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)

A combination of clozapine and lithium can be used in the treatment of refractory schizophrenia, schizoaffective disorder and bipolar disorder with rapid cycling. We report a patient with refractory bipolar disorder who developed side-effects after combination therapy with clozapine and lithium at usual therapeutic dosages. Reversible neurotoxicity developed twice during the therapeutic course, once with the restarting of lithium, the other with increasing the dose of lithium, despite the lithium concentrations being less than 0.5 mEq/l. Neurotoxicity manifested as ataxia, coarse tremor, myoclonus, facial spasm and increased deep tendon reflex. While the mechanism causing toxicity is not clear, interaction between the serotonergic effect of clozapine and lithium may be the cause. This report is evidence that a combination of clozapine and lithium may increase the risk of neurotoxicity. We suggest the need to keep clozapine and lithium at lower dosages and closely monitor their side-effects as necessary when these drugs are used concomitantly.
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PMID:Reversible neurotoxicity induced by a combination of clozapine and lithium: a case report. 1022 8

Rigidity in the setting of continuous motor unit activity at rest can be caused by a variety of central and peripheral conditions. A central origin is suggested by the presence of painful reflex spasms. Focal spinal lesions and infective causes are relatively easily excluded through imaging, microbiological and serological studies. There then remain a group of patients who may have the classical 'stiff-man syndrome' or a related syndrome. When strict diagnostic criteria are used, patients with the stiff man syndrome uniformly have axial rigidity, and about 90% are found to have antibodies against glutamic acid decarboxylase. Treatment response and prognosis are excellent. Stiff persons with 'plus' signs, particularly those with rigidity of a distal limb, are unlikely to have the classical stiff man syndrome. They have a poorer treatment response and prognosis. Some have a paraneoplastic aetiology, while a non-malignant autoimmune basis seems likely in others. Those in whom post-mortem pathology findings are available usually are seen to have had an encephalomyelitis with prominent involvement of the grey matter. Clinically, stiff persons with 'plus' signs may be divided into three groups according to the aggressiveness of the pathology and its relative distribution. Encephalomyelitis with rigidity follows a relentless subacute course, leading to death within 3 years. Chronic cases may present with predominantly brainstem involvement, including generalised myoclonus (the 'jerking stiff person syndrome') or spinal cord involvement, dominated by stiffness and spasm in one or more limbs (the 'stiff limb syndrome').
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PMID:The stiff man and stiff man plus syndromes. 1046 Apr 39

Dystonia is an interesting disorder characterized by involuntary movement of the body part or parts leading to abnormal deformed postures. The usual signs and symptoms are local pain, spasm and abnormal movements. Sensory trick is an important clinical phenomenon and is characteristic of dystonia. It is usually separated from other movement disorders such as chorea, athetosis, tics and myoclonus clinically. Various non-dystonic conditions simulate dystonia and need to be separated in view of different line of management. Improved understanding in molecular biology has helped in understanding of the disease. Confusing neuropathology and neurochemistry have deterred the finding of an effective drug, however empirical use of few drugs have improved the gloomy situation. Few conditions such as dopa-responsive dystonia have definite treatment. Recently use of botulinum toxin has provided beneficial response in hyper muscular contraction states such as dystonia and spasticity, Surgery and other non-medical therapies are effective in few situations.
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PMID:A spectrum of dystonias-clinical features and update on management. 1127 44

Myoclonus, defined as shock-like involuntary movement, may be physiological or caused by a very wide variety of hereditary and acquired conditions. Because myoclonus can originate from different disorders and lesions affecting quite varied levels of the central and peripheral nervous systems, it represents from many points of view a diagnostic challenge. Moreover, new entities have been recently individualized, such as cortical tremor, which deserve renewed attention. The aim of this review is to propose a rationale for a diagnostic approach based on clinical and electrophysiological grounds. In this setting, we successively address 1) the clinical features allowing a positive diagnosis of myoclonus; 2) the clinical clues to the etiology; 3) the relevance of the clinical context to the diagnosis; and 4) the contribution of neurophysiology. Differentiating myoclonus from tics, spasm, chorea and dystonia can be difficult, and a careful reappraisal of clinical features allowing precise identification is presented. Moreover, the topographical distribution of myoclonus, the temporal pattern of muscle recruitment, the condition of occurrence and the rhythm of the event, may provide clinical clues relevant to the diagnosis. Myoclonus without associated epilepsy, myoclonus with epilepsy, myoclonus with encephalopathy, parkinsonism and/or dementia represent overlapping clinical categories, although they remain useful for the diagnostic approach. Using electrophysiology (including back-averaging EEG, MEG, SEP, C-reflex studies) to determine the origin of myoclonus may not allow us to focus on the underlying condition. Indeed, in many instances, the myoclonus is cortical in origin, but the pathology is found elsewhere.
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PMID:[Myoclonus in the adult: diagnostic approach]. 1128 Oct 67

