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Avoli M, de Curtis M, Lévesque M, Librizzi L, Uva L, Wang S. GABAA signaling, focal epileptiform synchronization and epileptogenesis. Front Neural Circuits 2022; 16:984802. [PMID: 36275847 PMCID: PMC9581276 DOI: 10.3389/fncir.2022.984802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 09/13/2022] [Indexed: 12/04/2022] Open
Abstract
Under physiological conditions, neuronal network synchronization leads to different oscillatory EEG patterns that are associated with specific behavioral and cognitive functions. Excessive synchronization can, however, lead to focal or generalized epileptiform activities. It is indeed well established that in both epileptic patients and animal models, focal epileptiform EEG patterns are characterized by interictal and ictal (seizure) discharges. Over the last three decades, employing in vitro and in vivo recording techniques, several experimental studies have firmly identified a paradoxical role of GABAA signaling in generating interictal discharges, and in initiating—and perhaps sustaining—focal seizures. Here, we will review these experiments and we will extend our appraisal to evidence suggesting that GABAA signaling may also contribute to epileptogenesis, i.e., the development of plastic changes in brain excitability that leads to the chronic epileptic condition. Overall, we anticipate that this information should provide the rationale for developing new specific pharmacological treatments for patients presenting with focal epileptic disorders such as mesial temporal lobe epilepsy (MTLE).
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Affiliation(s)
- Massimo Avoli
- Montreal Neurological Institute-Hospital, Montreal, QC, Canada
- Departments of Neurology and Neurosurgery, Montreal, QC, Canada
- Department of Physiology, McGill University, Montreal, QC, Canada
- *Correspondence: Massimo Avoli,
| | - Marco de Curtis
- Epilepsy Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Istituto Neurologico Carlo Besta, Milan, Italy
| | - Maxime Lévesque
- Montreal Neurological Institute-Hospital, Montreal, QC, Canada
- Departments of Neurology and Neurosurgery, Montreal, QC, Canada
| | - Laura Librizzi
- Epilepsy Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Istituto Neurologico Carlo Besta, Milan, Italy
| | - Laura Uva
- Epilepsy Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Istituto Neurologico Carlo Besta, Milan, Italy
| | - Siyan Wang
- Montreal Neurological Institute-Hospital, Montreal, QC, Canada
- Departments of Neurology and Neurosurgery, Montreal, QC, Canada
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Cherubini E, Di Cristo G, Avoli M. Dysregulation of GABAergic Signaling in Neurodevelomental Disorders: Targeting Cation-Chloride Co-transporters to Re-establish a Proper E/I Balance. Front Cell Neurosci 2022; 15:813441. [PMID: 35069119 PMCID: PMC8766311 DOI: 10.3389/fncel.2021.813441] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 11/30/2021] [Indexed: 01/01/2023] Open
Abstract
The construction of the brain relies on a series of well-defined genetically and experience- or activity -dependent mechanisms which allow to adapt to the external environment. Disruption of these processes leads to neurological and psychiatric disorders, which in many cases are manifest already early in postnatal life. GABA, the main inhibitory neurotransmitter in the adult brain is one of the major players in the early assembly and formation of neuronal circuits. In the prenatal and immediate postnatal period GABA, acting on GABAA receptors, depolarizes and excites targeted cells via an outwardly directed flux of chloride. In this way it activates NMDA receptors and voltage-dependent calcium channels contributing, through intracellular calcium rise, to shape neuronal activity and to establish, through the formation of new synapses and elimination of others, adult neuronal circuits. The direction of GABAA-mediated neurotransmission (depolarizing or hyperpolarizing) depends on the intracellular levels of chloride [Cl−]i, which in turn are maintained by the activity of the cation-chloride importer and exporter KCC2 and NKCC1, respectively. Thus, the premature hyperpolarizing action of GABA or its persistent depolarizing effect beyond the postnatal period, leads to behavioral deficits associated with morphological alterations and an excitatory (E)/inhibitory (I) imbalance in selective brain areas. The aim of this review is to summarize recent data concerning the functional role of GABAergic transmission in building up and refining neuronal circuits early in development and its dysfunction in neurodevelopmental disorders such as Autism Spectrum Disorders (ASDs), schizophrenia and epilepsy. In particular, we focus on novel information concerning the mechanisms by which alterations in cation-chloride co-transporters (CCC) generate behavioral and cognitive impairment in these diseases. We discuss also the possibility to re-establish a proper GABAA-mediated neurotransmission and excitatory (E)/inhibitory (I) balance within selective brain areas acting on CCC.
