Epidemiology and pathophysiology of autonomic seizures: a systematic review

Abstract

Purpose: To review the epidemiology and pathophysiology of autonomic symptoms and signs during epileptic seizures. Methods: We performed a systematic literature search on the following autonomic symptoms and signs during epileptic seizures: cardiovascular changes, respiratory manifestations, gastrointestinal symptoms, cutaneous manifestations, sexual and genital manifestations, and urinary symptoms. Results: Autonomic symptoms and signs can represent the predominant symptom at the onset of a focal seizure, which would then lead to the seizure being classified as a focal onset autonomic seizure. Conversely, clinically relevant autonomic symptoms and signs frequently accompany seizures of focal, generalized, and/or unknown onset, but the seizure is regardless classified according to other, more relevant features. Autonomic symptoms and signs do not represent mere reactions to motor activity or other behavioral seizure manifestations, but rather they are generated by epileptic discharges affecting the central autonomic network. We have reviewed the localizing and lateralizing information currently available on the seizure onset zone and on seizure propagation pathways as provided by systematic analysis of specific autonomic seizure symptoms and signs. We present data on how autonomic seizure symptoms and signs are useful for gaining a better understanding of the anatomical and functional organization of the central autonomic network. Finally, we discuss the differential diagnosis of focal autonomic seizures with autonomic symptoms and signs representing the sole seizure manifestation versus various non-epileptic conditions. Conclusions: Autonomic seizure symptoms and signs are relevant in clinical epileptology and open a unique window on the functional organization and pathophysiology of the central autonomic network.