Status Epilepticus

An alternative perspective on the management of status epilepticus

The definition of status epilepticus (SE) has been reduced from 30 minutes to 5 minutes and this article questions if treatment should not be offered before reaching that window. After provision of first aid, benzodiazepines (BDZ) are the initial form of intervention, with either nasal or buccal midazolam being favored for nonprofessionals. Proper patient supervision, including admission to an intensive care unit for more difficult patients, is endorsed, and the need to warn nonprofessionals of the potential risk of respiratory depression is imperative. The article criticizes the use of phenytoin as the antiepileptic medication (AEM) with which to load patients, as it is no longer a first-line AEM, and argues in favor of using a first-line AEM such as valproate or carbamazepine, or preferably the AEM that previously proved efficacious in a patient with known epilepsy who was noncompliant. Alternative routes of administration of AEMs are discussed, and the use of blood level monitoring, as an adjunct to management, to protect against further episodes of SE, is supported. Touched on in this article are the use of some of the newer AEMs in the management of SE and exploration of treatment strategies that acknowledge that treatment must also include patient education that incorporates techniques to enhance compliance.

Valproate is an effective, well-tolerated drug for treatment of status epilepticus/serial attacks in adults

OBJECTIVE

Status epilepticus (SE) and serial attacks (SA) represent neurological emergencies, and mortality rate for SE/SA is high, ranging from 3% to 25%, depending on cause and co-morbidity. As SE/SA become more refractory to treatment over time, rapid, appropriate treatment is extremely important. Here, we report a prospective registration of the effect of intravenous (IV) valproate (VPA) on SE/SA in a group of Norwegian patients.

PATIENTS AND METHODS

Forty-one adult patients (18 males, 23 females) were included in the study. All had previously been unsuccessfully treated with diazepam. For 19, the main SE/SA seizure type was generalized tonic-clonic, while 16 had complex-partial seizures. Six had seizures that were difficult to classify. The treatment protocol recommended 25 mg/kg of VPA loading dose over 30 min, followed by continuous infusion of 100 mg/h for at least 24 h, then per oral administration. If seizures persisted after the loading dose, general anaesthesia (barbiturates/propofol/midazolam) was administered.

RESULTS

No serious side effects were reported. In 76% of the cases (31 of 41), SE/SA stopped and anaesthesia was not required. Of the patients treated within 3 h, only 5% needed anaesthesia, whereas of those treated after 3-24 h, 38% needed anaesthesia. Of those who waited for more than 24 h before treatment, 60% required anaesthesia. Furthermore, 60% of the patients who needed anaesthesia were given loading doses below 2100 mg.

CONCLUSIONS

VPA seems to be a safe, effective treatment of SE/SA, but efficacy is dependent on time lapse between symptoms and VPA treatment, and administration of a sufficiently high loading dose.

Adenosine acting via A1 receptors, controls the transition to status epilepticus-like behaviour in an in vitro model of epilepsy

Adenosine has powerful inhibitory effects in the central nervous system. In this study, we aim to understand how adenosine controls the progression of seizure-like events (SLEs) in a seizure-prone region of the brain, the entorhinal cortex. We chose to use a low Mg(2+) model of epilepsy in an in vitro slice preparation where, in the entorhinal cortex, SLEs progress into a type of epileptiform activity called late recurrent discharges (LRDs) that bear resemblance to status epilepticus. Adenosine, acting via its A1 receptor, exerted powerful inhibitory effects to prevent the spontaneous progression to LRDs while the potent A1 receptor antagonist, DPCPX, accelerated the progression in a concentration dependent manner. The spontaneous progression from SLEs to LRDs was associated with a decline in total cellular ATP levels and studies with metabolic inhibitors indicated a key role for the production of endogenous adenosine from ATP. We therefore hypothesise that when ATP becomes rate limiting, extracellular adenosine levels fall, the normal inhibitory brake is removed and the progression from SLEs to LRDs or status epilepticus-like activity can ensue. Moreover, under these conditions, inhibition of the adenine nucleotide salvage pathways reversed the status epilepticus-like activity. Our findings suggest a powerful role for adenosine for the control of the progression to status epilepticus-like activity in an epilepsy model that is refractory to most anti-epileptic drugs. On this basis, manipulation of adenine nucleotide metabolism may represent a potential therapeutic approach for the treatment of status epilepticus.

Diagnosis and Treatment of Nonconvulsive Status Epilepticus in an Intensive Care Unit Setting

Nonconvulsive status epilepticus (NCSE) in adults is a heterogeneous epileptic emergency and includes absence status (AS), complex-partial status epilepticus (CPSE), and the status epilepticus of epileptic encephalopathy (SEEE). The latter seems to be strikingly frequent among patients in intensive care units (ICU). Diagnosis of NCSE is difficult, but has to be made quickly. It relies on clinical signs and a confirmation electroencephalography (EEG). According to the different etiologies and outcomes of AS, CPSE, and SEEE, treatment has to be individually adapted, but needs to follow some basic principles--treatment should take place in the ICU and be monitored by continuous EEG. With a few exceptions, the first drug is an intravenous benzodiazepine, mainly lorazepam. Intravenous fosphenytoin or phenytoin or valproate may follow next. If some forms of NCSE are resistant to first- and second-line treatments, single or combinations of anesthetics and enteral antiepileptic drugs (AEDs) may be added. This opinion is not evidence-based, and randomized controlled prospective trials to evaluate optimal treatment of NCSE are of first priority.