In the early stage of SE, seizures can be easily controlled by drugs that reduce excitement or enhance inhibition. However, the effectiveness of gamma aminobutyric acid (GABA)-ergic drugs such as BZD decreases over time [14–16], because repetitive seizures reduce the number of functional GABA receptors through the inactivation process that converts GABA receptors into vesicles and transfers them to lysosomes or the Golgi apparatus [16, 17]. Therefore, rapid administration of RMeds is an essential part of SE management . SE is considered to pose a potential threat to the human brain, leading to damage, when it occurs for over 30 min [6,8,11–13,19,20]. In our study, we examined patients who had motor seizures lasting for 30 min accompanied by potential brain damage, and they were considered to show poor response to GABAergic drugs. We determined whether the prognosis of these patients was different after arriving at the emergency room according to the clinical characteristics that cause long-term seizures and the administration time of RMed.
More than three doses of RMed were required to control convulsive SE in 71.4% of acute symptomatic cases. On the other hand, in 42.9% and 36.4% of idiopathic and chronic symptomatic convulsive SE cases, respectively, more than three doses were required. It is thought that detailed medical history-taking in the pED can provide clinicians with important data for predicting the prognosis of SE. Additionally, if multiple medications are required to stop seizures, then, brain imaging and cerebrospinal fluid testing should focus on identifying diseases such as encephalitis, which can be affected by cognitive dysfunction and life-threatening conditions if proper treatment is not provided.
If SE with motor seizures persists for > 30 min, then, homeostatic failure may set in and instability of vital signs may occur [11–13]. Therefore, if the duration of motor seizures is not precise, according to the physician’s judgement, endotracheal intubation can be performed before other treatments such as immediate administration of first-line RMed. In this study, only three patients required endotracheal intubation, and two patients required the use of inotropes owing to hypotension. When RMed administration was > 5 min, a trend of requiring ICU treatment was observed, which was statistically significant. Thus, the rapid control of seizures is considered important, and we emphasize on educating caregivers regarding the impact of seizure duration on prognosis and consider approving the administration of prehospital drugs (e.g., DZP rectal gel) in prehospital emergency medical services. It is necessary to establish a system that allows quick transfer of patients to the pED on arrival.
This study had some limitations. For example, this study was performed with a small number of enrolled patients recruited from a single institution. Primary data collection was performed retrospectively, which could be inaccurate. Moreover, there could be selection bias.
In the future, based on the research finding that the number of functional N-methyl-D-aspartate receptors and the number of functional GABA receptors at synapses may change as SE progresses [16, 17], further studies are needed regarding first- and second-line RMeds used in pEDs. Further research on the prevention of brain damage caused by persistent SE and the postictal phase management should also be conducted.