Status Epilepticus

Comparison of intranasal versus intravenous midazolam for management of status epilepticus in dogs: A multi-center randomized parallel group clinical study

Background

The intranasal (IN) route for rapid drug administration in patients with brain disorders, including status epilepticus, has been investigated. Status epilepticus is an emergency, and the IN route offers a valuable alternative to other routes, especially when these fail.

Objectives

To compare IN versus IV midazolam (MDZ) at the same dosage (0.2 mg/kg) for controlling status epilepticus in dogs.

Animals

Client‐owned dogs (n = 44) with idiopathic epilepsy, structural epilepsy, or epilepsy of unknown origin manifesting as status epilepticus.

Methods

Randomized parallel group clinical trial. Patients were randomly allocated to the IN‐MDZ (n = 21) or IV‐MDZ (n = 23) group. Number of successfully treated cases (defined as seizure cessation within 5 minutes and lasting for ≥10 minutes), seizure cessation time, and adverse effects were recorded. Comparisons were performed using the Fisher's exact and Wilcoxon rank sum tests with statistical significance set at α < .05.

Results

IN‐MDZ and IV‐MDZ successfully stopped status epilepticus in 76% and 61% of cases, respectively (P = .34). The median seizure cessation time was 33 and 64 seconds for IN‐MDZ and IV‐MDZ, respectively (P = .63). When the time to place an IV catheter was taken into account, IN‐MDZ (100 seconds) was superior (P = .04) to IV‐MDZ (270 seconds). Sedation and ataxia were seen in 88% and 79% of the dogs treated with IN‐MDZ and IV‐MDZ, respectively.

Conclusions and Clinical Importance

Both routes are quick, safe, and effective for controlling status epilepticus. However, the IN route demonstrated superiority when the time needed to place an IV catheter was taken into account.

Intranasal Midazolam versus Rectal Diazepam for the Management of Canine Status Epilepticus: A Multicenter Randomized Parallel-Group Clinical Trial

Background

Intranasal administration of benzodiazepines has shown superiority over rectal administration for terminating emergency epileptic seizures in human trials. No such clinical trials have been performed in dogs.

Objective

To evaluate the clinical efficacy of intranasal midazolam (IN‐MDZ), via a mucosal atomization device, as a first‐line management option for canine status epilepticus and compare it to rectal administration of diazepam (R‐DZP) for controlling status epilepticus before intravenous access is available.

Animals

Client‐owned dogs with idiopathic or structural epilepsy manifesting status epilepticus within a hospital environment were used. Dogs were randomly allocated to treatment with IN‐MDZ (n = 20) or R‐DZP (n = 15).

Methods

Randomized parallel‐group clinical trial. Seizure cessation time and adverse effects were recorded. For each dog, treatment was considered successful if the seizure ceased within 5 minutes and did not recur within 10 minutes after administration. The 95% confidence interval was used to detect the true population of dogs that were successfully treated. The Fisher's 2‐tailed exact test was used to compare the 2 groups, and the results were considered statistically significant if P < .05.

Results

IN‐MDZ and R‐DZP terminated status epilepticus in 70% (14/20) and 20% (3/15) of cases, respectively (P = .0059). All dogs showed sedation and ataxia.

Conclusions and Clinical Importance

IN‐MDZ is a quick, safe and effective first‐line medication for controlling status epilepticus in dogs and appears superior to R‐DZP. IN‐MDZ might be a valuable treatment option when intravenous access is not available and for treatment of status epilepticus in dogs at home.

Emergent electroencephalogram in the intensive care unit: indications and diagnostic yield

Our aim was to study the frequency and reasons an emergent electroencephalogram (EmEEG) is ordered in the ICUs compared to the hospital ward, examine its usefulness and find predictive variables for its results. We retrospectively identified all electroencephalograms ordered between December 1997 and March 2002 and performed within 1 hour. The tests ordered from four ICUs were compared with those ordered from the Ward beds, and predictive models were developed for the results based on clinical variables. We also compared the EmEEGs ordered by the Neuro-ICU to those from the other Units. The ICUs ordered 129 (49.4%) of all EmEEGs during the study period. The NICU ordered 32 tests. The most frequent reason for obtaining the test was to rule out status epilepticus (68.2%). The NICU ordered more frequently the test to exclude non-convulsive status than the other ICUs. Compared to non-ICU, ICU patients with head trauma or post cardiopulmonary arrest had more tests and patients with stroke fewer. Convulsive status epilepticus and generalized slowing were found more frequently in the ICUs, and normal EEG, interictal epileptiform activity or focal non-epileptic slowing were more frequent in the non-ICU cases. In at least 12.4% of ICU patients, the test was expected to lead to an anti-epileptic management change. Cardiopulmonary arrest and age were predictive of any epileptic activity on the EEG in ICU patients. In conclusion, in our institution EmEEG is ordered by the ICUs in two thirds of the cases to exclude status epilepticus. Although status epilepticus is confirmed more frequently in the ICUs than on the Ward, the most frequent finding remains generalized slowing, which is found in half of the ICU-ordered EmEEGs. A conservative estimation is that EmEEG will lead to medication change in at least 1 out of 8 ICU patients. Cardioopulmonary arrest is predictive of epileptic activity and a prolonged EmEEG may also increase the yield.

