Peri-ictal Brainstem-Driven Posturing and Its Meaning

Sudden unexpected death in epilepsy (SUDEP) accounts for an estimated 5.2% of all epilepsy-related deaths, and the risk for patients 21 to 40 years of age is almost 24 times that in general population.¹ Patients with severe treatment-resistant epilepsy face an exponentially increased risk with an incidence at 1 in 100 person-years.² The presence and annual burden of generalized convulsive seizures (GCS) in the year preceding death are the biggest risk factors, posing a 27-fold increased risk.³ The Mortality in Epilepsy Monitoring Unit Study (MORTEMUS), an international retrospective review of witnessed SUDEP in epilepsy monitoring units, demonstrated that SUDEP occurred in a close proximity to GCS after which a transient cardiorespiratory dysfunction progressed to terminal apnea and cardiac arrest.⁴ Respiratory monitoring of patients admitted to epilepsy monitoring units identified a postictal central apnea (PCCA) in 31.2% of GCS, and a prolonged postictal generalized EEG suppression (PGES) especially seemed to facilitate PCCA.⁵ In addition, PCCA co-occurred with asystole at an incidence rate of 10.2 per 1,000 patient-years. PGES has been variably associated with SUDEP and linked to the presence and duration of the tonic phase of GCS and to a delayed administration of supplemental oxygen.⁶ Because not all convulsive seizures lead to PCCA, PGES, or SUDEP, there is a need for bedside biomarkers of PGES, dangerous respiratory dysfunction, and ultimately SUDEP risk.