Intravenous midazolam for the treatment of refractory status epilepticus

Treatment of Refractory Convulsive Status Epilepticus: A Comprehensive Review by the American Epilepsy Society Treatments Committee

Purpose:

Established tonic–clonic status epilepticus (SE) does not stop in one-third of patients when treated with an intravenous (IV) benzodiazepine bolus followed by a loading dose of a second antiseizure medication (ASM). These patients have refractory status epilepticus (RSE) and a high risk of morbidity and death. For patients with convulsive refractory status epilepticus (CRSE), we sought to determine the strength of evidence for 8 parenteral ASMs used as third-line treatment in stopping clinical CRSE.

Methods:

A structured literature search (MEDLINE, Embase, CENTRAL, CINAHL) was performed to identify original studies on the treatment of CRSE in children and adults using IV brivaracetam, ketamine, lacosamide, levetiracetam (LEV), midazolam (MDZ), pentobarbital (PTB; and thiopental), propofol (PRO), and valproic acid (VPA). Adrenocorticotropic hormone (ACTH), corticosteroids, intravenous immunoglobulin (IVIg), magnesium sulfate, and pyridoxine were added to determine the effectiveness in treating hard-to-control seizures in special circumstances. Studies were evaluated by predefined criteria and were classified by strength of evidence in stopping clinical CRSE (either as the last ASM added or compared to another ASM) according to the 2017 American Academy of Neurology process.

Results:

No studies exist on the use of ACTH, corticosteroids, or IVIg for the treatment of CRSE. Small series and case reports exist on the use of these agents in the treatment of RSE of suspected immune etiology, severe epileptic encephalopathies, and rare epilepsy syndromes. For adults with CRSE, insufficient evidence exists on the effectiveness of brivaracetam (level U; 4 class IV studies). For children and adults with CRSE, insufficient evidence exists on the effectiveness of ketamine (level U; 25 class IV studies). For children and adults with CRSE, it is possible that lacosamide is effective at stopping RSE (level C; 2 class III, 14 class IV studies). For children with CRSE, insufficient evidence exists that LEV and VPA are equally effective (level U, 1 class III study). For adults with CRSE, insufficient evidence exists to support the effectiveness of LEV (level U; 2 class IV studies). Magnesium sulfate may be effective in the treatment of eclampsia, but there are only case reports of its use for CRSE. For children with CRSE, insufficient evidence exists to support either that MDZ and diazepam infusions are equally effective (level U; 1 class III study) or that MDZ infusion and PTB are equally effective (level U; 1 class III study). For adults with CRSE, insufficient evidence exists to support either that MDZ infusion and PRO are equally effective (level U; 1 class III study) or that low-dose and high-dose MDZ infusions are equally effective (level U; 1 class III study). For children and adults with CRSE, insufficient evidence exists to support that MDZ is effective as the last drug added (level U; 29 class IV studies). For adults with CRSE, insufficient evidence exists to support that PTB and PRO are equally effective (level U; 1 class III study). For adults and children with CRSE, insufficient evidence exists to support that PTB is effective as the last ASM added (level U; 42 class IV studies). For CRSE, insufficient evidence exists to support that PRO is effective as the last ASM used (level U; 26 class IV studies). No pediatric-only studies exist on the use of PRO for CRSE, and many guidelines do not recommend its use in children aged <16 years. Pyridoxine-dependent and pyridoxine-responsive epilepsies should be considered in children presenting between birth and age 3 years with refractory seizures and no imaging lesion or other acquired cause of seizures. For children with CRSE, insufficient evidence exists that VPA and diazepam infusion are equally effective (level U, 1 class III study). No class I to III studies have been reported in adults treated with VPA for CRSE. In comparison, for children and adults with established convulsive SE (ie, not RSE), after an initial benzodiazepine, it is likely that loading doses of LEV 60 mg/kg, VPA 40 mg/kg, and fosphenytoin 20 mg PE/kg are equally effective at stopping SE (level B, 1 class I study).

Conclusions:

Mostly insufficient evidence exists on the efficacy of stopping clinical CRSE using brivaracetam, lacosamide, LEV, valproate, ketamine, MDZ, PTB, and PRO either as the last ASM or compared to others of these drugs. Adrenocorticotropic hormone, IVIg, corticosteroids, magnesium sulfate, and pyridoxine have been used in special situations but have not been studied for CRSE. For the treatment of established convulsive SE (ie, not RSE), LEV, VPA, and fosphenytoin are likely equally effective, but whether this is also true for CRSE is unknown. Triple-masked, randomized controlled trials are needed to compare the effectiveness of parenteral anesthetizing and nonanesthetizing ASMs in the treatment of CRSE.

Updates in Refractory Status Epilepticus

Refractory status epilepticus is defined as persistent seizures despite appropriate use of two intravenous medications, one of which is a benzodiazepine. It can be seen in up to 40% of cases of status epilepticus with an acute symptomatic etiology as the most likely cause. New-onset refractory status epilepticus (NORSE) is a recently coined term for refractory status epilepticus where no apparent cause is found after initial testing. A large proportion of NORSE cases are eventually found to have an autoimmune etiology needing immunomodulatory treatment. Management of refractory status epilepticus involves treatment of an underlying etiology in addition to intravenous anesthetics and antiepileptic drugs. Alternative treatment options including diet therapies, electroconvulsive therapy, and surgical resection in case of a focal lesion should be considered. Short-term and long-term outcomes tend to be poor with significant morbidity and mortality with only one-third of patients reaching baseline neurological status.

Does burst-suppression achieve seizure control in refractory status epilepticus?

