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

We report 18 patients (13 women, 5 men; age range, 22 to 75 years; mean, 42.5), whom we ultimately diagnosed as having "psychogenic myoclonus." The myoclonus was present for an average of 36 months (range, 1 to 110), and it was segmental in 10, generalized in seven, and focal in one. Stress precipitated or exacerbated the myoclonic movements in 15 patients; 14 had a definite increase in myoclonic activity during periods of anxiety. A combination of the following findings helped to establish the psychogenic nature of the myoclonus: (1) clinical features incongruous with "organic" myoclonus, (2) evidence of underlying psychopathology, (3) an improvement with distraction in 14 and with placebo in nine, and (4) the presence of incongruous sensory loss or false weakness in five. Over half of all patients with adequate follow-up improved after gaining insight into the psychogenic mechanisms of their movement disorder. This study attempts to characterize psychogenic myoclonus, the most common psychogenic movement disorder in our movement disorders clinic, and provides a guide to its diagnosis and treatment.
 ...
PMID:Psychogenic myoclonus. 825 56

Developments in the field of Huntington's disease have focused on the potential benefits of predictive testing. Markers have been described for autosomal dominant cerebellar ataxia and for certain subtypes of Friedrich's ataxia. Argentophilic neuronal and glial inclusions appear to be the first specific pathologic hallmark of multiple system atrophy. "Pure" hereditary spastic paraplegia is not a multisystem disorder of the central nervous system, but a monomorphic and stereotyped disease. Advances in Tourette's syndrome are limited because the presumed gene eludes identification. A new type of myoclonus, propiospinal myoclonus, has been described. Clinical and electrophysiologic criteria for defining primary orthostatic tremor have been proposed. Understanding of the neurophysiologic substrate of essential tremor and myoclonus is improving. New neurologic disorders presenting clinically with prominent movement disorder continue to be described.
 ...
PMID:Choreas, hereditary and other ataxias, tics, myoclonus, and other movement disorders. 850 6

We studied 53 patients (64% females) with static brain lesions who developed progressive movement disorders. Of these, 50 (94%) had dystonia, 17 (32%) tremor, eight (15%) parkinsonism, seven (13%) myoclonus, and three (6%) chorea. The precipitating insults included perinatal hypoxia/ischemia in 22 (42%), stroke in 12 (23%), head injury in eight (15%), encephalitis in eight (15%), and carbon monoxide poisoning, kernicterus, and radiation necrosis in one patient (2%) each. Among the 30 patients with initial insult occurring at age 2 years or younger (Infant group), distribution of dystonia at follow-up was focal in three (10%), segmental in eight (27%), unilateral in 10 (33%), and generalized in nine (30%). The mean latency between the original injury and onset of movement disorder was 25.5 +/- 16.7 years. Among the nine patients who developed dystonia after an insult occurring between ages 6 and 17 (Childhood group), the distribution of dystonia at follow-up was segmental in two (33%) and unilateral in seven (78%); the mean latency of dystonia onset was 4.9 +/- 7.8 years. Of the 14 patients in the Adult group (injury at age 25 or older), 11 developed dystonia, two developed parkinsonism, and one had carbon monoxide encephalopathy and parkinsonism. The distribution of dystonia in the 11 patients at follow-up was segmental in three (27%) and unilateral in eight (73%). The mean latency of movement disorder onset in the 14 patients of the Adult group was 2.5 +/- 4.9 years. No individuals in the Childhood or Adult groups became left-hand dominant; by comparison, nine of the 30 individuals in the Infant group became left-handed. In conclusion, brain injury at a young age is associated with a longer latency to onset of subsequent movement disorder, a greater tendency to development of generalized dystonia, and a greater probability of altered handedness. These tendencies may result from differences in age-related neuroplasticity.
 ...
PMID:Delayed-onset progressive movement disorders after static brain lesions. 890 76