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Affiliation(s)
- Enrico Cherubini
- European Brain Research Institute (EBRI)-Rita Levi-Montalcini, Roma, Italy
- *Correspondence: Enrico Cherubini
| | - Graziella Di Cristo
- Neurosciences Department, Université de Montréal and CHU Sainte-Justine Research Center, Montreal, QC, Canada
| | - Massimo Avoli
- Montreal Neurological Institute-Hospital and Departments of Neurology and Neurosurgery and of Physiology, McGill University, Montreal, QC, Canada
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3
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Charalambous M, Volk HA, Van Ham L, Bhatti SFM. First-line management of canine status epilepticus at home and in hospital-opportunities and limitations of the various administration routes of benzodiazepines. BMC Vet Res 2021; 17:103. [PMID: 33663513 PMCID: PMC7934266 DOI: 10.1186/s12917-021-02805-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 02/16/2021] [Indexed: 12/22/2022] Open
Affiliation(s)
- Marios Charalambous
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, 9820, Merelbeke, Belgium.
| | - Holger A Volk
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, 30559, Hannover, Germany
| | - Luc Van Ham
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, 9820, Merelbeke, Belgium
| | - Sofie F M Bhatti
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, 9820, Merelbeke, Belgium
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Lévesque M, Ragsdale D, Avoli M. Evolving Mechanistic Concepts of Epileptiform Synchronization and their Relevance in Curing Focal Epileptic Disorders. Curr Neuropharmacol 2020; 17:830-842. [PMID: 30479217 PMCID: PMC7052840 DOI: 10.2174/1570159x17666181127124803] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 10/26/2018] [Accepted: 11/17/2018] [Indexed: 01/01/2023] Open
Abstract
The synchronized activity of neuronal networks under physiological conditions is mirrored by specific oscillatory patterns of the EEG that are associated with different behavioral states and cognitive functions. Excessive synchronization can, however, lead to focal epileptiform activity characterized by interictal and ictal discharges in epileptic patients and animal models. This review focusses on studies that have addressed epileptiform synchronization in temporal lobe regions by employing in vitro and in vivo recording techniques. First, we consider the role of ionotropic and metabotropic excitatory glutamatergic transmission in seizure generation as well as the paradoxical role of GABAA signaling in initiating and perhaps maintaining focal seizure activity. Second, we address non-synaptic mechanisms (which include voltage-gated ionic currents and gap junctions) in the generation of epileptiform synchronization. For each mechanism, we discuss the actions of antiepileptic drugs that are presumably modulating excitatory or inhibitory signaling and voltage-gated currents to prevent seizures in epileptic patients. These findings provide insights into the mechanisms of seizure initiation and maintenance, thus leading to the development of specific pharmacological treatments for focal epileptic disorders.
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Affiliation(s)
- Maxime Lévesque
- Montreal Neurological Institute, McGill University, Montreal, H3A 2B4 Quebec, Canada
| | - David Ragsdale
- Montreal Neurological Institute, McGill University, Montreal, H3A 2B4 Quebec, Canada
| | - Massimo Avoli
- Montreal Neurological Institute, McGill University, Montreal, H3A 2B4 Quebec, Canada.,Departments of Neurology & Neurosurgery, and of Physiology, McGill University, Montréal, H3A 2B4 Québec, Canada.,Department of Experimental Medicine, Facoltà di Medicina e Odontoiatria, Sapienza University of Rome, 00185 Roma, Italy
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Warraich S, Ali A, Nizami A, Bakhiet M. Can endotracheal intubation be the first step in management of nonconvulsive status epilepticus?: A case report. Medicine (Baltimore) 2018; 97:e9950. [PMID: 29443785 PMCID: PMC5839821 DOI: 10.1097/md.0000000000009950] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
RATIONALE Nonconvulsive status epilepticus (NCSE) is prolonged seizure activity without motor manifestations. Clinically, there are certain examination findings, in addition to elements of history, that help differentiate it from other encephalopathies. When diagnosing NCSE, the physician faces significant difficulties due to inconsistent clinical presentation and somewhat nonspecific electroencephalogram (EEG) criteria. PATIENT CONCERNS To highlight the problems faced when dealing with such a patient, a case of a 29-year-old male who presented with an altered state of consciousness is put forth for the reader. Only after an extensive laboratory and radiological workup had ruled out other causes, an eventual diagnosis was established when clinical features were correlated with suggestive EEG results. DIAGNOSES The diagnosis that was reached was NCSE. INTERVENTIONS The initial therapeutic interventions generally deployed in such a scenario ultimately failed and consequently the patient had to be sedated and intubated, while being kept on antiepileptic medication. OUTCOMES This measure resulted in satisfactory recovery. LESSONS Accordingly, we recommend consideration of NCSE in any unconscious patient whose presentation cannot be explained by other disorders. Furthermore, we suggest moving directly to utilizing anesthetic agents and endotracheal intubation, together with anti-epileptic drugs, in the treatment regimen in order to optimize patient outcomes.