Background

The general principles in the administration of anesthetic drugs entail not only the suppression of seizure activity but also the achievement of electroencephalography burst suppression (BS). However, previous studies have reported conflicting results, possibly owing to the inclusion of various anesthetic agents, not all patients undergoing continuous electroencephalography (cEEG), and the inclusion of anoxic encephalopathy. This study aimed to analyze the effects of midazolam-induced BS on the occurrence outcomes in refractory status epilepticus patients.

Methods

Based on a prospective database of patients who had been diagnosed with status epilepticus via cEEG, multivariate Poisson regression modules were used to estimate the effect of midazolam-induced BS on breakthrough seizure, withdrawal seizure, intra-hospital complications, functional outcome at 3 months, and mortality. Modules were based on a pre-compiled directed acyclic graph (DAG).

Results

We included 51 non-anoxic encephalopathy, refractory status epilepticus patients. Burst suppression was achieved in 26 patients (51%); 25 patients (49%) had non-burst suppression on their cEEG. Breakthrough seizure was less often seen in the burst suppression group than in the non-burst suppression group. The incidence risk ratio [IRR] was 0.30 (95% confidence interval = 0.13–0.74). There was weak evidence of an association between BS and increased withdrawal seizure, but no association between BS and intra-hospital complications, mortality or functional outcomes was observed.

Conclusion

This study provides evidence that BS is safe and associated with less breakthrough seizures. Additionally, it was not associated with an increased rate of intra-hospital complications or long-term outcomes.

A Comparative Study of Midazolam and Target-Controlled Propofol Infusion in the Treatment of Refractory Status Epilepticus

Background:

The recommended treatment for refractory status epilepticus (RSE) is the use of anesthetic agents, but evidence regarding the agent of choice is lacking. This study was designed to compare target-controlled infusion of propofol versus midazolam for the treatment of RSE regarding seizure control and complications.

Methods:

This prospective, randomized study recruited 23 adult patients with RSE due to any etiology and treated with either propofol or midazolam titrated to clinical seizure cessation and gradual tapering thereafter. The primary outcome measure was seizure control and the secondary outcomes were duration of the Intensive Care Unit stay and duration of mechanical ventilation, occurrence of super RSE (SRSE), and complications.

Results:

We recruited 23 patients (male:female = 18:5) into this study (propofol Group-11; midazolam Group-12). Overall, seizure control was noted in 34.8%, with successful seizure control in 45% of patients in the propofol group and 25% in midazolam group (P = 0.4). Mortality was similar in both the groups (propofol group [8/11; 72.7%] compared to the midazolam group [7/12; 58.3%] [P = 0.667]). The duration of hospital stay was significantly shorter in the propofol group compared to midazolam (P = 0.02). The overall incidence of SRSE was 69.5% in this study. The complication rate was not significantly different between the groups.

Conclusions:

The choice of anesthetic agent does not seem to affect the overall outcome in RSE and SRSE. Target-controlled propofol infusion was found to be equal in its efficacy to midazolam for the treatment of RSE. High mortality might be due to SRSE secondary to the underlying brain pathology.

Management of Status Epilepticus

Status epilepticus is due to a range of insults to the central nervous system and results in significant mortality rates, especially in the elderly. We review the current management of this disorder in light of the latest developments from recent trials and guidelines. Important principles in management includes early recognition of status epilepticus, identification of the underlying cause and prompt treatment to terminate seizures and reduce complications. The differentiation diagnosis, role of electroencephalographic monitoring and different treatment regimes are examined.

Pharmacotherapy for Alcohol Withdrawal

This feature examines the impact of pharmacologic interventions on the treatment of the critically ill patient — an area of health care that has become increasingly complex. Recent advances in drug therapy for adult ICU patients (including evolving and controversial data) will be reviewed and assessed in terms of clinical, humanistic, and economic outcomes. Direct questions or comments to Gil Fraser, PharmD, at fraseg@mmc.org .

Status Epilepticus and Beyond: A Clinical Review of Status Epilepticus and an Update on Current Management Strategies in Super-refractory Status Epilepticus

Status epilepticus and refractory status epilepticus represent some of the most complex conditions encountered in the neurological intensive care unit. Challenges in management are common as treatment options become limited and prolonged hospital courses are accompanied by complications and worsening patient outcomes. Antiepileptic drug treatments have become increasingly complex. Rational polytherapy should consider the pharmacodynamics and kinetics of medications. When seizures cannot be controlled with medical therapy, alternative treatments, including early surgical evaluation can be considered; however, evidence is limited. This review provides a brief overview of status epilepticus, and a recent update on the management of refractory status epilepticus based on evidence from the literature, evidence-based guidelines, and experiences at our institution.

Continuous Infusion Antiepileptic Medications for Refractory Status Epilepticus: A Review for Nurses

Status epilepticus requires treatment with emergent initial therapy with a benzodiazepine and urgent control therapy with an additional antiepileptic drug (AED) to terminate clinical and/or electrographic seizure activity. However, nearly one-third of patients will prove refractory to the aforementioned therapies and are prone to a higher degree of neuronal injury, resistance to pharmacotherapy, and death. Current guidelines for refractory status epilepticus (RSE) recommend initiating a continuous intravenous (CIV) anesthetic over bolus dosing with a different AED. Continuous intravenous agents most commonly used for this indication include midazolam, propofol, and pentobarbital, but ketamine is an alternative option. Comparative studies illustrating the optimal agent are lacking, and selection is often based on adverse effect profiles and patient-specific factors. In addition, dosing and titration are largely based on small studies and expert opinion with continuous electroencephalogram monitoring used to guide intensity and duration of treatment. Nonetheless, the doses required to halt seizure activity are likely to produce profound adverse effects that clinicians should anticipate and combat. The purpose of this review was to summarize the available RSE literature focusing on CIV midazolam, pentobarbital, propofol, and ketamine, and to serve as a primer for nurses providing care to these patients.

Status Epilepticus: What's New?

