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)

Myoclonus dystonia (M-D) is a hereditary movement disorder caused by a maternally imprinted gene that is often associated with psychiatric symptoms. Most cases of M-D are believed to result from mutations of the epsilon-sarcoglycan protein. The neuroanatomical distribution of epsilon-sarcoglycan-like immunoreactivity in mouse was investigated by using an antiserum against the epsilon-sarcoglycan protein. The expression of epsilon-sarcoglycan mRNA was studied by a sensitive fluorescence in situ hybridization (FISH) method. Immunohistochemistry and FISH revealed a wide distribution of epsilon-sarcoglycan protein and mRNA throughout the mouse brain. High expression levels of epsilon-sarcoglycan mRNA and immunoreactivity were found in the mitral cell layer of the olfactory bulb, the Purkinje cell layer in cerebellum, and the monoaminergic neurons in the mouse midbrain. Immunohistochemistry revealed a similar distribution of epsilon-sarcoglycan protein. Double-labeling FISH showed colocalization of tyrosine hydroxylase and epsilon-sarcoglycan mRNAs within all the midbrain dopaminergic (DAergic) cell groups. By combining FISH with fluorescence immunohistochemistry, coexpression of epsilon-sarcoglycan mRNA and tryptophan hydroxylase immunoreactivity was found in the serotonergic (5-HTergic) neurons within the dorsal raphe nucleus. The distribution of epsilon-sarcoglycan in the mouse brain suggests that the symptom complex of M-D may be related to the effects of decreased epsilon-sarcoglycan activity on the development or function of monoaminergic neurons.
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PMID:Epsilon-sarcoglycan immunoreactivity and mRNA expression in mouse brain. 1561 18

Negative myoclonus, commonly known as asterixis, is often observed in patients with toxic-metabolic encephalopathies or focal brain lesions. It is a movement disorder characterized by postural lapses resulting from brief cessation of tonic muscular contraction. Negative myoclonus has a characteristic appearance on needle electromyography. Lapses in continuous postural muscle activity can lead to falls. This increased risk of falls makes it particularly important to recognize and treat negative myoclonus, especially in patients with multiple medical problems, deconditioning, and gait disturbances. To our knowledge, there have been no published reports implicating negative myoclonus as a cause of falls in adults. We present a case of asterixis as a cause of falls and near falls in a patient with metastatic breast cancer and normal mental status who was receiving gabapentin.
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PMID:Asterixis related to gabapentin as a cause of falls. 1614 53

Tardive dyskinesia is a movement disorder that develops after exposure to dopamine receptor blocking agents. Less well-appreciated are other, more recently described tardive syndromes that are phenomenologically distinct from tardive dyskinesia and respond to different treatments. Patients may simultaneously have more than one tardive syndrome. Major subtypes of tardive syndromes include tardive dyskinesia, characterized by orobuccolingual, truncal, or appendicular, choreiform movements; tardive dystonia, characterized by sustained, stereotyped muscle spasms of a twisting or turning character; and tardive akathisia, characterized by an inner sense of restlessness or unease. The sensation often is unpleasant and may be accompanied by repetitive, purposeless movements (stereotypies), such as pacing. Less common tardive syndromes include tardive myoclonus, tardive tourettism, and tardive tremor. Tardive syndromes often are a source of great distress and disability to patients and may be permanent, despite discontinuing the responsible medication. Prevention, early detection, and prompt management are the major clinical focus. When a patient develops a tardive syndrome appropriate actions include 1) review of the primary diagnosis that prompted starting a dopamine receptor blocking agent; 2) characterization of the movement disorder(s); 3) where possible, discontinuation of dopamine blocking agent or replacement with a less potent alternative agent; 4) gradual withdrawl of the offending drug because some patients have an exacerbation of a tardive syndrome after abrupt withdrawal; and 5) assessment of the severity of symptoms and development of a treatment plan based on the phenomenology, with the goal of maximizing patient comfort and function. Although tardive dyskinesia typically develops after chronic exposure to dopamine receptor blocking agents, it, and other variants (such as tardive dystonia) can develop very rapidly after treatment. There seems to be no minimal safe duration of exposure for the development of a tardive syndrome. It is important to recognize that anti-emetics, which are dopamine receptor blockers, such as prochlorperazine, promethazine and metoclopramide, can cause tardive syndromes. Clinicians should become familiar with antipsychotic agents that have a lower risk of causing tardive syndromes, such as clozapine, quetiapine, and olanzapine. We review treatment options for tardive dystonia.
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PMID:Tardive Dystonia. 1581 76

