Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027066 (myoclonus)
 4,275 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Valproic acid in therapeutic doses was used in the treatment of postanoxic intention myoclonus. Disappearance of the myoclonus occurred with marked improvement in the electroencephalogram. No significant side effects were noted. Hepatic function tests were monitored. Determination of valproic acid plasma levels was used to guide therapy. Levels above 55 micrograms were generally required. The patient remains free of myoclonus after four and one half months.
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PMID:Treatment of postanoxic intention myoclonus with valproic acid. 12 39

A total of 20 children with various types of epilepsy were treated with valproate, 11 with monotherapy and 9 with valproate in combination with phenobarbitone, phenytoin, or carbamazepine. Valproate was given either every 8 or 12 h. At least two different dose levels were tried in each patient. The pharmacokinetics of valproate during the interval between doses was determined using a gas chromatographic technique. The clinical effect of the treatment was assessed by interviewing the parents. The plasma concentrations showed considerable fluctuation during the intervals between doses. The mean increase from pre-administration to peak level was 82% when the dose interval was 12 h, and 62% when it was 8 h. The mean plasma half-life of valproate, using a one-compartment model, was 10.9 +/- 1.3 h (mean +/- SD). The plasma half-life of valproate was decreased when the drug was combined with the other anti-epileptics. The calculated area under the concentration versus time curve was linearly related to dose, both in a single patient on four dose levels and when different patients were compared. The clinical effect of valproate monotherapy was best in patients with absences, usually good in myoclonus and less favourable in other types of epilepsy. For children with absences, the optimal dose range of valproate was between 20 and 40 mg/kg/24 h. In comparison, the myoclonic types of epilepsy needed a slightly higher dose level, between 30 and 60 mg/kg/24 h. In the latter group a "therapeutic window" seems to exist, since patients below and above the suggested dose levels were not well-controlled. Therapeutic monitoring of valproate does not appear meaningful when the drug is used as monotherapy. However, in combination therapy, determination of the plasma levels of all anti-convulsants used may be helpful. The large fluctuations of valproate during a dose interval must be taken into consideration when the clinical effects are analysed.
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PMID:Plasma concentrations of valproate during maintenance therapy in epileptic children. 618 49

Twelve patients with benign juvenile myoclonic epilepsy (BJME) representing 4% of our population of epileptics (n = 275) are presented. Only two patients (17%) had myoclonic jerks as the only seizure type. Seven (58%) had generalized tonic-clonic seizures (GTCS) and myoclonus. Three patients (25%) had absence seizures (AS), GTCS, and myoclonic jerks. Electroencephalographic evidence of photosensitivity was found in four (33%). Auditory precipitation of seizures was found in one patient. As is the case with other primary generalized epilepsies, the onset of BJME seems to be age specific. In our series the mean age of onset in years was 4.3 for AS, 14.75 for myoclonic jerks, and 16.4 for GTCS. It took an average of 8.5 years from the onset of BJME (range, 2-20 years) and 6.5 years from the onset of GTCS (range, 2 months-6 years) until the condition was properly recognized. Five patients experienced at least one episode of myoclonic status epilepticus. Generalized, paroxysmal, symmetric polyspike and slow wave discharges are the typical EEG finding. These complexes, however, showed considerable interpatient variability. Sleep deprivation proved to be the most valuable activating procedure. Valproic acid monotherapy effectively controlled myoclonic jerks as well as associated GTCS in most patients.
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PMID:Some clinical and EEG aspects of benign juvenile myoclonic epilepsy. 642 Jan 45

We present the first documented case of photic-induced epileptic negative myoclonus. A 17-year-old girl had experienced two generalized tonic-clonic seizures (GTCS) while watching television. The only EEG abnormality was a photoparoxysmal response (PPR), which was sometimes accompanied by loss of postural tone in both arms. Valproate was effective in abolishing photosensitivity. Negative myoclonus should be included among the ictal phenomena accompanying PPR.
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PMID:Photic-induced epileptic negative myoclonus: a case report. 861 79