The emergent evaluation and treatment of generalized convulsive status epilepticus presents challenges for emergency physicians. This disease is one of the few in which minutes can mean the difference between life and significant morbidity and mortality. It is imperative to use parallel processing and have multiple treatment options planned in advance, in case the current treatment is not successful. There is also benefit to exploring, or initiating, treatment algorithms to standardize the care for these critically ill patients.

Cyclic Antidepressant Poisoning: A Review and Case Report

Although newer cyclic antidepressants have been introduced over the past several years, the tricyclic antidepressants (TCAs) continue to be the leading cause of morbidity from drug overdose in the United States. Overdose features depend on the particular cyclic antidepressant ingested and its pharmacological properties, and can include CNS depression, cardiac arrhythmias, hypotension, seizures, and anticholinergic symptomatology. Life-threatening symptomatology almost always begins within 2 hours, and certainly within 6 hours, after arrival to the emergency department. Plasma TCA levels are unreliable predictors of TCA toxicity and are not recommended. An ECG with a prolonged QRS complex more than 100 msec seems to be the best indicator of serious sequelae with TCAs. Management consists of stabilization of vital signs, gastrointestinal decontamination, intravenous sodium bicarbonate, and supportive care. Agents once thought to be useful for the treatment of cardiac dysrhythmias and seizures such as phenytoin and physostigmine should be avoided. The future of TCA antibody fragments in the treatment of TCA overdose seems promising. Newer and, to some degree, safer antidepressants in overdose have recently been introduced, and they include fluoxetine, trazodone, and sertraline. Amoxapine, bupropion, and maprotiline seem to be as toxic as the TCAs. A significant interaction between cyclic antidepressants and monoamine-oxidase inhibitors exists. Management includes supportive care and basic poison management. Prevention of poisoning seems to be the most logical and effective method of maintaining patient safety. TCAs should be avoided in children younger than 6 years old. All adults with suicidal ideations should receive no more than a 1-week supply (about 1 g) of drug. Finally consideration should be given to using one of the newer, safer antidepressants in all patients with suicidal ideations.

Comparison of Intravenous Anesthetic Agents for the Treatment of Refractory Status Epilepticus

Status epilepticus that cannot be controlled with first- and second-line agents is called refractory status epilepticus (RSE), a condition that is associated with significant morbidity and mortality. Most experts agree that treatment of RSE necessitates the use of continuous infusion intravenous anesthetic drugs such as midazolam, propofol, pentobarbital, thiopental, and ketamine, each of which has its own unique characteristics. This review compares the various anesthetic agents while providing an approach to their use in adult patients, along with possible associated complications.

Treatment of Generalized Convulsive Status Epilepticus in Pediatric Patients

Generalized convulsive status epilepticus (GCSE) is one of the most common neurologic emergencies and can be associated with significant morbidity and mortality if not treated promptly and aggressively. Management of GCSE is staged and generally involves the use of life support measures, identification and management of underlying causes, and rapid initiation of anticonvulsants. The purpose of this article is to review and evaluate published reports regarding the treatment of impending, established, refractory, and super-refractory GCSE in pediatric patients.

Management of refractory status epilepticus in an actively dying patient

No consensus guidelines exist for the treatment of refractory myoclonic status epilepticus or refractory myoclonus in the palliative care setting. Evidence-based guidelines for the general medical population are often neither practical nor applicable at the end of life. Many challenges, including medication availability, route of administration, monitoring, and work-up are all unique to the palliative care setting. Two patients with refractory myoclonus versus refractory myoclonic status epilepticus are described here, illustrating the challenges involved in treatment as well the need for further research for therapy in the palliative care setting.

Midazolam fails to prevent neurological damage in children with convulsive refractory febrile status epilepticus

BACKGROUND

We conducted a retrospective study to compare the outcome of intravenous midazolam infusion without electroencephalography or targeted temperature management and barbiturate coma therapy with electroencephalography and targeted temperature management for treating convulsive refractory febrile status epilepticus.

PATIENTS

Of 49 consecutive convulsive refractory febrile status epilepticus patients admitted to the pediatric intensive care unit of our hospital, 29 were excluded because they received other treatments or because of various underlying illnesses. Thus, eight patients were treated with midazolam and 10 with barbiturate coma therapy using thiamylal. Midazolam-treated patients were intubated only when necessary, whereas barbiturate coma therapy patients were routinely intubated. Continuous electroencephalography monitoring was utilized only for the barbiturate coma group. The titration goal for anesthesia was clinical termination of status epilepticus in the midazolam group and suppression or burst-suppression patterns on electroencephalography in the barbiturate coma group. Normothermia was maintained using blankets and neuromuscular blockade in the barbiturate coma group and using antipyretics in the midazolam group. Prognoses were measured at 1 month after onset; children were classified into poor and good outcome groups.

RESULTS

Good outcome was achieved in all the barbiturate coma group patients and 50% of the midazolam group patients (P = 0.02, Fisher's exact test).

CONCLUSIONS

Although the sample size was small and our study could not determine which protocol element is essential for the neurological outcome, the findings suggest that clinical seizure control using midazolam without continuous electroencephalography monitoring or targeted temperature management is insufficient in preventing neurological damage in children with convulsive refractory febrile status epilepticus.

