilepsy unaccounted for by other causes at autopsy.

Ictal: Pertaining to the seizure event itself.

Postictal: The period immediately following a seizure, often marked by impaired consciousness and autonomic instability.

Central apnoea: Cessation of respiratory effort due to failure of central respiratory drive.

Generalised tonic–clonic seizure: A seizure involving widespread bilateral cortical networks, manifesting as stiffening (tonic) followed by rhythmic jerking (clonic) of muscles.

Arrhythmia: Any disturbance of the normal cardiac rhythm, which may range from benign to life-threatening.

Heart rate variability (HRV): A measure of autonomic regulation of cardiac function, reflecting the variation in time intervals between heartbeats.

References

1. Failure to breathe persists without air hunger or alarm following amygdala seizures. JCI Insight (2023).
2. Cardiac arrhythmias during or after epileptic seizures. Journal of Neurology Neurosurgery & Psychiatry (2015).
3. Risk Assessment for Sudden Death in Epilepsy: The SUDEP-7 Inventory. Frontiers in Neurology (2015).
4. The ventrolateral medulla and medullary raphe in sudden unexpected death in epilepsy. Brain (2018).
5. Incidence, Recurrence, and Risk Factors for Peri-ictal Central Apnea and Sudden Unexpected Death in Epilepsy. Frontiers in Neurology (2019).
6. Genetic Basis of Sudden Unexpected Death in Epilepsy. Frontiers in Neurology (2017).
7. Cerebellar, limbic, and midbrain volume alterations in sudden unexpected death in epilepsy. Epilepsia (2019).
8. Baseline elevation and reduction in cardiac electrical instability assessed by quantitative T-wave alternans in patients with drug-resistant epilepsy treated with vagus nerve stimulation in the AspireSR E-36 trial. Epilepsy & Behavior (2016).