CONTEXT: The optimal pharmacologic treatment for early convulsive status epilepticus is unclear. OBJECTIVE: To analyze efficacy, tolerability and safety data for anticonvulsant treatment of children and adults with convulsive status epilepticus and use this analysis to develop an evidence-based treatment algorithm. DATA SOURCES: Structured literature review using MEDLINE, Embase, Current Contents, and Cochrane library supplemented with article reference lists. STUDY SELECTION: Randomized controlled trials of anticonvulsant treatment for seizures lasting longer than 5 minutes. DATA EXTRACTION: Individual studies were rated using predefined criteria and these results were used to form recommendations, conclusions, and an evidence-based treatment algorithm. RESULTS: A total of 38 randomized controlled trials were identified, rated and contributed to the assessment. Only four trials were considered to have class I evidence of efficacy. Two studies were rated as class II and the remaining 32 were judged to have class III evidence. In adults with convulsive status epilepticus, intramuscular midazolam, intravenous lorazepam, intravenous diazepam and intravenous phenobarbital are established as efficacious as initial therapy (Level A). Intramuscular midazolam has superior effectiveness compared to intravenous lorazepam in adults with convulsive status epilepticus without established intravenous access (Level A). In children, intravenous lorazepam and intravenous diazepam are established as efficacious at stopping seizures lasting at least 5 minutes (Level A) while rectal diazepam, intramuscular midazolam, intranasal midazolam, and buccal midazolam are probably effective (Level B). No significant difference in effectiveness has been demonstrated between intravenous lorazepam and intravenous diazepam in adults or children with convulsive status epilepticus (Level A). Respiratory and cardiac symptoms are the most commonly encountered treatment-emergent adverse events associated with intravenous anticonvulsant drug administration in adults with convulsive status epilepticus (Level A). The rate of respiratory depression in patients with convulsive status epilepticus treated with benzodiazepines is lower than in patients with convul-
We report a study of 73 consecutive children with acute cerebellar ataxia, representing all of the children evaluated at St. Louis Children's Hospital during a 23-year-period to whom this diagnosis could appropriately be assigned. Twenty-six percent had chickenpox, 52% had other illnesses that were presumed to be viral, and in 3% the ataxia was related to immunization. Nineteen percent had no definite prodrome. Sixty children were followed for 4 months or longer after onset of their ataxia (mean, 7.4 +/- 6.0 years). Ninety-one percent (55/60) of these, including all children with chickenpox, recovered completely from ataxia. Eighty-nine percent (39/44) of the children with non-varicella-related ataxia recovered completely from the ataxia, a much better rate of recovery than what was found in prior large studies. One fifth of the children followed for more than 4 months experienced transient behavioral or intellectual difficulties, but only 5 of the 60 children demonstrated sustained learning problems. This study represents the largest reported series of acute cerebellar ataxia and the most complete characterization of the clinical features and outcome of this illness.
Topiramate is effective as monotherapy in adults and children. Because a therapeutic effect emerges during titration, clinicians should adjust dosages in step-wise fashion with intermediate stopping points, e.g., 100 mg/day, to evaluate patient response and achieve the optimal maintenance dosage.
Felbamate (FBM) is a new antiepileptic drug (AED) that has been evaluated in partial seizures and in the Lennox-Gastaut syndrome (LGS). When tested against placebo in an add-on, randomized, double-blind trial in 73 children with LGS, FBM significantly reduced the frequencies of astatic (atonic) seizures and generalized tonic-clonic seizures plus total seizure counts. In addition, FBM-treated subjects improved significantly on a parent-rated global evaluation and had fewer injuries. Overall, approximately 50% of subjects experienced a 50% or greater reduction in total seizure frequency and a dose-response relationship was apparent. The improvement that occurred in the double-blind study has been sustained for at least 12 months in subsequent open-label follow-up studies. In the first month of FBM treatment, 62% of the subjects who had previously received placebo had a reduction in total seizure frequency of > 50%. By the 12-month follow-up point, approximately half of the patients had a 50% reduction in total seizure count. Astatic seizures responded even better, with two-thirds of patients having a reduction of > 50% in astatic seizure frequency after 12 months of treatment. Based on adverse experience reports thus far, FBM appears to be well tolerated. FBM is the first drug to be shown effective in the LGS in randomized controlled trials. Although few subjects with LGS became seizure free, the frequency of the most severe seizure types decreased and the patients' global functioning improved.
