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)

Heavily T2-weighted high-field MR images provide a unique opportunity for the evaluation of the extrapyramidal motor system. The images are affected by the presence of small amounts of naturally occurring paramagnetic substances--principally iron--that delineate the neostriatum (caudate and putamen), globus pallidus, red nucleus, substantia nigra, and dentate nucleus, primarily by a decrease in signal secondary to the T2* effect. Movement disorders are associated with either increased or decreased signal or both in these structures, depending on the pathologic process. In the initial evaluation of 113 patients with a variety of movement disorders, good correlation of imaging abnormalities can be made with a simplified schema of the extrapyramidal pathways and a system of classification of abnormal movements, parkinsonism/tremor, dystonia, chorea, myoclonus, and hemiballismus. Parkinsonisms are characterized by abnormalities of the cortico-ponto-cerebello-dentato-rubro-thalamo-cortico-spinal tract or the nigrostriatal tract. Dystonias are characterized by abnormalities of the neostriatum predominantly affecting the putamen. Choreas are also characterized by abnormalities of the neostriatum but predominantly affecting the caudate nucleus. Hemiballismus is characterized by lesions affecting the subthalamic nucleus or associated pathway.
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PMID:Study of movement disorders and brain iron by MR. 244 Feb 91

Clinically relevant movement disorders are identified in 3% of patients with HIV infection seen at tertiary referral centres. In the same setting, prospective follow-up shows that 50% of patients with AIDS develop tremor, parkinsonism or other extrapyramidal features. Hemiballism-hemichorea and tremor are the most common hyperkinesias seen in patients who are HIV positive, but other movement disorders diagnosed in these patients include dystonia, chorea, myoclonus, tics, paroxysmal dyskinesias and parkinsonism. Patients with movement disorders usually present with other clinical features such as peripheral neuropathy, seizures, myelopathy and dementia. In the vast majority of patients, hyperkinesias result from lesions caused by opportunistic infections, particularly toxoplasmosis, which damage the basal ganglia connections. On the other hand, parkinsonism and tremor can result from dopaminergic dysfunction resulting from HIV itself or the use of antidopaminergic drugs. The management of patients who are HIV positive who present with movement disorders involves recognition and treatment of opportunistic infections, symptomatic treatment of the movement disorder and the use of highly active antiretroviral therapy (HAART). The most effective treatment of cerebral toxoplasmosis in patients with HIV infection is the combination of sulfadiazine and pyrimethamine. Symptomatic treatment of the movement disorder is often disappointing: hemiballism improves with antipsychotics, but tremor, parkinsonism and other phenomena usually fail to respond to available therapies. Preliminary data suggest that HAART may be helpful in the symptomatic control as well as prevention of movement disorders in patients who are HIV positive.
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PMID:HIV-related movement disorders: epidemiology, pathogenesis and management. 1226 60