Clinical pharmacology of midazolam in neonates and children: effect of disease-a review

Midazolam is a benzodiazepine with rapid onset of action and short duration of effect. In healthy neonates the half-life (t_1/2) and the clearance (Cl) are 3.3-fold longer and 3.7-fold smaller, respectively, than in adults. The volume of distribution (Vd) is 1.1 L/kg both in neonates and adults. Midazolam is hydroxylated by CYP3A4 and CYP3A5; the activities of these enzymes surge in the liver in the first weeks of life and thus the metabolic rate of midazolam is lower in neonates than in adults. Midazolam acts as a sedative, as an antiepileptic, for those infants who are refractory to standard antiepileptic therapy, and as an anaesthetic. Information of midazolam as an anaesthetic in infants are very little. Midazolam is usually administered intravenously; when minimal sedation is required, intranasal administration of midazolam is employed. Disease affects the pharmacokinetics of midazolam in neonates; multiple organ failure reduces the Cl of midazolam and mechanical ventilation prolongs the t_1/2 of this drug. ECMO therapy increases t_1/2, Cl, and Vd of midazolam several times. The adverse effects of midazolam in neonates are scarce: pain, tenderness, and thrombophlebitis may occur. Respiratory depression and hypotension appear in a limited percentage of infants following intravenous infusion of midazolam. In conclusion, midazolam is a safe and effective drug which is employed as a sedative, as antiepileptic agent, for infants who are refractory to standard antiepileptic therapy, and as an anaesthetic.

High-dose midazolam infusion for refractory status epilepticus

OBJECTIVE

This study compares 2 treatment protocols allowing low vs high continuous IV midazolam (cIV-MDZ) doses.

METHODS

We compared adults with refractory status epilepticus treated with a protocol allowing for high-dose cIV-MDZ (n = 100; 2002-2011) with those treated with the previous lower-dose cIV-MDZ (n = 29; 1996-2000). We collected data on baseline characteristics, cIV-MDZ doses, seizure control, hospital course, and outcome.

RESULTS

Median maximum cIV-MDZ dose was 0.4 mg/kg/h (interquartile range [IQR] 0.2, 1.0) for the high-dose group and 0.2 mg/kg/h (IQR 0.1, 0.3) for the low-dose group (p < 0.001) with similar duration of infusion. Median time from status epilepticus onset to cIV-MDZ start was 1 day (IQR 1, 3) for the high-dose group and 2 days (IQR 1, 5) for the low-dose group (p = 0.016). "Withdrawal seizures" (occurring within 48 hours of discontinuation of cIV-MDZ) were less frequent in the high-dose group (15% vs 64%, odds ratio 0.10, 95% confidence interval 0.03-0.27). "Ultimate cIV-MDZ failure" (patients requiring change to a different cIV antiepileptic medication) and hospital complications were not different between groups. Hypotension was more frequent with higher cIV-MDZ doses but was not associated with worse outcome. Discharge mortality was lower in the high-dose group (40% vs 62%, odds ratio 0.34, 95% confidence interval 0.13-0.92 in multivariate analysis).

CONCLUSIONS

High-dose cIV-MDZ treatment of refractory status epilepticus can be performed safely, is associated with a lower seizure rate after cIV-MDZ discontinuation, and may be associated with lower mortality than traditional lower-dose protocols.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that midazolam at higher infusion rates is associated with a reduction in seizure recurrence within 48 hours after discontinuation and may be associated with lower mortality.

Guidelines for the evaluation and management of status epilepticus

Status epilepticus (SE) treatment strategies vary substantially from one institution to another due to the lack of data to support one treatment over another. To provide guidance for the acute treatment of SE in critically ill patients, the Neurocritical Care Society organized a writing committee to evaluate the literature and develop an evidence-based and expert consensus practice guideline. Literature searches were conducted using PubMed and studies meeting the criteria established by the writing committee were evaluated. Recommendations were developed based on the literature using standardized assessment methods from the American Heart Association and Grading of Recommendations Assessment, Development, and Evaluation systems, as well as expert opinion when sufficient data were lacking.

Status epilepticus and the use of continuous EEG monitoring in the intensive care unit

PURPOSE OF REVIEW

Status epilepticus (SE) is one of the major neurologic emergencies. Newer data about the genesis and treatment of this condition are available to help improve our understanding and management.

RECENT FINDINGS

Approximately 150,000 cases of generalized convulsive SE occur in the United States each year. Clinically apparent seizures complicate about 8% of intensive care unit admissions, and another 10% of ICU patients suffer electrographic seizures in the course of another critical illness. Some of these cases result from previously under-recognized epileptogenic effects of commonly used drugs, such as cefepime. Continuous EEG (cEEG) recording is necessary for both diagnosis and management in these patients, especially since anticonvulsant drugs may abolish motor activity without stopping seizures. Recent studies have underscored the utility of benzodiazepines as the first-line agents for SE termination. The recently published Rapid Anticonvulsant Medication Prior to Arrival Trial (RAMPART) demonstrates that the more rapidly treatment is administered, the more effective it will be. When SE fails to respond to usual doses of benzodiazepines, it should be considered refractory to conventional anticonvulsants, and a general anesthetic approach is likely to be necessary.

SUMMARY

While definitions have varied, patients should be managed for SE after 5 minutes of seizure activity. Management of a patient with SE involves three phases: termination of SE, prevention of recurrence, and treatment of complications. The typical anticonvulsants have limited ability to terminate SE; lorazepam is the most useful, controlling SE in 65% of patients experiencing generalized convulsive SE. If the first conventional anticonvulsant fails, others are unlikely to be useful, and one of the newer anticonvulsants or a general anesthetic agent should be considered. EEG is crucial in the diagnosis and classification of potential seizures. cEEG monitoring helps to guide anticonvulsant therapy in patients with SE and those with frequent seizures. In addition, cEEG has the potential for presymptomatic diagnosis of delayed neurologic deterioration in patients with subarachnoid hemorrhage and for the differential diagnosis of stroke subtypes, especially when cEEG is subjected to signal processing.

Blood concentrations of midazolam in status epilepticus using an appropriate condition of HPLC

BACKGROUND

The aim of the present study was to determine an index to evaluate the efficacy and safety of midazolam (MDZ) to treat status epilepticus (SE). An original system was therefore developed to measure blood concentrations of MDZ and 1-hydroxymidazolam (1-OHMDZ) as the main metabolite on high-performance liquid chromatography.