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Affiliation(s)
| | - Abbas Ali
- King Hamad University Hospital, Al Sayh
| | | | - Moiz Bakhiet
- King Hamad University Hospital, Al Sayh
- Department of Molecular Medicine, College of Medicine and Medical Science, Arabian Gulf University, Manama
- Princess Al-Jawhara Center for Molecular Medicine, Genetics and Inherited Disorders, Manama, Kingdom of Bahrain
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Kämppi L, Mustonen H, Kotisaari K, Soinila S. The essence of the first 2.5 h in the treatment of generalized convulsive status epilepticus. Seizure 2018; 55:9-16. [DOI: 10.1016/j.seizure.2017.12.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 12/20/2017] [Accepted: 12/27/2017] [Indexed: 12/29/2022] Open
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Kapoor M, Cloyd JC, Siegel RA. A review of intranasal formulations for the treatment of seizure emergencies. J Control Release 2016; 237:147-59. [PMID: 27397490 DOI: 10.1016/j.jconrel.2016.07.001] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 06/30/2016] [Accepted: 07/01/2016] [Indexed: 12/20/2022]
Abstract
Epileptic seizure emergencies are life-threatening conditions, which in their most severe form, status epilepticus, have a high mortality rate if not quickly terminated. Treatment requires rapid delivery of anti-epileptics such as benzodiazepines to the brain. The nasal route is attractive due to its non-invasiveness, potential for direct nose to brain delivery, high vascularity, relatively large absorptive surface area, and avoidance of intestinal/liver metabolism. However, the limited volume of the nasal cavity and poor water solubility of anti-epileptics restrict absorption, leading to insufficient therapeutic brain levels. This review covers various formulation approaches adopted to improve nasal delivery of drugs, especially benzodiazepines, used to treat seizure emergencies. Other general topics such as nasal anatomy, challenges to nasal delivery, and drug/formulation considerations for nose to brain delivery are also discussed.
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Affiliation(s)
- Mamta Kapoor
- Department of Pharmaceutics, University of Minnesota, Minneapolis, MN, USA
| | - James C Cloyd
- Department of Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, MN, USA; Department of Neurology, University of Minnesota, Minneapolis, MN, USA
| | - Ronald A Siegel
- Department of Pharmaceutics, University of Minnesota, Minneapolis, MN, USA; Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA.
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Kapoor M, Cheryala N, Rautiola D, Georg GI, Cloyd JC, Siegel RA. Chirally Pure Prodrugs and Their Converting Enzymes Lead to High Supersaturation and Rapid Transcellular Permeation of Benzodiazepines. J Pharm Sci 2016; 105:2365-71. [PMID: 27342435 DOI: 10.1016/j.xphs.2016.05.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Revised: 05/05/2016] [Accepted: 05/09/2016] [Indexed: 11/29/2022]
Abstract
Water-soluble prodrugs can be rapidly converted by enzymes to hydrophobic drugs, whose aqueous thermodynamic solubilities are low, but are maintained in aqueous solution at supersaturated concentrations due to slow precipitation kinetics. Recently, we investigated avizafone (AVF) in combination with Aspergillus oryzae protease as a prodrug/enzyme system intended to produce supersaturated diazepam (DZP). Several fold enhancement of permeation of supersaturated DZP across Madin-Darby canine kidney II-wild type (MDCKII-wt) monolayers was observed, compared to saturated DZP solutions. However, prodrug conversion was incomplete, putatively due to partial racemization of AVF and stereoselectivity of A oryzae protease. Here we report synthesis of chirally pure AVF, and demonstrate complete conversion to supersaturated DZP followed by complete DZP permeation at enhanced rates across MDCKII-wt cell monolayers. We also synthesized, for the first time, a chirally pure prodrug of midazolam (MDZ-pro) and carried out the same sequence of studies. A oryzae protease was identified as a benign and efficient activating enzyme for MDZ-pro. The MDZ-pro/A oryzae protease system showed greater than 25-fold increase in absorption rate of MDZ across MDCKII-wt monolayers, compared to saturated MDZ. Such chirally pure prodrug/enzyme systems are promising candidates for efficient intranasal delivery of benzodiazepine drugs used in the treatment of seizure emergencies.
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Affiliation(s)
- Mamta Kapoor
- Department of Pharmaceutics, University of Minnesota, Minneapolis, Minnesota 55414
| | - Narsihmulu Cheryala
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55414; Institute for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, Minnesota 55414
| | - Davin Rautiola
- Department of Pharmaceutics, University of Minnesota, Minneapolis, Minnesota 55414
| | - Gunda I Georg
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55414; Institute for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, Minnesota 55414
| | - James C Cloyd
- Department of Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, Minnesota 55414; Center for Orphan Drug Research, University of Minnesota, Minneapolis, Minnesota 55414
| | - Ronald A Siegel
- Department of Pharmaceutics, University of Minnesota, Minneapolis, Minnesota 55414; Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55414.