Clinical and electroencephalographic data and response to drug therapy of 3 boys and 3 girls aged 14-19 years, mean 16, with juvenile myoclonic epilepsy (JME) are described. All presented with violent myoclonic jerks upon awakening, prompted by sleep deprivation and precipitated by deliberate awakening. Following onset of myoclonic jerks, generalized tonic-clonic seizures (GCTS) and absences occurred after 6-18 months (mean 11). The EEG revealed normal background activity in all, along with generalized epileptiform activity in the form of 3-4 Hz polyspike/slow wave or spike/slow wave, commonly induced by hyperventilation. Valproic acid (VPA), 12 mg/kg/day (range 10-15), resulted in complete and rapid cessation of myoclonic jerks, of absences and recurrent GTCS. Discontinuation of VPA resulted in recurrence of myoclonic jerks and then GTCS, but were completely controlled by reinstitution of VPA. All have remained asymptomatic on VPA, with cognition preserved, during a follow-up of up to 6 years. JME is a unique, benign, epileptic syndrome easily and rapidly controlled by rather small doses of valproic acid given on a long-term basis. Myoclonic jerks may serve as a reliable indicator of JME and therefore should be screened for in any case of unprovoked generalized seizures. The smallness of the doses of the drug used suggests that the dose prescribed should be "syndrome" related rather than weight related, as is usually prescribed in children.
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PMID:[Juvenile myoclonic epilepsy--an underdiagnosed epileptic syndrome]. 898 99

Based on small numbers of patients, it is possible to make the following suggestions rather than categorical statements. For myoclonic seizures and epilepsies which are not otherwise specified, valproate seems of proven efficacy. Ethosuximide may be a useful adjunct. The exact place of lamotrigine, which controls some myoclonia and makes them worse in other patients, requires further study. The findings are clearer when specific syndromes are considered. Valproate is the treatment of first choice for benign myoclonic epilepsy in infants, myoclonic astatic epilepsy, epilepsy with myoclonic absences, eyelid myoclonia with absences, juvenile myoclonic epilepsy and progressive myoclonus epilepsy. The addition of ethosuximide to valproate can be helpful to those with myoclonic absences, where this combination appears more beneficial than either valproate or ethosuximide alone and in eyelid myoclonia with absences. Lamotrigine can be effective therapy for juvenile myoclonic epilepsy and eyelid myoclonia with absences when used alone and, in conjunction with other antiepileptic drugs (AED) (usually valproate) for early myoclonic encephalopathy, myoclonic-astatic epilepsy and particularly, epilepsy with myoclonic absences. The myoclonia of infantile neuronal ceroid lipofuscinosis respond to lamotrigine. Severe myoclonic epilepsy of infants usually worsens with lamotrigine, but occasionally, children improve. Zonisamide added to clonazepam and valproate or a barbiturate, can reduce the cascade of myoclonia in progressive myoclonus epilepsies for at least 2 years, but relapse may occur thereafter.
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PMID:Myoclonus and epilepsy in childhood: a review of treatment with valproate, ethosuximide, lamotrigine and zonisamide. 947 47

A 7-year-old female with benign childhood epilepsy with centrotemporal spikes developed epileptic negative myoclonus (ENM) seizures during carbamazepine (CBZ) treatment. She had experienced nocturnal partial seizures since 5 years of age. Interictal electroencephalography demonstrated typical rolandic discharges. Valproate was first initiated at 6 years of age, but the seizures were uncontrollable. Carbamazepine was added and valproate withdrawn. The frequency of partial seizures did not decrease. Moreover, she had brief episodes of tone loss in each or both arms and eye blinking several weeks after CBZ introduction. Unilateral loss of arm tone corresponded to spike-and-wave discharges in the contralateral centrotemporal region, and a loss of tone in arms was associated with bilateral synchronous discharges. Eye blinking was also related to bilateral synchronous discharges and classified as a myoclonic seizure. The ENM and myoclonic seizures disappeared soon after CBZ withdrawal. Therefore the authors concluded that CBZ induced the ENM and myoclonic seizures in this patient. CBZ sometimes induces generalized seizures in the treatment of partial epilepsy and generalized epilepsy. CBZ-induced ENM seizures should be considered when a brief lapse of tone appears during CBZ treatment.
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PMID:Epileptic negative myoclonus induced by carbamazepine in a child with BECTS. Benign childhood epilepsy with centrotemporal spikes. 1051 96

