Status Epilepticus a risk factor for Sudden Unexpected Death in Epilepsy (SUDEP): A scoping review and narrative synthesis

Background

Sudden Unexpected Death in Epilepsy (SUDEP) is a leading cause of mortality among people with epilepsy (PWE). Risk factors such as increased seizure frequency, drug-resistant epilepsy, and early epilepsy onset are well recognised. However, little evidence of the role of seizure severity, specifically Status Epilepticus (SE) on SUDEP risk exists.

Objective

To identify mechanisms, risk factors and clinical characteristics overlap between SE and SUDEP.

Methods

A scoping review using the PRISMA-ScR model was performed by two reviewers using suitable search terms. The PubMed Advanced Search tool along with the ancestry method was utilised to identify suitable articles published between 06/1992 and 05/2023. Quantitative, qualitative and mixed method studies were included. A narrative synthesis was undertaken and is presented as themes and subthemes.

Results

Of 5453 papers identified in the preliminary search, 50 studies were suitable for final analysis. Key themes include overlap between SE complications and SUDEP risk factors (pharmaco-resistant generalised tonic-clonic epilepsy, intellectual disability), overlap of shared risk factors (alcohol abuse, developmental epileptic encephalopathies) and clinical characteristics (cardiac and respiratory). SE’s role in development of drug-resistant epilepsy was the strongest potential mechanism for SE’s contribution to SUDEP risk. SE’s contribution to recurrent ictal hypoxaemia episodes and lowered heart rate variability suggests a relationship with SUDEP needing further study.

Conclusions

This review identifies research areas of influence of SE on SUDEP risk. Such research could inform counselling for patients concerned about seizure severity in relation to their SUDEP risk and optimise surveillance and subsequent management of post-SE epileptogenic outcomes.