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)

An 11-year-old girl with nonketotic hyperglycinemia who typically presented with a picture of early myoclonic encephalopathy in the neonatal period is presented in this article. Treated early with sodium benzoate and dextromethorphan, she became seizure-free, while myoclonus persisted. During examination, multifocal rhythmic myoclonic jerks in gamma frequency enhanced by motor activity were noted. Coherence analysis of the electroencephalography-electromyography relationship indicated a cortical origin of the myoclonic jerks. Observation of this case suggests that rhythmic cortical myoclonus may represent a late evolution of this rare disorder.
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PMID:High-frequency rhythmic cortical myoclonus in a long-surviving patient with nonketotic hypergylcemia. 1818 48

Unverricht-Lundborg disease (ULD), progressive myoclonic epilepsy type 1 (EPM1, OMIM254800), is an autosomal recessively inherited neurodegenerative disorder characterized by age of onset from 6 to 16 years, stimulus-sensitive myoclonus, and tonic-clonic epileptic seizures. Some years after the onset ataxia, incoordination, intentional tremor, and dysarthria develop. Individuals with EPM1 are mentally alert but show emotional lability, depression, and mild decline in intellectual performance over time. The diagnosis of EPM1 can be confirmed by identifying disease-causing mutations in a cysteine protease inhibitor cystatin B (CSTB) gene. Symptomatic pharmacologic and rehabilitative management, including psychosocial support, are the mainstay of EPM1 patients' care. Valproic acid, the first drug of choice, diminishes myoclonus and the frequency of generalized seizures. Clonazepam and high-dose piracetam are used to treat myoclonus, whereas levetiracetam seems to be effective for both myoclonus and generalized seizures. There are a number of agents that aggravate clinical course of EPM1 such as phenytoin aggravating the associated neurologic symptoms or even accelerating cerebellar degeneration. Sodium channel blockers (carbamazepine, oxcarbazepine) and GABAergic drugs (tiagabine, vigabatrin) as well as gabapentin and pregabalin may aggravate myoclonus and myoclonic seizures. EPM1 patients need lifelong clinical follow-up, including evaluation of the drug-treatment and comprehensive rehabilitation.
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PMID:Clinical picture of EPM1-Unverricht-Lundborg disease. 1832 13

We report here on a Japanese family in which five members in three generations developed non-progressive adult onset cortical tremor and epilepsy. Other than tremulous movements resembling essential tremor, the neurologic findings were unremarkable. Electrophysiologic studies revealed giant somatosensory evoked potentials (SEPs), enhanced long latency reflexes (C-reflex), and positive premovement cortical potentials, recorded by jerk-locked averaging, indicating cortical reflex myoclonus. The seizures were sporadic in nature and easily controlled by the anticonvulsants. The tremor also responded well to anticonvulsants such as clonazepam or sodium valproate, but not to beta-blockers. This dominantly inherited disorder should be considered in the differential diagnosis of essential tremor.
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PMID:Familial cortical tremor with epilepsy. 1859 Oct 60

A 77-years-old woman was admitted to our hospital due to uncontrolled myoclonus and generalized seizure. Since the age of 17, she has been suffering from myoclonic jerks and partial convulsions in her right arm. Administration of several unknown anticonvulsants had not alleviated her condition. She was able to spend her life without a handicap, except for the symptoms described above. She has been experiencing psychological stress since the age of 50, which has resulted in worsening of her symptoms, and she was prescribed phenytoin, carbamazepine, and phenobarbital, which were also ineffective. When a generalized convulsive attack occurs, she shows rapid muscle twitches in her right arm and her consciousness is clear. She also has cerebellar ataxia in her extremities. Brain magnetic resonance imaging (MRI) showed obvious cerebellar atrophy, and an electroencephalogram revealed a diffuse spike and wave complexes. A surface electromyogram (EMG) confirmed myoclonus in both arms. We diagnosed her as having juvenile myoclonus epilepsy and initiated sodium valproate monotherapy, which relieved the symptoms. The observed cerebellar ataxia might be due to long-term administration of phenytoin. When a neurologist encounters an intractable seizure without loss of consciousness, surface EMG is useful for diagnosing this treatable disease.
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PMID:[Case of juvenile myoclonic epilepsy misdiagnosed as simple partial seizure for more than 60 years]. 1917 10