Movement disorders (ataxia, dystonic disorders, gait disorders, Huntington disease, myoclonus, parkinsonism, spasticity, tardive dyskinesia, tics and tremor) are clinically, pathologically and genetically heterogeneous and are characterized by impairment of the planning, control or execution of movement. Current classifications of these disorders have inherent shortcomings due to the complex nature of movement disorders and the lack of diagnostic tests for the majority. Undiscriminating terminology, as well as the clinical, pathological and genetic heterogeneity, further complicate the development of comprehensive categorizations. Modern classification schemes tend to focus on clinical, pathological or genetic/molecular criteria, but more recent attempts have been made to integrate across these levels. From a historical perspective, two 'golden ages' have shaped the current and evolving classification schemes: (1) the definition of clinical pathological entities in the early twentieth century and (2) the application of molecular neurogenetics in the past 10-15 years. However, the classification of movement disorders on clinical grounds (according to age at onset, distribution of symptoms, disease course, provoking factors and therapeutic response) remains one of the most useful modes of categorization. Postmortem criteria have been employed to distinguish between degenerative and nondegenerative disorders, and specific hallmarks may be required to establish or confirm a diagnosis. Genetic features used for classification purposes include mode of inheritance and molecular genetic data, such as linkage to a known gene locus or identification of a specific genetic defect. A final classification scheme is based on alterations in molecular mechanisms (e.g. trinucleotide expansions) or protein function (e.g. channelopathies). Despite recent advances, it may not be possible to develop the 'ultimate' classification of movement disorders, and different patterns of lumping and splitting may be useful for the clinician, the pathologist or the geneticist/molecular biologist. Furthermore, certain individual cases with unique features may not fit into any particular category. Continued research by both clinicians and basic scientists is necessary in order to refine and redefine classification schemes of movement disorders.
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PMID:Movement disorders: classifications. 1586 75

Movement disorders and epilepsy rarely occur in the early stage of Creutzfeldt-Jakob disease (CJD) but have not been reported concurrently. We report on a 47-year-old patient with probable CJD who presented with generalized chorea and focal dystonia with myoclonic jerks on the right hand. Myoclonic jerks progressed to epilepsia partialis continua within 5 days of admission to the hospital. The diagnosis of our patient was compatible with probable CJD on the basis of clinical course, electroencephalogram, and diffusion-weighted magnetic resonance imaging findings, and presence of 14-3-3 protein in cerebrospinal fluid. To our knowledge, this is the first report of a case developing both movement disorders and epilepsia partialis continua in the early stage of the disease.
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PMID:Coexistence of movement disorders and epilepsia partialis continua as the initial signs in probable Creutzfeldt-Jakob disease. 1589 25

Propriospinal myoclonus is a rare form of spinal myoclonus. In most cases the cause has remained unclear. Secondary propriospinal myoclonus has been described secondary to various disorders including trauma, tumor, and infection. Thus far, propriospinal myoclonus caused by cervical disc herniation has not been reported. In the present report, the authors describe the case of a 53-year-old man who presented with radicular symptoms of the right C-6 nerve root and myoclonic twitches predominantly affecting the abdominal muscles but spreading to adjacent muscles. The spread was triggered and enforced by certain movements. Magnetic resonance imaging studies revealed a C-6 nerve root compression at the C5-6 level on the right side but no cervical myelopathy. Electromyography studies confirmed the diagnosis of propriospinal myoclonus. After discectomy and cage-augmented fusion via an anterior approach, the myoclonic movement disorder gradually subsided. To the authors' knowledge, this is the first report on successful treatment of propriospinal myoclonus by spinal disc surgery.
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PMID:Propriospinal myoclonus due to cervical disc herniation. Case report. 1594 38