Acute management of seizures in the syndromes of idiopathic generalized epilepsies

Three of the seizure types (myoclonic, absence, and generalized tonic-clonic) and syndromes associated with idiopathic generalized or genetic epilepsies can present an acute status epilepticus picture that requires acute therapy. These are not the usual seizures observed in status epilepticus because most of these patients have secondary generalized or symptomatic generalized convulsive seizures. In this review, I discuss the unique presentation and treatment options for the acute management of seizures in the syndromes of idiopathic generalized epilepsy (IGE), with special emphasis on the seizures of status epilepticus, which persist over time or occur in a series without recovery of consciousness.

An animal model of nonconvulsive status epilepticus: a contribution to clinical controversies

PURPOSE

To characterize electroencephalographic and behavioral effects as well as electrophysiologic and morphologic consequences of a subconvulsive dose of pilocarpine in lithium chloride-pretreated rats.

METHODS

Pilocarpine (15 mg/kg) was administered intraperitoneally to adult rats pretreated with lithium chloride (3 mEq/kg, i.p.). Behavior was observed for 2 h and videotaped in three consecutive sessions. At the same time, EEG was recorded from the sensorimotor cortex and the dorsal hippocampus. Threshold intensities of currents necessary to elicit hippocampal afterdischarges were determined 24 h and 1 week after the pilocarpine administration. The brains were histologically examined 1 week after pilocarpine administration using Nissl stain.

RESULTS

Pilocarpine induced time-limited nonconvulsive status epilepticus (NCSE). Epileptic EEG activity concurrent with prominent behavioral features was observed both in the neocortex and, predominantly, in the hippocampus. No changes in afterdischarge thresholds were observed in the dorsal hippocampus 24 h and 1 week after NCSE. One week after NCSE, seizure-related brain damage was found mainly in the motor neocortical fields.

CONCLUSIONS

Pilocarpine-induced NCSE in rats strongly resembles a short-term human complex partial status epilepticus. Our animal model is suitable for studying the possible adverse effects of prolonged nonconvulsive seizures.

Comparison of plasma benzodiazepine concentrations following intranasal and intravenous administration of diazepam to dogs

OBJECTIVE

To determine whether plasma concentrations of benzodiazepines (BDZ) in dogs following intranasal (IN) administration of diazepam are comparable to concentrations following IV administration.

ANIMALS

6 (4 male, 2 female) healthy adult Greyhounds.

PROCEDURE

Dogs were randomly assigned to 2 groups of 3 dogs in a crossover design. Diazepam (0.5 mg/kg of body weight) was administered intravenously to dogs in group 1 and intranasally to dogs in group 2. Blood was collected from the jugular vein of each dog into tubes containing lithium heparin before and 3, 6, 9, 12, 15, 20, 30, 60, 120, 240, and 480 minutes following diazepam administration. After a 4-day washout period, dogs in group 1 received diazepam intranasally, dogs in group 2 received diazepam intravenously, and blood was again collected. Plasma concentration of BDZ was determined by use of a fluorescence polarization immunoassay.

RESULTS

Mean (+/- SD) peak plasma concentration of BDZ following IV administration (1,316 +/- 216 microg/L) was greater than that following IN administration (448 +/- 41 microg/L). Time to peak concentration was < or = 3 minutes following IV administration and 4.5 +/- 1.5 minutes following IN administration. Mean bioavailability of BDZ following IN administration was 80 +/- 9%.

CONCLUSIONS AND CLINICAL RELEVANCE

Diazepam is rapidly and efficiently absorbed following IN administration of the parenteral formulation. Plasma concentrations match or exceed the suggested therapeutic concentration (300 microg/L). Intranasal administration of diazepam may be useful for treatment of seizures in dogs by owners or when intravenous access is not readily available.

Paradoxic response to diazepam in complex partial status epilepticus

BACKGROUND

Antiepileptics including benzodiazepines have long been recognized to provoke seizures and precipitate status epilepticus occasionally. This has a special clinical importance in the case of diazepam because of its use as first choice medication in its management. This report is intended to highlight the clinical importance of such a situation.