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Abstract
OBJECTIVE Medical coma is an anesthetic-induced state of brain inactivation, manifest in the electroencephalogram by burst suppression. Feedback control can be used to regulate burst suppression, however, previous designs have not been robust. Robust control design is critical under real-world operating conditions, subject to substantial pharmacokinetic and pharmacodynamic parameter uncertainty and unpredictable external disturbances. We sought to develop a robust closed-loop anesthesia delivery (CLAD) system to control medical coma. APPROACH We developed a robust CLAD system to control the burst suppression probability (BSP). We developed a novel BSP tracking algorithm based on realistic models of propofol pharmacokinetics and pharmacodynamics. We also developed a practical method for estimating patient-specific pharmacodynamics parameters. Finally, we synthesized a robust proportional integral controller. Using a factorial design spanning patient age, mass, height, and gender, we tested whether the system performed within clinically acceptable limits. Throughout all experiments we subjected the system to disturbances, simulating treatment of refractory status epilepticus in a real-world intensive care unit environment. MAIN RESULTS In 5400 simulations, CLAD behavior remained within specifications. Transient behavior after a step in target BSP from 0.2 to 0.8 exhibited a rise time (the median (min, max)) of 1.4 [1.1, 1.9] min; settling time, 7.8 [4.2, 9.0] min; and percent overshoot of 9.6 [2.3, 10.8]%. Under steady state conditions the CLAD system exhibited a median error of 0.1 [-0.5, 0.9]%; inaccuracy of 1.8 [0.9, 3.4]%; oscillation index of 1.8 [0.9, 3.4]%; and maximum instantaneous propofol dose of 4.3 [2.1, 10.5] mg kg(-1). The maximum hourly propofol dose was 4.3 [2.1, 10.3] mg kg(-1) h(-1). Performance fell within clinically acceptable limits for all measures. SIGNIFICANCE A CLAD system designed using robust control theory achieves clinically acceptable performance in the presence of realistic unmodeled disturbances and in spite of realistic model uncertainty, while maintaining infusion rates within acceptable safety limits.
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Affiliation(s)
- M Brandon Westover
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Seong-Eun Kim
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - ShiNung Ching
- Department of Electrical and Systems Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Patrick L Purdon
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Emery N Brown
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
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Muraja-Murro A, Mervaala E, Westeren-Punnonen S, Lepola P, Töyräs J, Myllymaa S, Julkunen P, Kantanen AM, Kälviäinen R, Myllymaa K. Forehead EEG electrode set versus full-head scalp EEG in 100 patients with altered mental state. Epilepsy Behav 2015; 49:245-9. [PMID: 25997637 DOI: 10.1016/j.yebeh.2015.04.041] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 04/19/2015] [Indexed: 11/17/2022]
Abstract
BACKGROUND Acute EEG is vastly underutilized in acute neurological settings. The most common reason for this is simply the fact that acute EEG is not available when needed or getting EEG is delayed as it requires trained technicians and equipment to be properly recorded. We have recently described a handy disposable forehead EEG electrode set that is suitable for acute emergency EEG recordings. The specific objective in this study was to assess the forehead electrode's utility when the clinical demand was to exclude SE. PATIENTS AND METHODS One hundred consecutive acute neurological patients (53 women, 47 men, age: 18-90 years) with unexplained altered mental state were studied with acute emergency EEG to rule out SE. Electroencephalographic recordings were obtained simultaneously with forehead EEG electrode and routine 10-20 system full-head scalp electrodes to clarify the clinical usefulness of forehead EEG electrode in this setting. Electroencephalographic recordings were interpreted blindly by three experienced clinical neurophysiologists first only based on forehead EEG and then by full-head EEG. RESULTS Ninety-six out of the 100 patients did not show EEG evidence of SE. There was 100% agreement with forehead and routine EEG. Four out of the 100 patients showed EEG evidence of SE in routine EEG, with 50% agreement between different electrode types. The forehead EEG missed two cases because the EEG findings supporting SE were restricted to the posterior parts of the brain. MAJOR CONCLUSIONS With a forehead EEG set, the sensitivity of detecting NCSE was 50%. There were no false positive cases yielding a specificity of 100%. Patients with AMS can benefit from forehead EEG recording in prehospital, hospital, and ICU settings. Since EEG recording can be started within a few minutes with the forehead EEG set, it will significantly reduce the delay in treatment of SE. This article is part of a Special Issue entitled "Status Epilepticus".