Hyperekplexia (startle disease) is a rare non-epileptic disorder characterised by an exaggerated persistent startle reaction to unexpected auditory, somatosensory and visual stimuli, generalised muscular rigidity, and nocturnal myoclonus. The genetic basis is a mutation usually of the arginine residue 271 leading to neuronal hyperexcitability by impairing glycinergic inhibition. Hyperekplexia is usually familial, most often autosomal dominant with complete penetrance and variable expression. It can present in fetal life as abnormal intrauterine movements, or later at any time from the neonatal period to adulthood. Early manifestations include abnormal responses to unexpected auditory, visual, and somatosensory stimuli such as sustained tonic spasm, exaggerated startle response, and fetal posture with clenched fists and anxious stare. The tonic spasms may mimic generalised tonic seizures, leading to apnoea and death. Consistent generalised flexor spasm in response to tapping of the nasal bridge (without habituation) is the clinical hallmark of hyperekplexia. Electroencephalography may show fast spikes initially during the tonic spasms, followed by slowing of background activity with eventual flattening corresponding to the phase of apnoea bradycardia and cyanosis. Electromyography shows a characteristic almost permanent muscular activity with periods of electrical quietness. Nerve conduction velocity is normal. No specific computed tomography findings have been reported yet. Clonazepam, a gamma aminobutyric acid (GABA) receptor agonist, is the treatment of choice for hypertonia and apnoeic episodes. It, however, may not influence the degree of stiffness significantly. A simple manoeuvre like forced flexion of the head and legs towards the trunk is known to be life saving when prolonged stiffness impedes respiration.
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PMID:Hyperekplexia in neonates. 1152 14

Reflex sympathetic dystrophy is characterized by constant burning pain and hyperesthesia in an extremity. Lower extremities are usually affected. Pain is accompanied by swelling, sweating, vasomotor instability and sometimes trophic changes. There may be a history of minor injury or not. Muscle spasms, myoclonus or focal dystonia may occur. Diffuse pain, loss of function and autonomic dysfunction are three main criteria suggested for diagnosis. Symptoms can last a few days to as long as a year. In this report we present a girl with multiple limb involvement of stage I RSD. The sympathetic skin responses were tested during a remission period. She had milder attacks with a recurrence rate of 4 per year in the following three years from onset.
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PMID:Reflex sympathetic dystrophy in childhood. 1201 58

Botulinum toxin has been a useful treatment in many movement disorders and more recently in other non-neurological motor dysfunctions for more than 15 years. Here, we review the various indications in neurology, mainly in the field of movement disorders. From 1973 to 2002, we searched the Medline database on this topic. We selected the most useful and relevant papers, with a special interest in dystonia. We summarized the results in the main indications (spasmodic torticollis, bleparospasm, hemifacial spasm) and in other manifestations such as writer's cramp, oromandibular dystonia, tremor, tics and myoclonus. We discuss the data of literature and compare them with the experience of the French movement disorders groups.
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PMID:[Movement disorders and botulinum toxin in neurology]. 1292 35

The authors report a Chinese boy with a DYT1 gene mutation having muscle stiffness, severe painful muscle spasm, myoclonus, and dystonia compatible with stiff child syndrome. Autoantibodies to glutamic acid decarboxylase (anti-GAD) were absent. His asymptomatic mother had a DYT1 mutation. His asymptomatic sister has diabetes mellitus and antibodies to glutamic acid decarboxylase but no DYT1 mutation.
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PMID:Stiff child syndrome with mutation of DYT1 gene. 1668 92

A young female patient, who presented acutely with an unusual movement disorder characterized by hyperkinetic facial movements, was referred to us for hemifacial spasm. The only abnormality on neurological examination was myoclonus of the left perioral and bilateral periorbital muscles, exacerbated by mental tasks. A week later, the patient also presented two generalized tonic-clonic seizures on awakening and was successfully treated with antiepileptic drugs. Laboratory and neuroimaging investigations yielded normal findings. Although we were unable to identify a cortical generator, the concomitant occurrence of generalized seizures, the disappearance of symptoms after treatment and the topography of the myoclonus support an epileptic origin of this myoclonus.
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PMID:Focal motor seizures mimicking hemifacial spasm. 1832 23

Infantile spasms syndrome (ISS) is a catastrophic pediatric epilepsy with motor spasms, persistent seizures, mental retardation, and in some cases, autism. One of its monogenic causes is an insertion mutation [c.304ins (GCG)(7)] on the X chromosome, expanding the first polyalanine tract of the interneuron-specific transcription factor Aristaless-related homeobox (ARX) from 16 to 23 alanine codons. Null mutation of the Arx gene impairs GABA and cholinergic interneuronal migration but results in a neonatal lethal phenotype. We developed the first viable genetic mouse model of ISS that spontaneously recapitulates salient phenotypic features of the human triplet repeat expansion mutation. Arx((GCG)10+7) ("Arx plus 7") pups display abnormal spasm-like myoclonus and other key EEG features, including multifocal spikes, electrodecremental episodes, and spontaneous seizures persisting into maturity. The neurobehavioral profile of Arx mutants was remarkable for lowered anxiety, impaired associative learning, and abnormal social interaction. Laminar decreases of Arx+ cortical interneurons and a selective reduction of calbindin-, but not parvalbumin- or calretinin-expressing interneurons in neocortical layers and hippocampus indicate that specific classes of synaptic inhibition are missing from the adult forebrain, providing a basis for the seizures and cognitive disorder. A significant reduction of calbindin-, NPY (neuropeptide Y)-expressing, and cholinergic interneurons in the mutant striatum suggest that dysinhibition within this network may contribute to the dyskinetic motor spasms. This mouse model narrows the range of critical pathogenic elements within brain inhibitory networks essential to recreate this complex neurodevelopmental syndrome.
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PMID:A triplet repeat expansion genetic mouse model of infantile spasms syndrome, Arx(GCG)10+7, with interneuronopathy, spasms in infancy, persistent seizures, and adult cognitive and behavioral impairment. 2012 36


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