Although they may not appear as physically injurious as convulsive seizures, nonconvulsive seizures can significantly impact the neurological outcomes and overall prognosis of patients in critical care settings. Especially in the case of status epilepticus, delayed treatment can lead to a phenomenon known as pharmacoresistance, in which the effectiveness of anti-seizure medications diminishes over time due to neurobiological changes that alter drug targets (e.g., reduced surface expression of postsynaptic GABAA receptors) and drug transport mechanisms (e.g., increased expression of drug efflux transporters) to enable self-sustaining ictal rhythms.^5,6 This underscores the importance of being vigilant and integrating clinical findings with advanced diagnostic tools like EEG to improve diagnostic accuracy for seizures and refine the management of critically ill patients to ensure comprehensive neurological care.⁷

Several studies have demonstrated the importance of EEG monitoring in the management of seizures.^8–11 Although continuous EEG monitoring would be the gold standard for diagnosing and managing nonconvulsive seizures, it is either unavailable or delayed at many centers, and it is rarely performed in the ED. This is because conventional EEG requires a large machine, a qualified technologist, and a significant amount of time for setup, and the output data must be reviewed and interpreted by a neurologist. Some institutions have the capability to perform real-time EEG monitoring and interpretation by a neurologist in the ED. Other devices have demonstrated potential use as an alternative to traditional EEG monitoring. For example, other modes of EEG monitoring may be used in the operative setting, including bispectral index monitoring (BIS) and SEDline device, to monitor depth of sedation.¹² A point-of-care (POC) EEG system has been developed to provide real-time EEG data.¹³ Preliminary data suggest that among 157 adult patients, POC EEG enabled acquisition of EEG data within 90 minutes of ED arrival, identified epileptiform activity in 36 percent of patients, and impacted treatment decisions.¹⁴ Future research is needed to determine the sensitivity and specificity of this device, particularly in the ED environment, where patients may have taken medications or recreational drugs, or may have received sedative or antiepileptic medications.

Diagnostic studies useful in determining the etiology may include POC glucose, serum electrolytes, and complete blood count. Other considerations dependent on the clinical setting and history may include CT scan, MRI, or lumbar puncture.

Management of status epilepticus includes stabilization of airway, breathing, and circulation. If a patient is obtunded or unable to protect the airway, endotracheal intubation is indicated. Following stabilization, pharmacologic therapy should be initiated with first-line therapy of a benzodiazepine, such as lorazepam. Appropriate dosing is associated with seizure termination and reduced complications.^15-17 Anti-epileptic medication may be administered concurrently, such as fosphenytoin, phenytoin, levetiracetam, or valproic acid.^18–21 Refractory status epilepticus may be treated with a continuous infusion of an antiepileptic medication, such as propofol, ketamine, midazolam, or pentobarbital.