Angelman syndrome (AS) results from lack of genetic contribution from maternal chromosome 15q11-13. This region encompasses three GABAA receptor subunit genes (beta3, alpha5, and gamma3). The characteristic phenotype of AS is severe mental retardation, ataxic gait, tremulousness, and jerky movements. We studied the movement disorder in 11 AS patients, aged 3 to 28 years. Two patients had paternal uniparental disomy for chromosome 15, 8 had a >3 Mb deletion, and 1 had a microdeletion involving loci D15S10, D15S113, and GABRB3. All patients exhibited quasicontinuous rhythmic myoclonus mainly involving hands and face, accompanied by rhythmic 5- to 10-Hz electroencephalographic (EEG) activity. Electromyographic bursts lasted 35 +/- 13 msec and had a frequency of 11 +/- 2.4 Hz. Burst-locked EEG averaging in 5 patients, generated a premyoclonus transient preceding the burst by 19 +/- 5 msec. A cortical spread pattern of myoclonic cortical activity was observed. Seven patients also demonstrated myoclonic seizures. No giant somatosensory evoked potentials or C-reflex were observed. The silent period following motor evoked potentials was shortened by 70%, indicating motor cortex hyperexcitability. Treatment with piracetam in 5 patients significantly improved myoclonus. We conclude that spontaneous, rhythmic, fast-bursting cortical myoclonus is a prominent feature of AS.
 ...
PMID:Cortical myoclonus in Angelman syndrome. 868 90

Chronic acquired hepatocerebral degeneration (CAHD) is a heterogeneous disorder that can occur with a primary neurologic, hepatic, or combined presentation. Little has been added to the understanding of this disorder since the detailed, early clinical and pathological descriptions. The spectrum of clinical presentations can be neuropsychiatric (apathy, lethargy, excessive somnolence), a movement disorder (ataxia, tremor, chorea, parkinsonism, myoclonus, dystonia), or both. Cortical laminar necrosis and polymicrocavitation in the cortex and basal ganglia are combined with cerebral and cerebellar atrophy. Microscopically, Alzheimer type II astrocytes and cytoplasmic glycogen granules are characteristic. Recent neuroradiological observations in patients with liver failure have shown a specific magnetic resonance (MR) imaging appearance with a hyperintense T1 signal in the pallidum, putamen, and, rarely, mesencephalon. Using clues from a similar MR appearance in patients receiving total parenteral nutrition as well as animals given parenteral manganese, and the knowledge that manganese is cleared by the hepatobiliary system, deposition of manganese in the brain is postulated in patients with CAHD. In this review we describe three cases of CAHD with detailed clinical and radiological documentation and discuss the aforementioned pathogenetic mechanisms.
 ...
PMID:Chronic acquired hepatocerebral degeneration: case reports and new insights. 886 9

Observations of rhythmic or semirhythmic myoclonus due to a peripheral nerve lesion are exceptional. We report on a patient with thorax trauma with multiple bilateral hematomas of the paravertebral musculature. Eight years later he developed rhythmic myoclonus of both trapezius muscles and thoracic pain. Infiltration of a paramedially located scar at the level of D5-6 with a local anesthetic agent led to an intermittent relief of the myoclonus as did anesthetic blockade of the left accessory nerve. Surgical excision of the scar, which contained multiple dystrophic axons on histological examination, cured the patient's symptoms as illustrated in a videotape. This indicates that peripheral afferents contributed to the myoclonus. Ephaptic transmission, ectopic excitation, or misdirected neuronal sprouting secondary to the trauma are possible peripheral mechanisms responsible for the movement disorder. Successful blockade of the left accessory nerve with bilateral relief of the symptoms suggests a secondary, more centrally located mechanism, e.g., in the brain stem, probably driven by an altered afferent input. It is concluded that rhythmic or semirhythmic and focal myoclonus need a careful workup to look for a peripheral cause because such a condition would be accessible for surgical treatment.
 ...
PMID:Bilateral myoclonus of the trapezius muscles after distal lesion of an accessory nerve. 886

