Pharmacotherapy for Nonconvulsive Status Epilepticus

Nonconvulsive status epilepticus (NCSE, which includes electrographic SE) is defined as ۱۰ or more continuous minutes of nonconvulsive seizure activity; or nonconvulsive seizures adding up to >=۲۰% of any hour of recording (ACNS terminology, ۲۰۲۱). Nonconvulsive seizures/NCSE are common, especially in patients with coma or prior seizures. The chances of neurological decline and other adverse long term outcomes increase at higher seizure burdens, as has been shown in all ages and in many different clinical scenarios. There are no prospective randomized trials on treatment of NCSE, so most treatment is extrapolated from literature on convulsive SE. Thus, IV levetiracetam, valproate and fosphenytoin are first line medications. There is one class I prospective randomized trial on treatment of refractory nonconvulsive seizures (not SE): the TRENdS trial, which showed that lacosamide was non-inferior to fosphenytoin; it was actually non-significantly more effective with equal tolerability. In addition to those options, IV brivaracetam is a reasonable option, and add-on enteral medications can be helpful. General principles are that diagnosis should be as early as possible (consider use of rapid EEG devices/caps); dosing can start lower than in convulsive SE, but with close follow-up and additional doses as needed; seizure burden matters; and stop medications if there was no hint of efficacy with a full load. Other than after convulsive seizures/CSE, we try to avoid using coma-inducing medication for nonconvulsive seizures/NCSE, though it is sometimes necessary. The Yale protocol will be presented as well.