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Affiliation(s)
- Anu Muraja-Murro
- Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland; School of Medicine, University of Eastern Finland, Kuopio, Finland.
| | - Esa Mervaala
- Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland; School of Medicine, University of Eastern Finland, Kuopio, Finland
| | - Susanna Westeren-Punnonen
- Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland; School of Medicine, University of Eastern Finland, Kuopio, Finland
| | - Pasi Lepola
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Juha Töyräs
- Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland; Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Sami Myllymaa
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Petro Julkunen
- Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland; Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Anne-Mari Kantanen
- Department of Neurology, Kuopio University Hospital, Kuopio, Finland; School of Medicine, University of Eastern Finland, Kuopio, Finland
| | - Reetta Kälviäinen
- Department of Neurology, Kuopio University Hospital, Kuopio, Finland; School of Medicine, University of Eastern Finland, Kuopio, Finland
| | - Katja Myllymaa
- Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland; Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
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Siegel RA, Kapoor M, Cheryala N, Georg GI, Cloyd JC. Water-soluble benzodiazepine prodrug/enzyme combinations for intranasal rescue therapies. Epilepsy Behav 2015; 49:347-50. [PMID: 26115606 DOI: 10.1016/j.yebeh.2015.05.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2015] [Accepted: 05/01/2015] [Indexed: 10/23/2022]
Abstract
Benzodiazepines (BZDs), including diazepam (DZP) and midazolam (MDZ), are drugs of choice for rapid treatment of seizure emergencies. Current approved use of these drugs involves administration via either intravenous or rectal routes. The former requires trained medical personnel, while the latter is socially unacceptable for many patients and caregivers. In recent years, efforts have been made to formulate BZDs for nasal administration. Because of the low solubility of these molecules, organic vehicles have been used to solubilize the drugs in the nasal products under development. However, organic solvents are irritating, potentially resulting in injury to nasal tissue. Here we report preliminary studies supporting a strategy in which water-soluble BZD prodrugs and a suitable converting enzyme are coadministered in an aqueous vehicle. Diazepam and midazolam prodrugs were synthesized and were readily converted to their active forms by a protease from Aspergillus oryzae. Using a permeation assay based on monolayers of Madin-Darby canine kidney II-wild type cells, we found that enzymatically produced BZDs could be maintained at high degrees of supersaturation, enabling faster transport across the membrane than can be achieved using saturated solutions. This strategy not only obviates the need for organic solvents, but it also suggests more rapid absorption and earlier peak concentrations than can be otherwise achieved. This article is part of a Special Issue entitled "Status Epilepticus".
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Affiliation(s)
- Ronald A Siegel
- Department of Pharmaceutics, University of Minnesota, Minneapolis, MN 55455, USA; Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Mamta Kapoor
- Department of Pharmaceutics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Narsihmulu Cheryala
- Department of Medicinal Chemistry and Institute for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, MN 55414, USA; Institute for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Gunda I Georg
- Department of Medicinal Chemistry and Institute for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, MN 55414, USA; Institute for Therapeutics Discovery and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - James C Cloyd
- Department of Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA; Center for Orphan Drug Research, University of Minnesota, Minneapolis, MN 55455, USA.
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Kapoor M, Winter T, Lis L, Georg GI, Siegel RA. Rapid delivery of diazepam from supersaturated solutions prepared using prodrug/enzyme mixtures: toward intranasal treatment of seizure emergencies. AAPS JOURNAL 2014; 16:577-85. [PMID: 24700272 DOI: 10.1208/s12248-014-9596-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 03/20/2014] [Indexed: 11/30/2022]
Abstract
Current treatments for seizure emergencies, such as status epilepticus, include intravenous or rectal administration of benzodiazepines. While intranasal delivery of these drugs is desirable, the small volume of the nasal cavity and low drug solubility pose significant difficulties. Here, we prepared supersaturated diazepam solutions under physiological conditions and without precipitation, using a prodrug/enzyme system. Avizafone, a peptide prodrug of diazepam, was delivered with--Aspergillus oryzae (A.O.) protease, an enzyme identified from a pool of hydrolytic enzymes in assay buffer, pH 7.4 at 32°C. This enzyme converted avizafone to diazepam at supersaturated concentrations. In vitro permeability studies were performed at various prodrug/enzyme ratios using Madin-Darby canine kidney II-wild type (MDCKII-wt) monolayers, a representative model of the nasal epithelium. Monolayer integrity was examined using TEER measurement and the lucifer yellow permeability assay. Prodrug/drug concentrations were measured using HPLC. Enzyme kinetics with avizafone-protease mixtures revealed K(M) = 1,501 ± 232 μM and V(max) = 1,369 ± 94 μM/s. Prodrug-protease mixtures, when co-delivered apically onto MDCKII-wt monolayers, showed 2-17.6-fold greater diazepam flux (S = 1.3-15.3) compared to near-saturated diazepam (S = 0.7). Data for prodrug conversion upstream (apical side) and drug permeability downstream (basolateral side) fitted reasonably well to a previously developed in vitro two compartment pharmacokinetic model. Avizafone-protease mixtures resulted in supersaturated diazepam in less than 5 min, with the rate and extent of supersaturation determined by the prodrug/enzyme ratio. Together, these results suggest that an intranasal avizafone-protease system may provide a rapid and alternative means of diazepam delivery.