This is a comprehensive review of animal models of myoclonus with particular emphasis on posthypoxic myoclonus and other newer chemically induced models. A stimulus-sensitive myoclonus was developed by experimentally inducing cardiac arrest in rats. The etiology, pharmacology, and neurochemistry associated with this model are consistent with posthypoxic myoclonus in humans. The complex etiology of posthypoxic myoclonus and the effectiveness of diverse pharmacological therapies in this movement disorder suggest that multiple interactive neurological mechanisms are operative. The p,p'-DDT-induced animal model of myoclonus differs from posthypoxic myoclonus in terms of its neurochemical and pathophysiological mechanisms. Also, micro-injection of compounds that modulate specific neurotransmitter systems in select brain regions induces myoclonus in normal animals, suggesting that these chemically induced models may be useful in understanding the intricate neurochemical and neuroanatomical mechanisms associated with myoclonus. The experimental evidence demonstrates that these novel animal models of myoclonus have salient neurological characteristics, reasonable predictability of novel antimyoclonic agents, and pathophysiological similarities to the disorder in humans. Thus, these animal models of myoclonus have the potential to provide us with valuable information about the disorder that is not readily obtainable by other means.
 ...
PMID:Animal models of myoclonus. 889 97

Two unrelated patients developed bulbar symptoms, followed within several weeks by spontaneous myoclonus and painful, generalized, stimulus-sensitive jerks triggered by unexpected noises and cutaneous stimuli. They progressed to respiratory arrest and required mechanical ventilation, but both patients subsequently made an almost full recovery. These cases stress the importance of persevering with supportive treatment despite rapid progression of this severe generalized movement disorder. The relationship of brainstem reflex myoclonus to hyperekplexia, progressive encephalomyelitis with rigidity, and the stiff-man syndrome is discussed.
 ...
PMID:Brainstem encephalopathy with stimulus-sensitive myoclonus leading to respiratory arrest, but with recovery: a description of two cases and review of the literature. 891 99

Movement disorders are a well-recognized feature of some patients with cerebral palsy and often require treatment. However, treatments have been symptomatic and empiric, and there have been few pharmacologic studies. The major movement disorders in cerebral palsy are dystonia and the hyperkinesias choreoathetosis and myoclonus. They may occur in combination, often accompanied by spasticity and sometimes by epilepsy. Some drugs are useful treatments for all of these problems, but others may improve one while worsening another. Pitfalls in management include not diagnosing metabolic/degenerative disorders, which may mimic cerebral palsy, or not recognizing reversible complications of cerebral palsy, which may exacerbate symptoms. This review attempts to summarize empiric drug use and recommendations for therapy, drug studies in extrapyramidal cerebral palsy, and prospects for new drugs or models for the problem. Many new pharmacologic agents are available for study in cerebral palsy. Better methods of detecting basal ganglia injury after perinatal injury in asymptomatic infants may allow early intervention in the biologic process of recovery and adaptation.
 ...
PMID:Oral pharmacotherapy for the movement disorders of cerebral palsy. 895 57

Developmental regression is the presenting symptom of most infants with cobalamin (Vitamin B12) deficiency. We present a report of three infants with cobalamin deficiency in which the infants also developed a movement disorder. In each case the mother was a vegetarian and the infant was exclusively breast-fed. In two of the infants, a striking movement disorder consisting of a combination of tremor and myoclonus particularly involving face, tongue, and pharynx appeared 48 h after the initiation of treatment with intramuscular cobalamin. This was associated with marked changes in plasma amino acid levels. Paradoxically, the onset of the movement disorder coincided with overall neurological improvement. The third infant had a persistent focal tremor, which appeared before the commencement of treatment. The movements slowly abated during a 3-6 week period. The presence of a movement disorder in cobalamin deficiency has received less attention than other features, but in a mild form is probably common. It may offer an early clue to the diagnosis before the onset of profound neurological deterioration. The cause of the severe movement disorder that can appear after treatment is not known.
 ...
PMID:The neurological syndrome of infantile cobalamin deficiency: developmental regression and involuntary movements. 899 52


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>