Posthypoxic myoclonus is a rare and devastating complication of near-fatal cardiopulmonary arrest. Despite treatment with available anti-myoclonic agents, some patients may recover cognitively but remain completely disabled by severe myoclonus. We report a 16-year-old patient with severe treatment-refractory posthypoxic myoclonus, which improved markedly with administration of the drug sodium oxybate.
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PMID:A patient with intractable posthypoxic myoclonus (Lance-Adams syndrome) treated with sodium oxybate. 1940 May

We present a case of accidental injection of tranexamic acid instead of bupivacaine during spinal anesthesia. One minute after intrathecal injection of 3.5 mL of solution, the patient developed myoclonus of his lower extremities. Accidental intrathecal injection of the wrong drug was suspected and a used ampule of tranexamic acid discovered in the trash can. The ampules of tranexamic acid (500 mg/5 mL) and bupivacaine (5 mg/mL, Merck, Darmstadt, Germany) were similar in appearance. General anesthesia was induced. Ten hours later, the patient developed myoclonus of his upper extremities and face. His polymyoclonus was successfully treated with phenytoin, sodium thiopental infusion, sodium valproate and supportive care of the hemodynamic, and respiratory systems. The patient's condition progressively improved to full recovery.
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PMID:Polymyoclonus seizure resulting from accidental injection of tranexamic acid in spinal anesthesia. 1944 37

We report a 2-year-old girl who had repeated febrile or afebrile seizures since infancy. Prolonged left/right hemiconvulsions and myoclonus of the eyelids/extremities with generalization to tonic-clonic seizures, were refractory to antiepileptic agents. At age 1 year and 4 months, she contracted rotavirus infection, and developed status epilepticus with persistent right hemiclonic seizures. Left unilateral brain edema with subsequent emergence of cortical laminar necrosis and white matter lesions, and progressive atrophy of the left cerebral hemisphere were noted during this period. She showed residual right hemiparesis and mild intellectual disability, and had generalized/eyelid myoclonia and hot water epilepsy after a 5-month seizure-free period. Analysis for SCN1A, the gene encoding the neuronal voltage-gated Na+ channel alpha1 subunit revealed a nonsense mutation, R1892X. These indicate the potential risk in patients with severe myoclonic epilepsy in infancy (SMEI) to develop hemiconvulsion-hemiplegia (HH) syndrome. SCN1A mutations may need to be further explored in patients with HH syndrome without features of SMEI.
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PMID:Hemiconvulsion-hemiplegia syndrome in a patient with severe myoclonic epilepsy in infancy. 1956 49

We report a 17-year-old female patient with Lance-Adams syndrome caused by anoxic encephalopathy during a severe attack of bronchial asthma. She had difficulty in writing because of action myoclonus in her arms. She also exhibited freezing gait and was unable to walk without cane. Although her gait disturbance resembled those seen in patients with parkinsonism secondary to anoxic encephalopathy, surface electromyography revealed that it was caused by action myoclonus in her legs. The presence of giant somatosensory evoked potentials and enhanced cortical reflexes in response to the electrical stimulation to her posterior tibial nerves supported our diagnosis. A combined therapy with valproate sodium, clonazepam and piracetam (15 g/day) was not effective. However, her freezing gait remarkably improved and she was able to walk without help, after the treatment with sufficient dose of piracetam (21 g/day). Cortical hyperexcitability as revealed by electrophysiological examination also improved. We concluded that the combined therapy with antiepileptic drugs and piracetam was effective in the treatment for action myoclonus. However, because the effects seemed dose-related, the dosage of piracetam needed to be increased until the optimum effects were obtained.
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PMID:[Effects of piracetam therapy in a case of Lance-Adams syndrome]. 1976 56

