Prolactin levels in sudden unexpected death in epilepsy

To assess serum prolactin levels in sudden unexpected death in epilepsy (SUDEP) and control groups to test the hypothesis that if seizures occur routinely as a terminal event in SUDEP, then raised prolactin levels may be an indicator of terminal seizure.

Blood was taken for measurement of prolactin levels from subjects with SUDEP and three control groups. The control groups were those with epilepsy dying from causes other than epilepsy (e.g., ischemic heart disease or injuries), physiologically stressed individuals without epilepsy (they were admitted to the hospital after an acute illness and died after several hours to 3 days), and nonepileptic rapid deaths (these people collapsed suddenly and died at the scene). In the SUDEP group, evidence for terminal seizure was considered to be at least one of the following: body found half on, half off the bed, or urinary incontinence at the scene, or bitten lips or tongue at autopsy.

There was evidence for terminal seizure at the scene or at autopsy in four of the 10 SUDEP cases. Serum prolactin levels were not significantly increased in the SUDEP group compared with the controls. None of the SUDEP subjects, including those with clinical evidence of a terminal seizure, had high prolactin levels characteristic of those observed after seizures in living subjects.

Prolactin levels are not raised in SUDEP, even if there is evidence of terminal seizure. As prolactin takes 15-20 min to peak after a seizure in life, there may be insufficient time for a prolactin increase to occur in SUDEP. Thus prolactin levels cannot be used to determine if a deceased individual with epilepsy had a seizure or to answer the broad question whether SUDEP is always associated with a terminal seizure.