METHODS

This system was established through inspection of chromatograms, calibration curves and coefficient of correlations of MDZ. The clinical course of 11 SE patients, ranging from 4 months to 10 years of age, are described. These patients were treated with MDZ and measured at each blood concentration of MDZ. Moreover, patients were evaluated on cranial computed tomography and magnetic resonance imaging and video electroencephalogram (EEG), and it was determined that their seizures disappeared in accordance with the disappearance of convulsions and interictal EEG findings.

RESULTS

Reproducibility was good with this system. The standard curves of MDZ and 1-OHMDZ were almost straight, and the correlation coefficients of MDZ and 1-OHMDZ were r = 0.9999 and r = 0.9998, respectively. The convulsions in nine of 11 SE patients disappeared without side-effects and the blood concentrations of MDZ in all the patients were measured. The mean peak blood concentrations of MDZ and 1-OHMDZ were higher than those reported in other studies.

CONCLUSIONS

The clinical utility of this system has been demonstrated. An index to evaluate the efficacy and safety of MDZ is necessary, and MDZ blood concentrations measured on the present original precise measuring system could help in establishing a plan to successfully treat SE.

Intravenous midazolam in convulsive status epilepticus in children with pharmacoresistant epilepsy

Although the efficacy of midazolam in refractory status epilepticus and as a first-line agent in children with established status epilepticus has been reported, differences in starting doses, continuation method, timing of efficacy assessment, and discontinuation pose limitations in deriving a specific protocol for midazolam use. An audit of clinical experience with a protocol of midazolam as first-line agent for impending status epilepticus (defined as a continuous, generalized, convulsive seizure lasting >5 minutes) in 76 episodes of unprovoked convulsive status epilepticus in children 1-15 years old with treatment-refractory epilepsy demonstrated that: (1) repeated bolus midazolam 0.1mg/kg (every 5 minutes, maximum 5) controlled 91% of events; (2) three bolus doses controlled 89% of the episodes, with minimal chance of response beyond that; (3) treating impending status resulted in lower doses (mean 0.17 mg/kg) than reported and infrequent utilization of additional anticonvulsants (9%); and (4) adverse events were infrequent (respiratory depression 13%, assisted ventilation 3%).

Benzodiazepines in epilepsy: pharmacology and pharmacokinetics

Benzodiazepines (BZDs) remain important agents in the management of epilepsy. They are drugs of first choice for status epilepticus and seizures associated with post-anoxic insult and are also frequently used in the treatment of febrile, acute repetitive and alcohol withdrawal seizures. Clinical advantages of these drugs include rapid onset of action, high efficacy rates and minimal toxicity. Benzodiazepines are used in a variety of clinical situations because they have a broad spectrum of clinical activity and can be administered via several routes. Potential shortcomings of BZDs include tolerance, withdrawal symptoms, adverse events, such as cognitive impairment and sedation, and drug interactions. Benzodiazepines differ in their pharmacologic effects and pharmacokinetic profiles, which dictate how the drugs are used. Among the approximately 35 BZDs available, a select few are used for the management of seizures and epilepsy: clobazam, clonazepam, clorazepate, diazepam, lorazepam and midazolam. Among these BZDs, clorazepate has a unique profile that includes a long half-life of its active metabolite and slow onset of tolerance. Additionally, the pharmacokinetic characteristics of clorazepate (particularly the sustained-release formulation) could theoretically help minimize adverse events. However, larger, controlled studies of clorazepate are needed to further examine its role in the treatment of patients with epilepsy.

Status epilepticus in a hospice inpatient setting

Although evidence-based guidelines on the management of status epilepticus in the general population are available, these cannot be readily applied to hospice inpatients. The treatment of status epilepticus in a hospice setting presents many challenges in terms of choice and availability of drugs, route of administration and availability of monitoring facilities. A case report is presented that illustrates the distinct challenges involved in the management of status epilepticus in this setting. Commonly used antiseizure medications are discussed, with emphasis on the potential benefits and drawbacks in a hospice population.

Pharmacokinetics and clinical efficacy of midazolam in children with severe malaria and convulsions

AIM

To investigate the pharmacokinetics and clinical efficacy of intravenous (IV), intramuscular (IM) and buccal midazolam (MDZ) in children with severe falciparum malaria and convulsions.

METHODS

Thirty-three children with severe malaria and convulsions lasting ≥5 min were given a single dose of MDZ (0.3 mg kg⁻¹) IV (n = 13), IM (n = 12) or via the buccal route (n = 8). Blood samples were collected over 6 h post-dose for determination of plasma MDZ and 1′-hydroxymidazolam concentrations. Plasma concentration–time data were fitted using pharmacokinetic models.

RESULTS

Median (range) MDZ C_max of 481 (258–616), 253 (96–696) and 186 (64–394) ng ml⁻¹ were attained within a median (range) t_max of 10 (5–15), 15 (5–60) and 10 (5–40) min, following IV, IM and buccal administration, respectively. Mean (95% confidence interval) of the pharmacokinetic parameters were: AUC(0,∞) 596 (327, 865), 608 (353, 864) and 518 (294, 741) ng ml⁻¹ h; V_d 0.85 l kg⁻¹; clearance 14.4 ml min⁻¹ kg⁻¹, elimination half-life 1.22 (0.65, 1.8) h, respectively. A single dose of MDZ terminated convulsions in all (100%), 9/12 (75%) and 5/8 (63%) children following IV, IM and buccal administration. Four children (one in the IV, one in the IM and two in the buccal groups) had respiratory depression.