A 56-year-old man with rheumatoid arthritis developed emotional lability and myoclonic seizure in the left arm, followed by fever and generalized convulsion. Brain magnetic resonance imaging (MRI) revealed leptomeningeal lesions with abnormal enhancement. MRI lesions were localized predominantly in the right cerebral subarachnoid spaces. Electroencephalogram showed epileptogenic focus at the right frontal and central points. After administration of valproate sodium improved convulsion and myoclonus, single photon emission computed tomography (SPECT) using N-isopropyl-p-(123)I-iodoamphetamine was performed. Brain SPECT displayed hypoperfusion predominantly in the right cerebral hemisphere. Cerebrospinal fluid (CSF) disclosed mild pleocytosis and marked elevations of interleukin-6 levels. Repeated CSF analyses showed cytology of class I and negative results for infectious pathogens. Methylprednisolone pulse therapy (1 g for 3 days, iv) and subsequent prednisolone administration (daily 50 mg, po) ameliorated neurological symptoms dramatically. Prednisolone was tapered to 20 mg/day for 5 months. Leptomeningeal MRI lesions were attenuated gradually followed by restoration of cerebral hypoperfusion on SPECT. He was diagnosed as rheumatoid leptomeningitis (RLM). Although clinical features of RLM exhibited variable deficits of the central nervous system (CNS), MRI failed to detect the corresponding CNS lesions. We first highlighted neuroradiological changes of cerebral hypoperfusion and leptomeningeal lesions in RLM. These neuroimages of our patient supported that leptomeningeal inflammation and the adjacent cerebrocortical ischemia could cause encephalitis-like symptoms in RLM patients.
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PMID:Rheumatoid leptomeningitis: radiological alteration of cerebral hypoperfusion and subarachnoid lesions. 2082 56

Myoclonus can be classified as physiologic, essential, epileptic, and symptomatic. Animal models of myoclonus include DDT and posthypoxic myoclonus in the rat. 5-Hydrotryptophan, clonazepam, and valproic acid suppress myoclonus induced by posthypoxia. The diagnostic evaluation of myoclonus is complex and involves an extensive work-up including basic electrolytes, glucose, renal and hepatic function tests, paraneoplastic antibodies, drug and toxicology screens, thyroid antibody and function studies, neurophysiology testing, imaging, and tests for malabsorption disorders, assays for enzyme deficiencies, tissue biopsy, copper studies, alpha-fetoprotein, cytogenetic analysis, radiosensitivity DNA synthesis, genetic testing for inherited disorders, and mitochondrial function studies. Treatment of myoclonus is targeted to the underlying disorder. If myoclonus physiology cannot be demonstrated, treatment should be aimed at the common pattern of symptoms. If the diagnosis is not known, treatment could be directed empirically at cortical myoclonus as the most common physiology. In cortical myoclonus, the most effective drugs are sodium valproic acid, clonazepam, levetiracetam, and piracetam. For cortical-subcortical myoclonus, valproic acid is the drug of choice. Here, lamotrigine can be used either alone or in combination with valproic acid. Ethosuximide, levetiracetam, or zonisamide can also be used as adjunct therapy with valproic acid. A ketogenic diet can be considered if everything else fails. Subcortical-nonsegmental myoclonus may respond to clonazepam and deep-brain stimulation. Rituximab, adrenocorticotropic hormone, high-dose dexamethasone pulse, or plasmapheresis have been reported to improve opsoclonus myoclonus syndrome. Reticular reflex myoclonus can be treated with clonazepam, diazepam and 5-hydrotryptophan. For palatal myoclonus, a variety of drugs have been used.
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PMID:Myoclonus. 2149 98


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