METHODS

The clinical course of a 28-year old man with complex partial status, which lasted for two months, is described in detail.

RESULTS

Paradoxic response to diazepam was documented under EEG monitoring. A similar response was also noted for midazolam, and had probably contributed in exacerbating and prolonging the duration of status.

CONCLUSION

Paradoxic response to diazepam and midazolam is rare, but may be under-recognized. It should be considered in the setting of refractory status epilepticus.

Midazolam and pentobarbital for refractory status epilepticus

Status epilepticus, a serious, life-threatening emergency characterized by prolonged seizure activity, occurs most commonly in pediatric patients. Although initial therapies with agents such as diazepam, phenytoin, or phenobarbital generally terminate seizure activity within 30-60 minutes, patients with refractory status epilepticus (RSE) lasting longer require additional intervention. High-dose pentobarbital has been the most commonly prescribed agent for the management of RSE in children; however, midazolam has emerged as a new treatment option. This review compares the use of midazolam with pentobarbital in published reports of pediatric RSE. Both drugs effectively terminated refractory seizure activity, although pentobarbital use was complicated by hypotension, delayed recovery, pneumonia, and other adverse effects. Midazolam use was effective and well tolerated, affirming its value in pediatric RSE management.

Lidocaine in the treatment of status epilepticus

Intravenous lidocaine has the potential to control seizures. This article reviews the available evidence related to lidocaine's efficacy and clarifies its potential role in the management of status epilepticus (SE). Although there are no large, double-blind, placebo-controlled studies of lidocaine's efficacy in SE, numerous case reports and case series support its use. Most of the reported cases involve patients who were refractory to multiple antiseizure medications. Additional support for lidocaine's efficacy in SE comes from the pediatric literature, where lidocaine has been very effective in controlling SE in neonates who have not responded to barbiturates. Initial lidocaine doses used to stop seizures have ranged from 1 to 3 mg/kg. Most reports recommend a maintenance infusion of lidocaine after initial termination of SE, and a continuous infusion is almost universally recommended for neonates. Toxicity from a 1.5-2.0 mg/kg dose of lidocaine for the control of SE is rare; the authors found only 1 case of a possible side effect at that dose. The article provides a 5-step approach to treating SE that includes lidocaine.

Neuroactive steroids protect against pilocarpine- and kainic acid-induced limbic seizures and status epilepticus in mice

Several structurally related metabolites of progesterone (3 alpha-hydroxy pregnane-20-ones) and deoxycorticosterone (3 alpha-hydroxy pregnane-21-diol-20-ones) and their 3 beta-epimers were evaluated for protective activity against pilocarpine-, kainic acid- and N-methyl-D-aspartate (NMDA)-induced seizures in mice. Steroids with the 3-hydroxy group in the alpha-position and 5-H in the alpha- or beta-configurations were highly effective in protecting against pilocarpine (416 mg/kg, s.c.)-induced limbic motor seizures and status epilepticus (ED50 values, 7.0-18.7 mg/kg, i.p.). The corresponding epimers with the 3-hydroxy group in the beta-position were also effective but less potent (ED50 values, 33.8-63.5, i.p.). Although the neuroactive steroids were considerably less potent than the benzodiazepine clonazepam in protecting against pilocarpine seizures, steroids with the 5 alpha,3 alpha-configuration had comparable or higher protective index values (TD50 for motor impairment divided by ED50 for seizure protection) than clonazepam, indicating that some neuroactive steroids may have lower relative toxicity. Steroids with the 5 alpha,3 alpha- or 5 beta,3 alpha-configurations also produced a dose-dependent delay in the onset of limbic seizures induced by kainic acid (32 mg/kg, s.c.), but did not completely protect against the seizures. However, when a second dose of the steroid was administered 1 hr after the first dose, complete protection from the kainic acid-induced limbic seizures and status epilepticus was obtained. The steroids also caused a dose-dependent delay in NMDA (257 mg/kg, s.c.)-induced lethality, but did not completely protect against NMDA seizures or lethality. We conclude that neuroactive steroids are highly effective in protecting against pilocarpine- and kainic acid-induced seizures and status epilepticus in mice, and may be of utility in the treatment of some forms of status epilepticus in humans.

Defusing status epilepticus

The risk of brain neuron death supersedes that of physical harm due to muscle spasms. In fact, immediate induction of neuromuscular paralysis impedes monitoring of anticonvulsant therapy, which can be empiric but should follow a predetermined, sequential protocol so that seizures can be terminated quickly.