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Affiliation(s)
- Mamta Kapoor
- Department of Pharmaceutics, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota, 55455, USA
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Chapman CD, Frey WH, Craft S, Danielyan L, Hallschmid M, Schiöth HB, Benedict C. Intranasal treatment of central nervous system dysfunction in humans. Pharm Res 2012; 30:2475-84. [PMID: 23135822 PMCID: PMC3761088 DOI: 10.1007/s11095-012-0915-1] [Citation(s) in RCA: 204] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 10/12/2012] [Indexed: 01/30/2023]
Abstract
One of the most challenging problems facing modern medicine is how to deliver a given drug to a specific target at the exclusion of other regions. For example, a variety of compounds have beneficial effects within the central nervous system (CNS), but unwanted side effects in the periphery. For such compounds, traditional oral or intravenous drug delivery fails to provide benefit without cost. However, intranasal delivery is emerging as a noninvasive option for delivering drugs to the CNS with minimal peripheral exposure. Additionally, this method facilitates the delivery of large and/or charged therapeutics, which fail to effectively cross the blood-brain barrier (BBB). Thus, for a variety of growth factors, hormones, neuropeptides and therapeutics including insulin, oxytocin, orexin, and even stem cells, intranasal delivery is emerging as an efficient method of administration, and represents a promising therapeutic strategy for the treatment of diseases with CNS involvement, such as obesity, Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, depression, anxiety, autism spectrum disorders, seizures, drug addiction, eating disorders, and stroke.
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Affiliation(s)
- Colin D Chapman
- Department of Neuroscience, Uppsala University, Box 593, Husargatan 3, Uppsala, Sweden.
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Abstract
PURPOSE OF REVIEW Acute ischemic stroke (AIS) can have profound and devastating effects on the CNS and several other organs. Approximately 15% to 20% of patients with AIS are admitted to an intensive care unit and cared for by a multidisciplinary team. This article discusses the critical care management of patients with AIS. RECENT FINDINGS Patients with AIS require attention to airway, pulmonary status, blood pressure, glucose, temperature, cardiac function, and, sometimes, life-threatening cerebral edema. SUMMARY The lack of disease-specific data has led to numerous management approaches and limited guidance on choosing among them. Existing guidelines emphasize risk factors, prevention, natural history, and prevention of bleeding but provide little discussion of the complex critical care issues involved in caring for patients with AIS.
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Affiliation(s)
- William M Coplin
- Wayne State University, Department of Neurology, 4201 St. Antoine-8C, Detroit, MI 48201, USA.
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17
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Wermeling DP. Intranasal delivery of antiepileptic medications for treatment of seizures. Neurotherapeutics 2009; 6:352-8. [PMID: 19332330 PMCID: PMC5084214 DOI: 10.1016/j.nurt.2009.01.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 01/12/2009] [Accepted: 01/13/2009] [Indexed: 11/15/2022] Open
Abstract
Acute isolated seizure, repetitive or recurrent seizures, and status epilepticus are all deemed medical emergencies. Mortality and worse neurologic outcome are directly associated with the duration of seizure activity. A number of recent reviews have described consensus statements regarding the pharmacologic treatment protocols for seizures when patients are in pre-hospital, institutional, and home-bound settings. Benzodiazepines, such as lorazepam, diazepam, midazolam, and clonazepam are considered to be medications of first choice. The rapidity by which a medication can be delivered to the systemic circulation and then to the brain plays a significant role in reducing the time needed to treat seizures and reduce opportunity for damage to the CNS. Speed of delivery, particularly outside of the hospital, is enhanced when transmucosal routes of delivery are used in place of an intravenous injection. Intranasal transmucosal delivery of benzodiazepines is useful in reducing time to drug administration and cessation of seizures in the pre-hospital setting, when actively seizing patients arrive in the emergency room, and at home where caregivers treat their dependents. This review summarizes factors to consider when choosing a benzodiazepine for intranasal administration, including formulation and device considerations, pharmacology and pharmacokinetic/pharmacodynamic profiles. A review of the most relevant clinical studies in epilepsy patients will provide context for the relative success of this technique with a number of benzodiazepines and relatively less sophisticated nasal preparations. Neuropeptides delivered intranasally, crossing the blood-brain barrier via the olfactory system, may increase the availability of medications for treatment of epilepsy. Consequently, there remains a significant unmet medical need to serve the pharamcotherapeutic requirements of epilepsy patients through commercial development and marketing of intranasal antiepileptic products.
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Affiliation(s)
- Daniel P Wermeling
- Department of Pharmacy Practice and Science, University of Kentucky College of Pharmacy, Lexington, Kentucky 40536-0082, USA.