We developed and tested the clinimetric properties of a scale for psychogenic movement disorders (PMDs). PMDs are disabling but lack any generally accepted treatment strategies. To develop treatments, means of assessing disease severity must be provided. No scale to assess PMDs existed. The PMD scale developed here rates 10 phenomena (rest tremor, action tremor, dystonia, chorea, bradykinesia, myoclonus, tics, athetosis, ballism, cerebellar incoordination), 2 functions (gait, speech), and 14 body regions. To study interrater agreement, three movement disorder neurologists independently rated 88 videotapes of PMD patients. Data analysis was performed using a kappa coefficient of agreement, Kendall's coefficient of concordance, Spearman correlations, and intraclass correlation coefficients. Validity and scale responsiveness were tested as well. All phenomena and speech and gait dysfunction occurred in the patient sample. A wide range of affected body regions, severity, and incapacitation was captured. Ratings showed excellent interrater reliability for presence or absence of each phenomenon (kappa range, 0.63 to 0.86). Kendall's concordance coefficients for phenomenology, function, and total PMD scores were 0.92, 0.93, and 0.91. Spearman correlations between raters ranged from 0.86 to 0.90. The scale was responsive to changes that occurred as a result of a neuropsychiatric intervention. The PMD scale adequately captures the complex movements of PMDs and can be used to assess PMDs and test the efficacy of intervention strategies.
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PMID:Rating scale for psychogenic movement disorders: scale development and clinimetric testing. 1610 25

Post-hypoxic myoclonus is a movement disorder characterized by brief, sudden involuntary muscle jerks. Although the mechanism underlying this disorder remains unclear, earlier pharmacological studies indicated that aberrant activity of specific neuronal circuitry in the central nervous system causes this disorder. In the present study, Fos protein, an immediate-early gene product, was used as a marker of neuronal activity to identify the brain nuclei possibly involved in post-hypoxic myoclonus. We found that Fos protein was immunologically detected in the reticular thalamic nucleus (RT), the medial longitudinal fasciculus (MLF) as well as in the locus coeruleus (LC) and the periventricular gray substance (PVG) in post-hypoxic rats that developed myoclonus in response to auditory stimuli. Fos was not detected in these nuclei from rats that underwent 4 min of cardiac arrest without myoclonus. Electrolytic lesions of the RT or MLF but not the LC/PVG significantly reduced auditory stimulated myoclonus in the post-hypoxic rats. The results suggest that neuronal activity in the RT and the MLF plays a contributing role in post-hypoxic myoclonus.
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PMID:Post-hypoxic myoclonus induces Fos expression in the reticular thalamic nucleus and neurons in the brainstem. 1619 30

Movement disorders are reported in a significant number of patients within the course of Creutzfeldt-Jakob disease (CJD). Although myoclonus is more frequent, dystonia, choreoathetosis, tremor, hemiballismus, and atypical parkinsonian syndromes have also been reported. In this review, we report the principal movement disorders associated with CJD and evaluate their correlations with neuroradiological and neuropathological findings that could in fact suggest a basal ganglia dysfunction. Further studies are warranted in order to clarify these correlations.
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PMID:Movement disorders and Creutzfeldt-Jakob disease: a review. 1636 74

Post-anoxic myoclonus is a rare movement disorder manifested by diffuse action-triggered jerking movements that may result in significant disability. The incidence of this disorder is not clearly established, but over 122 cases have so far been reported in the literature. The pathogenesis is not entirely known, although it has been hypothesized that particular susceptibility of the Purkinje cells of cerebellum to anoxic injury may play a key role. A case is presented of an independently living 60-year-old woman admitted to the rehabilitation unit with diffuse myoclonus after sustaining a cardio-pulmonary arrest. She presented with severe jerking movements in all extremities with startle to noise and exacerbations upon attempting any purposeful actions. The patient's myoclonus was controlled by a variety of anti-epileptic medications. The patient initially responded to a combination of divalproex sodium and zonisamide, but relapsed in several weeks, requiring addition of levetriacetam and clonazepam. At a 1-year follow-up she demonstrated a significant improvement in ambulation and self-care activities. This case illustrates that, although patients with post-anoxic myoclonus cannot be fully cured, their quality of life can be significantly improved by rehabilitation interventions.
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PMID:Post-anoxic myoclonus: a case presentation and review of management in the rehabilitation setting. 1642 Oct 70


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