Seizures with autonomic symptoms and sudden unexpected death in epilepsy (SUDEP)

Abstract

The autonomic nervous system, formerly the vegetative nervous system, is a division of the peripheral nervous system that supplies smooth muscle and glands, and thus influences the function of internal organs. The hypothalamus is the main center responsible for the autonomic functions in the central nervous system. Other anatomical structures can be listed as cingulate gyrus, amygdala, paraventricular nucleus. The central autonomic network involved in the pathophysiology of autonomous epilepsy is represented in the non-dominant hemisphere. Autonomic seizures are shown in temporal and insular lobe epilepsies commonly. Blood pressure changes, heart rhythm disturbances (tachycardia, bradycardia, arrhythmia, asystole), respiratory changes (apnea, hypopnea, bradypnea), salivation increase, vomiting/retching, pilo-erection, sweating increase, mydriasis/miosis, spitting, water drinking, genital automatism, intestinal motility disorders are clinical signs in autonomic epilepsy. SUDEP (sudden unexpected death in epilepsy) is defined as sudden, unexpected, nontraumatic, non-drowning death in an individual with epilepsy, witnessed or unwitnessed, in which post-mortem examination does not reveal an anatomical or toxicological cause of death. The vast majority of SUDEPs occur in the aftermath of a generalised tonic-clonic seizure. It’s responsible for 17% of deaths in epileptic patients. Witnessed recorded SUDEP cases involve postictal cardiorespiratory dysfunction with failure of arousal. It is reported that the threshold value of SpO2 is 80-86% for the risk of sudden death. While patients who have had seizures remotely and have had successful epilepsy surgeries also carry the SUDEP risk, the most important risk factor is a history of generalised tonic-clonic seizures.