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McDonough JH, Van Shura KE, LaMont JC, McMonagle JD, Shih TM. Comparison of the Intramuscular, Intranasal or Sublingual Routes of Midazolam Administration for the Control of Soman-Induced Seizures*. Basic Clin Pharmacol Toxicol 2009; 104:27-34. [DOI: 10.1111/j.1742-7843.2008.00326.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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A pharmacokinetic and pharmacodynamic study, in healthy volunteers, of a rapidly absorbed intranasal midazolam formulation. Epilepsy Res 2008; 83:124-32. [PMID: 19046855 DOI: 10.1016/j.eplepsyres.2008.10.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Revised: 10/02/2008] [Accepted: 10/17/2008] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare 2.5 mg and 5.0 mg single-dose pharmacokinetics (PK), pharmacodynamics (PD) and tolerability of an intranasal (i.n.) midazolam formulation, to a 2.5-mg intravenous (i.v.) dose. METHODS Design was an open-label, three-way crossover, randomized PK and PD study in seventeen healthy volunteers. Twelve-hour PK parameters were determined for each treatment arm. Subjects completed serial self-ratings for sedation and other drug effects. Nurse observers made serial observations for sedation and adverse effects. An otolaryngologist conducted a nasal endoscopy, pre-dose, 2-4 h, and at end of study, to examine the nasal cavity for formulation-induced changes in nasal anatomy. RESULTS Midazolam was rapidly absorbed following i.n. administration, with a median t(max) of 10 min; dose proportionate increases for C(max) and AUC; t(1/2) of 4 h; and, 60% (+/-23) nasal administration bioavailability compared to the i.v. dose. PD responses were rapid, paralleled the PK, and in magnitude was in a rank order of i.v. 2.5 mg > or = i.n. 5.0 mg > i.n. 2.5 mg doses. The formulation was well tolerated with no serious cardiovascular or respiratory complications. Fourteen subjects complained of at least one of the following: a brief and mild to moderate intensity facial flushing, nasal passage burning, sore throat or bad taste after drug administration. There were no adverse findings from the nasal endoscopic exam. CONCLUSION Dosages of an investigational i.n. midazolam formulation resulted in rapid absorption and attained plasma concentrations that correlated with pharmacodynamic effects.
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Miller JL, Ashford JW, Archer SM, Rudy AC, Wermeling DP. Comparison of Intranasal Administration of Haloperidol with Intravenous and Intramuscular Administration: A Pilot Pharmacokinetic Study. Pharmacotherapy 2008; 28:875-82. [DOI: 10.1592/phco.28.7.875] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Updates in the Management of Seizures and Status Epilepticus in Critically Ill Patients. Neurol Clin 2008; 26:385-408, viii. [DOI: 10.1016/j.ncl.2008.03.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Jordan KG, Hirsch LJ. In nonconvulsive status epilepticus (NCSE), treat to burst-suppression: pro and con. Epilepsia 2007; 47 Suppl 1:41-5. [PMID: 17044825 DOI: 10.1111/j.1528-1167.2006.00659.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dr. Jordan (PRO) argues that when refractory NCSE is combined with acute brain injury, it produces synergistically compounded brain damage that is time dependent. Treating to EEG burst-suppression is the most rapid and effective method for stopping NCSE. The risks of burst-suppression are common to many intensive care interventions and can be minimized with expert management. Dr. Hirsch (CON) argues that treating with coma-inducing medication is highly risky and has a high mortality rate, often due to iatrogenic complications. It remains unclear if nonconvulsive seizures cause permanent neuronal injury. Nonconvulsive seizures should be diagnosed and treated as quickly as possible,but with non-coma-inducing treatments in most cases [corrected]
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Affiliation(s)
- Kenneth G Jordan
- Jordan NeuroScience, Inc., San Bernardino, California 92404, USA.
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Abou Khaled KJ, Hirsch LJ. Advances in the management of seizures and status epilepticus in critically ill patients. Crit Care Clin 2007; 22:637-59; abstract viii. [PMID: 17239748 DOI: 10.1016/j.ccc.2006.06.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Seizures and status epilepticus are common in critically ill patients. They can be difficult to recognize because most are non-convulsive and require electroencephalogram monitoring to detect; hence, they are currently underdiagnosed. Early recognition and treatment are essential to obtain maximal response to first-line treatment and to prevent neurologic and systemic sequelae. Anti-seizure medication should be combined with management of the underlying cause and reversal of factors that can lower the seizure threshold, including many medications, fever, hypoxia, and metabolic imbalances. This article discusses specific treatments and specific situations, such as hepatic and renal failure patients and organ transplant patients.