Four unrelated children were thought to have valproate-associated hepatotoxicity. They presented with recurrent partial secondarily generalized status epilepticus and epilepsia partialis continua followed by mental and motor regression. Despite treatment with multiple antiepileptic medications, they continued to have seizures. After initiation of valproic acid (VPA), all 4 manifested liver failure within 3 months. Two of these children each had 1 sibling who was not exposed to VPA, but who developed the same clinical picture including liver failure. At the time of autopsy, all 6 children had similar neuropathological findings with focal areas of spongiosis and neuronal loss, diffuse gliosis, and Alzheimer type II cells. One VPA-treated patient underwent a successful liver transplantation only to die from relentlessly progressive neurological deterioration. We propose that many of the reported patients with VPA-associated hepatotoxicity represent undiagnosed patients with early childhood hepatocerebral degeneration, the Huttenlocher variant of Alpers' syndrome. This disease manifests by obstinate partial seizures, recurrent partial secondarily generalized status epilepticus, epilepsia partialis continua, psychomotor deterioration, and hepatic dysfunction that is exacerbated by VPA administration. The accelerated demise from liver failure in the nontransplanted patients before the central nervous system pathology fully evolves makes the diagnosis of this rare condition difficult. The occurrence of disease in the unexposed siblings suggests recessive inheritance.
While generic medications offer the potential for signifi c a n t cost reduction, s h o r t -t e r m economic considerations should not be allowed to jeopardize the health of persons with epilepsy. Doing so may actually increase health care costs in addition to adversely affecting quality of life. Concern exists that some generic antiepileptic medications provide insufficient biologic equivalence to the brand name product for which they are s~bstituted.'-~ Also, generic antiepileptic drugs may not adequately substitute for each other. These concerns are greatest for phenytoin and carbamazepine. Three pharmacologic factors are associated with risk for nonequivalence: low water solubility, narrow therapeutic range, and nonlinear pharmacokinetics. Phenytoin possesses these 3 risk factors, and carbamazepine possesses the 1st two.Despite such pharmacologic complexities, the testing required by the Food and Drug Administration (FDA) is similar to that required for most generic drugs that lack the problems associated with antiepileptic medication, such as antibiotics. Approval has been granted despite genericbrand name drug intrasubject availability ratios of 74-142% (see below). No account has been taken of many other factors relevant to actual clinical use of generics, such as capsule content and shelf life.Nonequivalence can have very serious effects. Decreased serum drug concentrations can cause breakthrough seizures, and increased concentrations can lead to toxicity. Breakthrough seizures in well-controlled patients with epilepsy can result in serious injury, and can injure or kill others if they occur during driving. Drug toxicity can lead to discomfort, injury, or poor job performance. The overall cost to society of breakthrough seizures or drug toxicity may outweigh any economic incentive for mandating generic substitution. The economic goal of cost containment by generic substitution is meaningless if it leads to increased morbidity and mortality. Any assessment of the effect of substitution must be based on interpretation of the relevant principles of pharmacology and clinical neurology as well as the relevant social and economic issues.Pharmacologic principles. Traditionally, the bioavailability of a generic drug is compared with that of a brand name drug by administering each drug to the same volunteers at different times. After each drug is administered, serum is collected over time, and a plot is made of serum concentration versus time (figure). From this plot, 3 pharmacokinetic values are calculated for each drug: (1) the area under the serum concentrationtime curve (AUC), (2) the maximum serum concentration after administration of the drug (C-), and (3) the time between administration of the drug and the attainment of maximum serum concentration (t-).The AUC is one of the principal pharmacokinetic values used in comparing bioavailability of different formulations of a drug. In single-dose studies, the AUC is a measure of both the total amount of drug absorbed (DA) and of the mean drug serum concentration...
Amygdalohippocampectomy (AH) is an accepted surgical option for treatment of medically refractory mesial temporal lobe epilepsy. Operative approaches to the amygdala and hippocampus that previously have been reported include: the sylvian fissure, the superior temporal sulcus, the middle temporal gyrus, and the fusiform gyrus. Regardless of the approach, AH permits not only extirpation of an epileptogenic focus in the amygdala and anterior hippocampus, but interruption of pathways of seizure spread via the entorhinal cortex and the parahippocampal gyrus. The authors report a modification of a surgical technique for AH via the parahippocampal gyrus, in which excision is limited to the anterior hippocampus, amygdala and parahippocampal gyrus while preserving the fusiform gyrus and the rest of the temporal lobe. Because transparahippocampal AH avoids injury to the fusiform gyrus and the lateral temporal lobe, it can be performed without intracarotid sodium amobarbital testing of language dominance and language mapping. Thus the operation would be particularly suitable for pediatric patients in whom intraoperative language mapping before resection is difficult.
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