Fourteen patients with juvenile myoclonic epilepsy (JME) were treated with a single low dose of a sustained-release preparation of sodium valproate (VPA, 500 mg daily). The mean age of the onset of the low dose treatment was 19.2 years (range 14-26). Before this treatment, six patients had been treated with high dose VPA for a period of more than 2 years, three patients for 1 to 2 years, three patients less than 1 year and two patients initiated the treatment from the beginning with a low dose. The mean duration of low dose treatment is 35.6 months (range 25-59 months). (All patients are still under medication). Generalized tonic-clonic and absence seizures were controlled in all patients. Myoclonic jerks relapsed only in one patient, a young mother who was looking after her newly born baby and was deprived of sleep. No adverse reactions have been reported. We suggest that JME patients can effectively be treated with single low VPA dose (500 mg daily), while at the same time seizure precipitating factors, such as sleep deprivation and alcohol ingestion, should be avoided.
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PMID:Low dose sodium valproate in the treatment of juvenile myoclonic epilepsy. 1196 42

It is estimated that Angelman syndrome (AS) accounts for up to 6% of all children presenting with severe mental retardation and epilepsy. The main clinical features of AS may not be apparent early in life. Clinical findings present in all patients include developmental delay, which becomes apparent by 6-12 months of age, severely impaired expressive language, ataxic gait, tremulousness of limbs, and a typical behavioral profile, including a happy demeanor, hypermotoric behavior, and low attention span. Seizures, abnormal electroencephalography, microcephaly, and scoliosis are observed in >80% of patients. Approximately 70% of patients show a deletion involving the maternally inherited chromosome 15q11-q13, encompassing a cluster of gamma-aminobutyric acid receptor subunit genes, 3% show chromosome 15 paternal uniparental disomy (UPD), 1% harbor a mutation in the imprinting center (a transcriptional regulatory element), and 6% harbor intragenic mutations of the ubiquitin-protein ligase E3A (UBE3A) gene. Twenty percent of patients have no detectable genetic abnormality. Rare cases of familial recurrence of AS show either imprinting center (IC) or UBE3A mutations. Approximately 75% of cases are detected through the methylation test, which allows the detection of AS due to deletions, UPD and IC mutations. Mutation analysis of the UBE3A gene should be performed when the methylation test is negative. Individuals with chromosome 15q11-q13 deletions have a more severe clinical picture and are more prone to develop severe epilepsy. Epilepsy has typical features, including absence and myoclonic seizures, and insidious episodes of nonconvulsive or subtle myoclonic status which are easily overlooked as children appear apathetic or in a state of neurologic regression. Tremulousness, present in all patients even when seizures are well controlled or absent, is related to distal cortical myoclonus. Valproic acid (sodium valproate), benzodiazepines, and ethosuximide, in various combinations, are quite effective in treating the typical seizure types. Piracetam may help in reducing distal myoclonus. Carbamazepine and vigabatrin may seriously aggravate absence and myoclonic seizures and should be avoided. Cognitive, language, and orthopedic problems must be addressed with vigorous rehabilitation programs, including early physical therapy, which may help to develop communicative skills and prevent severe scoliosis and subsequent immobility. Where these treatment strategies are applied, individuals with AS may reach an appreciable level of integration, self care, and have a normal life span.
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PMID:Angelman syndrome: etiology, clinical features, diagnosis, and management of symptoms. 1451 Jun 23

The scientific and medical history of valproic acid is relatively long, compared with other frequently used psychopharmacologic agents. Valproic acid was used as an organic solvent in research laboratories for eight decades, until the fortuitous observation of action against pentylenetetrazol-induced convulsions in rodents. Early clinical experience emphasized therapy of absence seizures in primary generalized epilepsies. During two decades of controlled trials in partial-onset and generalized-onset seizures and myoclonus, valproate was established as the prototypical broad-spectrum antiepileptic drug. Anecdotal observations in patients with both epilepsy and migraine headaches who were started on valproate led to prospective, randomized trials that established antimigraine efficacy. Early observations suggested antimanic actions; more than a decade later, controlled clinical trials established significant efficacy of valproate in mania. Antiproliferative effects of valproate were unexpectedly noted during mechanistic studies; two decades later a maintenance adjunctive or chemopreventive role in oncology is being defined. While pharmacokinetic studies appear definitive, completion of comprehensive pharmacodynamic investigations of valproate's biochemical actions and clinical utility is yet to be achieved.
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PMID:The history of valproate in clinical neuroscience. 1462 29


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