CONCLUSIONS

Administration of MDZ at the currently recommended dose resulted in rapid achievement of therapeutic MDZ concentrations. Although IM and buccal administration of MDZ may be more practical in peripheral healthcare facilities, the efficacy appears to be poorer at the dose used, and a different dosage regimen might improve the efficacy.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Midazolam (MDZ), a water-soluble benzodiazepine, can be administered via several routes, including intravenously (IV), intramuscularly (IM) and buccal routes to terminate convulsions. It may be a suitable alternative to diazepam to stop convulsions in children with severe malaria, especially at peripheral healthcare facilities. The pharmacokinetics of MDZ have not been described in African children, in whom factors such as the aetiology and nutritional status may influence the pharmacokinetics.

WHAT THIS STUDY ADDS

Administration of MDZ (IV, IM, or buccal) at the currently recommended dose (0.3 mg kg⁻¹) resulted in rapid achievement of median maximum plasma concentrations of MDZ within the range 64–616 ng ml⁻¹, with few clinically significant cardio-respiratory effects. A single dose of MDZ rapidly terminated (within 10 min) seizures in all (100%), 9/12 (75%) and 5/8 (63%) children following IV, IM and buccal administration, respectively. Although IM and buccal MDZ may be the preferred treatment for children in the pre-hospital settings the efficacy appears to be poorer.

Treatment of refractory status epilepticus: literature review and a proposed protocol

Refractory status epilepticus describes continuing seizures despite adequate initial pharmacologic treatment. This situation is common in children, but few data are available to guide management. We review the literature related to the pharmacologic treatment and overall management of refractory status epilepticus, including midazolam, pentobarbital, phenobarbital, propofol, inhaled anesthetics, ketamine, valproic acid, topiramate, levetiracetam, pyridoxine, corticosteroids, the ketogenic diet, and electroconvulsive therapy. Based on the available data, we present a sample treatment algorithm that emphasizes the need for rapid therapeutic intervention, employs consecutive medications with different mechanisms of action, and attempts to minimize the risk of hypotension. The initial steps suggest using benzodiazepines and phenytoin. Second steps suggest using levetiracetam or valproic acid, which exert few hemodynamic adverse effects and have multiple mechanisms of action. Additional management strategies that could be employed in tertiary-care settings, such as coma induction guided by continuous electroencephalogram monitoring and surgical options, are also discussed.

Nonconvulsive status epilepticus

Nonconvulsive status epilepticus (NCSE) is a heterogeneous disorder with multiple subtypes. Although attempts have been made to define and classify this disorder, there is yet no universally accepted definition or classification that encompasses all subtypes or electroclinical scenarios. Developing such a classification scheme is becoming increasingly important, because NCSE is more common than previously thought, with a bimodal peak, in children and the elderly. Recent studies have also shown a high incidence of NCSE in the critically ill. Although strong epidemiological data are lacking, NCSE constitutes about 25-50% of all cases of status epilepticus. For the purposes of this review, we propose an etiological classification for NCSE including NCSE in metabolic disorders, NCSE in coma, NCSE in acute cerebral lesions, and NCSE in those with preexisting epilepsy with or without epileptic encephalopathy. NCSE is still underrecognized, yet potentially fatal if untreated. Diagnosis can be established using an electroencephalogram (EEG) in most cases, sometimes requiring continuous monitoring. However, in comatose patients, diagnosis can be difficult, and the EEG can show a variety of rhythmic or periodic patterns, some of which are of unclear significance. Although some subtypes of NCSE are easily treatable, such as absence status epilepticus, others do not respond well to treatment, and debate exists over how aggressively clinicians should treat NCSE. In particular, the appropriate treatment of NCSE in patients who are critically ill and/or comatose is not well established, and large-scale trials are needed. Overall, further work is needed to better define NCSE, to determine which EEG patterns represent NCSE, and to establish treatment paradigms for different subtypes of NCSE.

Seizures and status epilepticus in the critically ill

Seizures represent stereotypic electroencephalographic (EEG) and behavioral paroxysms as a consequence of electrical neurologic derangement. Seizures are usually described as focal or generalized motor convulsions; however, nonconvulsive seizures that occur in the absence of motor activity may escape clinical detection. Because of the admission diagnoses and dramatic physiologic and metabolic derangements common to critically ill patients, the entire spectrum of seizure disorders may be encountered in the ICU. Seizures in the ICU are attributable to primary neurologic pathology or secondary to critical illness and clinical management. For optimal treatment, early diagnosis of the seizure type and its cause is important to ensure appropriate therapy. Convulsive status epilepticus requires emergent treatment before irreversible brain injury and severe metabolic disturbances occur.

Efficacy of intravenous midazolam for status epilepticus in childhood

A retrospective multicenter study was conducted, designed to evaluate the efficacy and safety of midazolam for the treatment of status epilepticus. The subjects were 358 inpatients who received intravenous midazolam therapy for status epilepticus. The mean age was 48.6 +/- 46.5 months. The underlying disorder was epilepsy in 195 cases, and acute symptomatic diseases in 163 (encephalitis or encephalopathy in 88 cases). Midazolam was administered as a bolus dose (0.25 +/- 0.21 mg/kg), followed if necessary by continuous infusion (0.26 +/- 0.25 mg/kg/hr). The bolus injection was effective in 162 (56.6%) of the 286 cases. In the end, seizure suppression was obtained in 231 cases (64.5% of the total). The effectiveness of midazolam was lower in patients in whom midazolam was initiated more than 3 hours after seizure onset, and this tendency was particularly marked in the epilepsy group. During the treatment period, 10 patients died, but none of these deaths were associated with midazolam therapy. The incidence and types of adverse events were consistent with previously reported data. The present results indicate that midazolam is highly effective for the management of status epilepticus, if used sufficiently early after seizure onset.

