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Query: UMLS:C0027066 (myoclonus)
 4,275 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Reflex myoclonus displays symptomatological heterogeneity involving the cortical and brain stem types that seem to originate above the spinal cord. Three cases of generalized myoclonus proved to be spontaneous and stimulus-sensitive, and increased with action. Segmental spinal myoclonus was spontaneous, stimulus-sensitive and rhythmical and decreased with action. Two cases of post-anoxic myoclonus seemed to be of the reticular reflex in which myoclonus was manifested in all muscles, particularly the proximal ones, and for which the EEG showed no spikes preceding myoclonus. The evoked electromyogram showed a long-loop reflex (LLR) of high amplitude, with no giant somatosensory evoked potential (SEP). Pharmacological examinations showed that the thyrotropin-releasing hormone (TRH) enhanced the onset of myoclonus, shortened the latency of the LLR and increased its amplitude, but caused no remarkable changes in SEP. These results indicate that TRH stimulates the medullary reticular neuron, thereby enhancing reticular reflex myoclonus. The myoclonus of a 3rd case was believed to be cortical reflex myoclonus on the basis of the emergence of giant SEP, increased LLR and the onset of spikes in the EEGs preceding myoclonic jerks, as ascertained by jerk-locked averaging analysis with muscular discharge. Pharmacologically, LLR, SEP and myoclonus showed no definite changes in response to TRH. Segmental myoclonus which seemed to have a spinal origin, showed no giant SEP, enhanced LLR or cortical spikes in the electrophysiological studies. No definite clinical or electrophysiological changes in response to TRH were observed. We believe the TRH administration test may be useful in the differential diagnosis of stimulus-sensitive myoclonus. In addition, the origins and nature of these types of reflex myoclonus are discussed.
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PMID:Electrophysiological and pharmacological studies of somatosensory reflex myoclonus. 155 29

We reported a female infant with early myoclonic encephalopathy (EME). She was diagnosed on the basis of clinical and laboratory features including electroencephalographic and magnetic resonance image (MRI) findings. Frequent erratic myoclonic seizures appeared since 28 days after birth and EEG showed a typical suppression-burst pattern. We administered a high-dose pyridoxal phosphate, thyrotropin-releasing hormone analogue (TRH), and then ACTH, but could not control the seizures at all. With seizure types, we observed the change from erratic myoclonus to tonic spasms in series, with concomitant EEG change to hypsarhythmia at the age of 6 months. Cranial MRI revealed delayed myelination in the white matter but no brain malformation. We administered ACTH to her again and succeeded partially in the decrease of the seizure frequency, and significantly in the improvement of EEG findings. It is supposed that the responsiveness to ACTH treatment changed with age as the seizure patterns developed from erratic myoclonus to tonic spasm.
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PMID:[A longitudinal study of clinical and electroencephalographic findings in a female infant with early myoclonic encephalopathy]. 165 45

The authors investigated the possibility of a thyrotropin-releasing hormone-related mechanism in a 43-year-old Japanese woman with Hashimoto's encephalopathy who experienced three relapses closely associated with the menstrual cycle. Her symptoms began at ovulation, worsened during the luteal phase, and improved during the menstruation phase. No abnormalities were found by brain magnetic resonance imaging and cerebral angiography. Intravenous administration of thyrotropin-releasing hormone induced symptoms of myoclonus and tremor similar to those observed during an exacerbation. The intensity and duration of involuntary movements induced by thyrotropin-releasing hormone were dose-dependent. The patient's symptoms were controlled effectively by thyroxine replacement therapy. On the basis of these findings, thyrotropin-releasing hormone may have an important role in Hashimoto's encephalopathy.
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PMID:Case report: thyrotropin-releasing hormone-induced myoclonus and tremor in a patient with Hashimoto's encephalopathy. 748 24