Status epilepticus (SE) is a life-threatening medical emergency that requires prompt recognition and treatment. SE is not a specific disease but rather a manifestation of a primary central nervous system (CNS) insult or a systemic disorder with secondary CNS effects. Adherence is mandatory to the basic principles of neuroresuscitation, the A, B, and Cs, followed by a planned treatment protocol. Proper management requires the identification and treatment of the underlying cause in order to facilitate seizure control and prevent ongoing neurologic injury. Specific clinical and electrographic stages of SE have treatment implications and there are certain special circumstances that require immediate seizure control. This chapter focuses on the evaluation and treatment convulsive SE (CSE), including refractory SE (RSE).
SE is defined as more than 30 minutes of either continuous seizure activity or two or more sequential seizures without full recovery of consciousness in-between.1 However, treatment starts before this duration. Lowenstein, Bleck, and Macdonald proposed an "operational definition" for treatment of generalized CSE in adults and older children (age >5 years): 5 minutes or more of either a continuous seizure, or two or more discrete seizures between which there is incomplete recovery of consciousness.2 These principles apply to all ages.
SE is classified by seizure type, either partial (focal) or generalized as defined by the International Classification of Epileptic Seizures.3 A modified system is based on semiology4: CSE or nonconvulsive SE (NCSE). NCSE occurs with either generalized (absence) or focal (partial complex) epilepsy, or as the end stage of CSE. SE is also classified by etiology: acute symptomatic, remote symptomatic, remote symptomatic with acute precipitant, progressive encephalopathy, cryptogenic, idiopathic, and febrile SE.5
CSE consists of continuous tonic and/or clonic motor activity, which may be asymmetric, overt, or subtle, with bilateral, although frequently asymmetrical, electroencephalogram (EEG) ictal discharges and altered consciousness4,6 NCSEs or subtle CSEs have no obvious signs despite marked impairment of consciousness and bilateral EEG discharges,6 and may evolve from convulsive SE or its apparent successful treatment. Pseudo-SE also occurs in children.7,8
STAGES OF STATUS EPILEPTICUS
The clinical stages of SE are listed in Table 38–1.9 The premonitory stage consists of confusion, myoclonus, or increasing seizure frequency; the early stage, continuous seizure activity; subtle CSE or NCSE may develop in the refractory stage. If identified, the premonitory stage is treated. We have delineated special circumstances in the early stage that require immediate seizure control (Table 38–2).10 The transition stage is actually the time within the early stage when compensatory systems become overwhelmed, which marks the beginning of the late stage. This transition stage differs from patient to patient, depending on the circumstances. EEG stages correlate with the clinical stages11 (Table 38–3). Antiepileptic drug (AED) treatment in the early stage controls ...