Comparative Efficacy and Safety of Antiepileptic Drugs for the Treatment of Status Epilepticus

Status epilepticus (SE) is a medical emergency with high mortality rate. Common causes of SE include noncompliance with antiepileptic medications, drug- and alcohol-related etiologies, and central nervous system (CNS) infections. Because prolonged seizures can cause neuronal damage, treatment should be initiated promptly to avoid potential complications. Previous studies support intravenous (IV) lorazepam as first-line therapy and IV phenytoin or fosphenytoin as a second-line medication. If first-and second-line medications fail to control SE, further treatment with propofol, pentobarbital, midazolam, or other medications should be considered. Many of the drugs currently used to control SE are associated with sedation, respiratory suppression, hypotension, cardiac dysrhythmia, and anaphylactic reactions. Therefore, IV valproate or other newer antiepileptic drugs may be considered as an alternative third-line therapy for those who cannot tolerate the hypotensive effects of other anticonvulsants. This paper reviews comparative effectiveness and safety concerns among frequently used medications for SE.

Epidemiology and outcomes of status epilepticus in the elderly

Status epilepticus (SE) is a serious condition of prolonged or repetitive seizures. The annual incidence (86/100,000) of SE in the elderly who are aged 60 and greater is almost twice that of the general population and is even higher in those who are 70 years and older. Either acute or remote symptomatic stroke causes approximately 60% of SE seen in the elderly. SE is associated with a high mortality in the elderly (38%), with a rate approaching 50% in patients older than 80 years of age. Etiology is a strong determinant of mortality in the elderly: mortality approaches 100% in patients with anoxia and 30% in patients with either metabolic disorders, hemorrhages, tumors, or systemic infections. Mortality is almost three times higher in SE associated with acute ischemic stroke than in stroke alone, indicating synergistic effects. Duration of SE is also a factor in mortality. Treatment should be initiated for any convulsive seizure that lasts at least 10 min or is repetitive. An electroencephalogram (EEG) should be promptly obtained so that a diagnosis can be made without delay. Because older patients have a greater likelihood of nondiagnostic findings on routine EEGs, prolonged EEG recordings and inpatient video-EEG monitoring significantly increase the rate of establishing a definitive diagnosis. Nonconvulsive status epilepticus in the elderly is especially difficult to diagnose and should be evaluated with an EEG. Treatment of SE is complicated by altered pharmacokinetics in the elderly. Initial treatments, usually the administration of an intravenous benzodiazepine, have overall success rates of 55% for overt convulsive SE and 14.9% for subtle SE. For refractory SE, little is gained by using additional standard drugs, and general anesthesia with continuous EEG monitoring is recommended.

Treatment of Status Epilepticus in Adults: Guidelines of the Italian League Against Epilepsy

Status epilepticus (SE) is a medical emergency which can lead to significant morbidity and mortality and requires prompt diagnosis and treatment. SE is differentiated into generalized or partial SE on the basis of its electro-clinical manifestations. The guidelines for the management of SE produced by the Italian League against Epilepsy also distinguish three different stages of SE (initial, established and refractory), based on time elapsed since the onset of the condition and responsiveness to previously administered drugs. Treatment should be started as soon as possible, particularly in generalized convulsive SE, and should include general support measures, drugs to suppress epileptic activity and, whenever possible, treatments aimed at relieving the underlying (causative) condition. Benzodiazepines are the first line antiepileptic agents, and i.v. lorazepam is generally preferred because it is associated with a lower risk of early relapses. If benzodiazepines fail to control seizures, i.v. phenytoin is usually indicated, though i.v. phenobarbital or i.v. valproate may also be considered. Refractory SE requires admission to an intensive care unit (ICU) to allow adequate monitoring and support of respiratory, metabolic and hemodynamic functions and cerebral electrical activity. In refractory SE, general anesthesia may be required. Propofol and thiopental represent first line agents in this setting, after careful assessment of potential risks and benefits.

Management of Seizures in the Critically Ill

Seizures in a critically ill patient are not infrequent phenomena. Physicians are perplexed by the wide range of possible cranial or extracranial etiologies, alerted by the risk for further crucial organ compromise if seizures recur, and confused about the treatment options in an environment rich in complex drug interactions and multiple organ dysfunction. The advent of an armamentarium containing multiple new antiepileptic medications complicates the situation further, since several of them have less known mechanisms of action, side effects, or interactions with other intensive care unit (ICU) medications. This review contains useful information regarding the most common etiologies and treatment options for intensivists, consulting neurologists, neurosurgeons, or other specialized physicians treating ICU patients with seizures.

Status epilepticus: pathophysiology and management in adults

As in Clark and Prout's classic work, we identify three phases of generalised convulsive status epilepticus, which we call impending, established, and subtle. We review physiological and subcellular changes that might play a part in the transition from single seizures to status epilepticus and in the development of time-dependent pharmacoresistance. We review the principles underlying the treatment of status epilepticus and suggest that prehospital treatment is beneficial, that therapeutic drugs should be used in rapid sequence according to a defined protocol, and that refractory status epilepticus should be treated with general anaesthesia. We comment on our preference for drugs with a short elimination half-life and discuss some therapeutic choices.

Animal models for the development of new neuropharmacological therapeutics in the status epilepticus

Status epilepticus (SE) is a major medical emergency associated with significant morbidity and mortality. SE is best defined as a continuous, generalized, convulsive seizure lasting > 5 min, or two or more seizures during which the patient does not return to baseline consciousness. The relative efficacy and safety of different drugs in the treatment of human SE should be determined in a prospective, randomized, blinded study. However, complementary animal models of SE are required to answer important questions concerning the treatment of SE because of the obvious difficulties of setting up such studies in clinical emergency conditions. This review offers an overview of the implementation and characteristics of some of the most prevalent animal models of SE currently in use. A description is also provide about how animal models of SE may facilitate the use of neurobiological techniques to successfully address critical questions in the drug treatment of SE. In particular, the experience with recently introduced drugs such as intravenous valproate will be addressed. Finally, the importance of some animal models and pharmacological approaches is explained and we discuss their impact in the development of therapeutic strategies to improve pharmacological treatment for SE is discussed.

