Clinical Review

Management of Status Epilepticus in Adults


 

From the Johns Hopkins Hospital, Baltimore, MD (Dr. Ramadan), and the Henry Ford Hospital, Detroit, MI (Dr. Varelas).

 

ABSTRACT

• Objective: To review the management of status epilepticus (SE).

• Methods: Review of the literature.

• Results: SE is a relatively common condition that accounts for 3% to 5% of all emergency department evaluations for seizure disorders and occurs in 2% to 16% of all epilepsy patients. The 3 most common etiologies are low levels of antiepileptic drugs, remote symptomatic etiologies, and cerebrovascular accidents. The majority of SEs are convulsant, but there is growing awareness of non-convulsive SEs, which can be diagnosed only via electroencephalogram. Management, which must be initiated at the earliest possible time, has evolved to incorporate pre-hospital measures and 4 treatment stages, with supportive measures and benzodiazepine administration remaining the mainstay initially and followed by older and newer antiepileptic drugs and anesthetics for resistant cases.

• Conclusion: SE is a neurological emergency that still carries significant mortality and morbidity if not treated immediately and properly.

 

Key words:  status epilepticus; seizures; convulsive status epilepticus; nonconvulsive status epilepticus .

 

Status epilepticus (SE) is a relatively common condition that accounts for 3% to 5% of all emergency department (ED) evaluations for seizure disorders and occurs in 2% to 16% of all epilepsy patients [1]. It remains a major neurological emergency that, if not properly and timely treated, leads to death or permanent neurological injury. Since most of patients with convulsive SE are admitted to the hospital via the ED and are then transferred to the intensive care unit (ICU), our focus in this review will be on the latter.

Although only a handful prospective, randomized studies have been reported, guidelines on SE have been published in Europe [2] and the US [3,4]. In this paper, we review the evolving definition and types of SE, its incidence, etiology, and pathophysiology, its diagnosis and treatment algorithms, and its outcome. Our goal is to provide the reader with a concise but thorough review of this still lethal neurological emergency.

 

Definitions

The International Classification of Epileptic Seizures had previously defined SE as any seizure lasting ≥ 30 minutes or intermittent seizures lasting for > 30 min without recovery of consciousness interictally [5,6]. More recently, a duration of 5 or more minutes of (a) continuous seizures or (b) 2 or more discrete seizures with incomplete recovery of consciousness in-between, proposed by Lowenstein [3,7], offers the advantage of incorporating new knowledge. The shortening of the convulsive period to 5 minutes was based on the fact that the majority of tonic-clonic seizures last for only 1 to 2 minutes, that those lasting > 5 minutes do not stop spontaneously [8], that permanent neuronal injury occurs before 30 minutes, and that refractoriness to treatment increases with longer seizure duration [9].

Refractory SE (RSE) has been defined as SE not controlled after adequate doses of an initial benzodiazepine followed by a second acceptable antiepileptic drug (AED) or SE not controlled after the initial parenteral therapy with a minimum number of standard “front-line” AEDs (either 2 or 3) or SE with a minimum duration of seizures that persist despite treatment (eg, at least or 2 hours) [3,10]. Super-refractory SE (SRSE) is defined as SE that continues or recurs 24 hours or more after the onset of anesthetic therapy or recurs on the reduction or withdrawal of anesthesia [11].

Non-convulsive SE (NCSE) is defined as the presence of altered consciousness or behavior for ≥ 30 minutes, the absence of overt clinical signs of convulsive activity during that period, and the electroencephalographic (EEG) confirmation of seizures or activity that responds to treatment together with improvement of consciousness [12–15]. Two major types of NCSE can be encountered: the one in patients with epileptic encephalopathy/coma and the one in patients with absence or complex partial seizures, who are not usually admitted to ICU and are functional yet impaired. Because of the confusion between these 2 extremes in the NCSE spectrum, working criteria for standardization of reporting, utilizing the frequency of electroencephalographic epileptiform discharges or delta/theta waveforms have been proposed [15]. A recent compendium of 123 cases of NCSE with clinical descriptions and EEG patterns following a syndromic classification approach has also been published [16].

 

Types of SE

Three major categories of SE have been described: generalized convulsive SE (GCSE), focal motor SE (FMSE or epilepsia partialis continua [EPC]) of Kojevnikov, and NCSE. GCSE and FMSE are easily recognized due to overt convulsions. NCSE, however, has a more obscure phenotype

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