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Affiliation(s)
- Karine J Abou Khaled
- Comprehensive Epilepsy Center, Department of Neurology, Columbia University Neurological Institute, New York, NY 10032, USA
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Abstract
Generalised convulsive status epilepticus is one of the most common emergencies encountered in clinical practice. This review discusses the recent understanding of this life-threatening condition with reference to the definition, pathophysiology, evaluation, complications, refractory status and prognosis. Besides epilepsy, other neurological and medical illnesses could be associated with status epilepticus. The goals of management and pharmacological approach are outlined, considering the available evidence. Prompt recognition and timely intervention, including pre-hospital treatment, are therapeutically beneficial. Refractory status should be managed in intensive care units under close monitoring. More evidence is needed for evolving the optimal treatment. A suitable treatment protocol would guide in avoiding the pitfalls at various points along the management pathway.
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Affiliation(s)
- R Nandhagopal
- Department of Neurology, Sri Venkateswara Institute of Medical Sciences, Tirupati 517507, Andhra Pradesh, India.
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Koenig SA, Buesing D, Longin E, Oehring R, Häussermann P, Kluger G, Lindmayer F, Hanusch R, Degen I, Kuhn H, Samii K, Jungck A, Brückner R, Seitz R, Boxtermann W, Weber Y, Knapp R, Richard HH, Weidner B, Kasper JM, Haensch CA, Fitzek S, Hartmann M, Borusiak P, Müller-Deile A, Degenhardt V, Korenke GC, Hoppen T, Specht U, Gerstner T. Valproic Acid-induced Hepatopathy: Nine New Fatalities in Germany from 1994 to 2003. Epilepsia 2006; 47:2027-31. [PMID: 17201699 DOI: 10.1111/j.1528-1167.2006.00846.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE Valproic acid (VPA) is an antiepileptic drug (AED) commonly used for generalized and focal epilepsies. We provide an update on hepatotoxic side effects in Germany between 1994 and 2003. METHODS We mailed a questionnaire to all members of the German Section of the International League Against Epilepsy, asking for VPA-induced side effects, especially severe side effects such as hepatopathy. RESULTS As a result of our questionnaire, we found 31 cases of reversible hepatotoxicity and nine cases of lethal hepatopathies in Germany from 1994 to 2003. CONCLUSIONS The outcome of patients with severe hepatotoxicity is better than that in the past. The risk of a VPA-induced hepatopathy is not limited to patients younger than 2 years, receiving polytherapy, or patients with congenital or acquired metabolic diseases.
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Affiliation(s)
- Stephan A Koenig
- University Children's Hospital Mannheim, Neuropediatric Unit, Mannheim, Germany.
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Wolfe TR, Macfarlane TC. Intranasal midazolam therapy for pediatric status epilepticus. Am J Emerg Med 2006; 24:343-6. [PMID: 16635708 DOI: 10.1016/j.ajem.2005.11.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2005] [Accepted: 11/07/2005] [Indexed: 11/30/2022] Open
Abstract
Prolonged seizure activity in a child is a frightening experience for families as well as care providers. Because duration of seizure activity impacts morbidity and mortality, effective methods for seizure control should be instituted as soon as possible, preferably at home. Unfortunately, parenteral methods of medication delivery are not available to most caregivers and rectal diazepam, the most commonly used home therapy, is expensive and often ineffective. This brief review article examines recent research suggesting that there is a better way to treat pediatric seizures in situations where no intravenous access is immediately available. Intranasal midazolam, which delivers antiepileptic medication directly to the blood and cerebrospinal fluid via the nasal mucosa, is safe, inexpensive, easy to learn by parents and paramedics, and provides better seizure control than rectal diazepam.
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Affiliation(s)
- Timothy R Wolfe
- Department of Emergency Medicine, Jordan Valley Hospital, West Jordan, UT 84088, USA.
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Abstract
PURPOSE OF REVIEW Status epilepticus is the most common neurologic emergency in children. The understanding of its less recognizable forms, its pharmacologic management, the role of electroencephalography and the long-term morbidity and mortality as a result of status epilepticus are consistently evolving. This review frames the current understanding of several issues as they apply to acute management in the emergency department. RECENT FINDINGS Researchers are working to define less recognizable forms of status epilepticus such as nonconvulsive, autonomic and psychogenic. Buccal and intranasal forms of midazolam are emerging as suitable alternatives to rectal diazepam in the initial treatment of status epilepticus. Valproic acid, chloral hydrate and newer-generation antiepileptics are being proposed as safe and effective alternatives to the traditional drugs used to treat status epilepticus. The role of electroencephalography in diagnosis is being elucidated. Risk factors for neurologic sequelae and mortality after status epilepticus remain an area of research with conflicting findings and no real consensus. SUMMARY The understanding of different types of status epilepticus, the options for pharmacologic treatment, the tools for diagnosis and the morbidity and mortality of the disease are still evolving. As a result, several areas for further research remain that will help clinicians in their approach to this complex condition.
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Affiliation(s)
- David M Walker
- Division of Emergency Medicine, Children's National Medical Center, and George Washington University School of Medicine and Health Sciences, Washington, District of Columbia 20010, USA.
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