Refractory status epilepticus

PURPOSE OF REVIEW

Although conventional anticonvulsant agents can terminate status epilepticus in most cases, a substantial minority of patients develops medically refractory status and requires more aggressive care. This review explores the options available.

RECENT FINDINGS

Increasing numbers of previously unexpected etiologies for refractory status epilepticus continue to be reported. There are also some promising new therapies on the horizon, both for the short and the longer terms.

SUMMARY

Refractory status epilepticus, while a challenge to the intensivist, can be treated with drugs that are commonly used by intensivists. The cooperation of an interested electroencephalographer is vital.

Efficacy of continuous midazolam infusion and mortality in childhood refractory generalized convulsive status epilepticus

PURPOSE

Continuous midazolam infusion is commonly used for the management of status epilepticus (SE). The purpose of this study was to assess the efficacy of midazolam and mortality in childhood refractory generalized convulsive SE.

METHODS

We included 27 children with refractory generalized convulsive SE. Midazolam was given 0.2 mg/kg as bolus, followed by 1-5 microg/kg/min as continuous infusion. Clinical data and response to treatment were recorded for each patient.

RESULTS

Acute symptomatic SE accounted for 52%, and central nervous system (CNS) infections were the most frequently associated etiologic condition (44%). Complete control of seizures was achieved with midazolam infusion in the 26 (96%) children within 65 min; at a mean midazolam infusion rate of 3.1 microg/kg/min. Adverse effects such as hypotension, bradycardia or respiratory depression did not occur during midazolam infusion. In one (4%) patient with acute meningoencephalitis, SE could not be controlled. Five (19%) patients died; four had acute symptomatic aetiology and one had progressive encephalopathy.

CONCLUSION

Midazolam is effective and safe in the control of refractory generalized convulsive SE. The response to treatment and mortality were related to the underlying aetiology.

Status epilepticus: clinical analysis of a treatment protocol based on midazolam and phenytoin

The efficacy of a combination of midazolam and phenytoin in treating generalized convulsive status epilepticus in children was studied retrospectively. The patient group comprised all patients admitted for generalized convulsive status epilepticus to the pediatric intensive care unit over 7 years. Patients treated according to the protocol were included (N = 122). These patients were treated with the following regimen; each subsequent step was taken if clinical evidence of epileptic activity persisted: midazolam 0.5 mg/kg rectally or 0.1 mg/kg intravenously. After 10 minutes: midazolam 0.1 mg/kg intravenously. After 10 minutes: phenytoin 20 mg/kg intravenously in 20 minutes. After phenytoin load: midazolam 0.2 mg/kg intravenously followed by midazolam 0.1 mg/kg/hour continuously, increased by 0.1 mg/kg/hour every 10 minutes to maximum 1 mg/kg/hour. Phenobarbital 20 mg/kg intravenously or pentobarbital 2 to 5 mg/kg intravenous load, 1 to 2 mg/kg/hour continuously intravenously. Patients who received initial rectal diazepam were included. Patients were categorized according to the cause of generalized convulsive status epilepticus. These categories were then related to the level of antiepileptic therapy needed. Patients' ages ranged from 0.5 to 197.4 months. The cause of generalized convulsive status epilepticus was idiopathic or febrile convulsions in two thirds of cases. Most (89%) patients were managed on midazolam and phenytoin. Generalized convulsive status epilepticus was terminated with midazolam alone in 58 patients, with the addition of phenytoin in 19 patients and with continuous midazolam in 32 patients. Thirteen patients needed additional barbiturates. The relationship between the level of antiepileptic therapy and etiology was not significant. Fifty-two patients needed artificial ventilation. Seven patients died; no deaths were directly attributable to generalized convulsive status epilepticus itself. With the use of the proposed protocol, combining midazolam and phenytoin, 89% of the cases of generalized convulsive status epilepticus could be successfully managed.

Management of seizures in critically ill patients

For many neurologists, seizures in critically ill patients represent a difficult problem. Etiology can be elusive because of the complexity of the environment, and treatment decisions can be compromised by the paucity of evidence-based guidelines. Emerging data support a higher than previously thought incidence of nonconvulsive epileptic activity in this patient population, which is another important consideration. Although a seizure in the intensive care unit should be treated aggressively, prophylactic antiepileptic drug administration is dependent on the specific etiology, time of onset, and ensuing complications. After ischemic stroke, prophylactic treatment is not generally recommended, and after intracerebral hemorrhage treatment is recommended only after a few weeks. After subarachnoid hemorrhage, prophylactic treatment beyond discharge is also not recommended. Although there is no reason to believe that late seizures after severe head trauma cannot be prevented with prophylactic treatment, such an approach may be useful during the first week after the injury. Physicians, however, have to individualize the treatment to the critical patient after stroke or trauma based on the presence of additional factors that increase the risk for seizures, including structural cortical injuries and medications used in critical illness with epileptogenic potential. A general therapeutic scheme for seizures in the intensive care unit and the role newer antiepileptic drugs can play are also presented in this review.

Comparative tolerability of sedative agents in head-injured adults

Sedative agents are widely used in the management of patients with head injury. These drugs can facilitate assisted ventilation and may provide useful reductions in cerebral oxygen demand. However, they may compromise cerebral oxygen delivery via their cardiovascular effects. In addition, individual sedative agents have specific and sometimes serious adverse effects. This review focuses on the different classes of sedative agents used in head injury, with a discussion of their role in the context of clinical pathophysiology. While there is no sedative that has all the desirable characteristics for an agent in this clinical setting, careful titration of dose, combination of agents, and a clear understanding of the pathophysiology and pharmacology of these agents will allow safe sedative administration in head injury.