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 37-year-old-man was admitted to our hospital because of periodic contraction of the right shoulder muscles of approximately one month's duration. He denied any significant history such as trauma or fever. General physical examination was unremarkable. Neurological examination was also unremarkable except for the periodic synchronous myoclonus involving the right sternocleidomastoid, trapezius, deltoid, rhomboid and serratus anterior muscles. X-ray fluoroscopy demonstrated a synchronized rhythmic contraction of the right diaphragm. The myoclonus was considered to be of spinal origin, because those muscles were innervated by the right fourth and fifth cervical spinal segments. Its frequency was approximately 1.2 Hz. The myoclonus disappeared during sleep. It was enhanced by a voluntary contraction of the corresponding muscles, but mental stress such as arithmetic induced no change in the myoclonus. CBC, serum laboratory data including viral antibody titer, and cerebrospinal fluid were all normal. Radiological examination including MRI showed no abnormal finding. EEG as well as somatosensory evoked potentials following median nerve stimulation were normal. Jerk-locked averaging triggered by the myoclonus of the right deltoid muscle showed no pre-myoclonus spike at the scalp electrodes. Clonazepam (1.5-6 mg/day) and phenytoin (200 mg/day) reduced the rhythmicity as well as frequency of the myoclonus, which then became stimulus-sensitive. The reflex myoclonus was induced by tapping anywhere on the body or by electric shock, but not by flash or sound. There was a refractory period of approximately 800 msec. Lack of the stimulus-sensitivity early in the clinical course could be due to this refractory period.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[A case of stimulus-sensitive segmental spinal myoclonus]. 275 58

Propriospinal myoclonus is one type of myoclonus that is proposed to originate in the spinal cord and spread up and down via propriospinal tract. There are a few reports describing the detailed electrophysiological findings of this myoclonus. In this communication, we present the results of electrophysiological analysis of a patient with propriospinal myoclonus. A 23-year-old woman suddenly noticed abdominal pain, which spontaneously faded in a few hours. Irregular involuntary flexion jerks of the trunk appeared spontaneously without pain or hiccups after this episode. It involved the bilateral axial muscles; sternocleidomastoid muscles (SCM), paravertebral muscles (PVM), abdominal muscles (ABD), and intercostal muscles (ICM), but not the limb muscles. It was worsened by the mental stress, but not by her posture or position. While she slept, the jerks were not observed. Routine laboratory examinations were all normal. Magnetic resonance imaging of the spinal cord revealed no abnormalities. The electrophysiological studies done on this patient are polymyography, back-averaging of the EEG activity preceding spontaneous jerks (jerk-locked averaging (JLA), and movement related cerebral potential (MRCP) preceding the involuntary jerks and voluntary abdominal movements. No EEG activities preceding the myoclonus were demonstrated by JLA or MRCP. No MRCP recorded preceding the myoclonus suggests that the jerk is not a self-initiated or externally triggered voluntary movement. Polymyography revealed that the jerks involved the bilateral axial muscles including SCM, PVM, ICM, and ABD, but not the limb muscles. Homologous muscles were activated synchronously. The duration of EMG bursts was variable ranging 50 to 250 ms in these muscles.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Propriospinal myoclonus--a case report]. 825 30

The authors analyzed rhythmical involuntary movements at rest, which appeared as complications in 12 (sporadic 11, hereditary 1) out of a total of 139 cases (sporadic 99, hereditary 40) of olivo-ponto-cerebellar atrophy. These movements tended to be seen in patients with sporadic OPCA of longer illness duration and at more advanced stages. They were distributed over the face, neck and extremities. Palatal myoclonus was observed in only one case. The movements were exacerbated by maintenance of a fixed posture, motion and mental stress, and stopped during sleep. In some cases, clonazepam, trihexyphenidyl or 1-Dopa was effective. In the surface electromyogram, rhythmical grouped discharges of 2-4 Hz were recorded only on agonist muscles or on both agonist and antagonist muscles synchronously, which is characteristic of skeletal myoclonus. However, pathological study of 3 cases with involuntary movements revealed marked putaminal degenerations as compared with 3 uncomplicated cases. This suggests that these rhythmical movements might be related to parkinsonian tremor.
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PMID:[Rhythmical involuntary movement at rest associated with olivo-ponto-cerebellar atrophy (OPCA)]. 833 81

A 75-year-old Japanese man who had a past history of epilepsy was admitted because of rhythmical myoclonus of upper and lower extremities. His mother and son also had both epilepsy and myoclonus. On neurological examination, he was alert and oriented without dementia. There was no abnormal finding except for the myoclonic jerks appearing in his upper and lower extremities. The myoclonic jerks appeared at rest and worsened during maintaining posture. Results of laboratory tests were all within normal levels. Brain MRIs were normal, and his EEGs showed diffuse fast wave activities without paroxysmal discharges. Surface EMG studies revealed irregular myoclonic discharges at the frequency of 6-20 Hz. Electrophysiologically, he had a giant somatosensory-evoked potentials, an enhanced long-loop reflex(C-reflex) and cortical spikes preceding the myoclonic jerks, suggesting that his myoclonus was of cortical origin. Based on the cortical myoclonus, episodes of epilepsy and familiarity, he was diagnosed as having familial essential myoclonus and epilepsy(FEME). In addition, he periodically became a motionless state characterized by sudden appearance of transient akinesia with generalized stiffness of all of his limbs. The transient motionless state usually appeared following mental stress or sudden sensory stimuli such as loud sound. It persisted for about 10-20 min and ceased spontaneously. Since EEGs recorded during this akinetorigid state showed no paroxysmal discharges, it was considered not to be epileptic. However, after the administration of valproate, his cortical myoclonus improved, and the transient akinetorigid state also disappeared simultaneously. From symptomatic point of views, this generalized motionless state with stiffness of limbs may resemble to freeze behavior of wild animals suddenly confronted with sudden strong stimuli. From symptomatological as well as genetic aspects, FEME has been suggested to be heterogeneous. We propose that this unique akinetorigid attack might be a new clinical phenotype of FEME.
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PMID:[A case of the familial essential myoclonus and epilepsy presenting behavioral arrest]. 1275 39

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