Sustained focal effects of low‐dose intramuscular succinylcholine

Walker, Francis O.; Scott, Gregory E.; Butterworth, John

doi:10.1002/mus.880160211

Cited by 10 publications

(5 citation statements)

References 19 publications

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“…One possible explanation of this phenomenon may be related to the effect of repetitive nerve stimulation. There are many reports discussing CMAP variation during prolonged nerve stimulation of the terminal endings (35)(36)(37)(38). In particular, a decrease in CMAP amplitude and glycogen depletion are described.…”

Section: Discussionmentioning

confidence: 99%

The variability in the clinical effect induced by botulinum toxin type A: The role of muscle activity in humans

Eleopra¹,

Tugnoli²,

Grandis³

1997

Movement Disorders

103

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When botulinum toxin (BT) is administered for the first time at fixed doses, variable clinical responses can be observed in patients with the same form of dystonic disorder. Many factors may contribute to this phenomenon, including the variability rate of absorption of the drug. Animal experimental models (rat diaphragm preparation) have demonstrated an increased absorption of BT in the terminal nerve endings of the muscle under repetitive electrical stimulation, suggesting that "muscle activity" also may play an important role. The aim of our study was to evaluate in humans the role of the muscle activity on the variability of the effect induced by BT type A. Eleven patients with blepharospasm and idiopathic facial hemispasm were studied by using neurophysiologic techniques. In nine patients, both extensor digitorum brevis (EDB) muscles were injected with low (3 IU), fixed doses of type A BT. For the first 24 h after administration of the drug, periodic electrical stimulation of only one EDB was used. The subsequent percentage changes in compound muscle action potential (CMAP) amplitude was calculated at different intervals over a 30-day period. The percentage in the CMAP for the stimulated EDB was compared with that of the contralateral nonstimulated side. We found that the effect of the induced neuromuscular blockade was significantly greater for the stimulated side. In the other two patients, we injected BT in one EDB and the same volume of normal saline solution in the contralateral muscle to assess the stability of the CMAP in untreated muscle over time. We observed that the CMAP was unchanged in the untreated EDB; therefore we concluded that muscle activity plays an important role in the variability of clinical response often seen.

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Section: Discussionmentioning

confidence: 99%

The variability in the clinical effect induced by botulinum toxin type A: The role of muscle activity in humans

Eleopra¹,

Tugnoli²,

Grandis³

1997

Movement Disorders

103

View full text Add to dashboard Cite

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“…The root mean square (RMS) of the EMG signal expresses average flows of electrical signals in a window of time and is considered a valid measure of motor unit behavior 12. In this study, we used the RMS obtained during a 500‐ms interval around the peak voltage as the reference for maximal voluntary muscle recruitment13, 14 to perform agonist recruitment index (ARI) and cocontraction index (CCI) calculations in specific time windows.…”

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confidence: 99%

Spastic cocontraction in hemiparesis: Effects of botulinum toxin

et al. 2012

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“…Desensitization was observed with the decrement pattern of repetitive nerve stimulation. Persistent accumulation of acetylcholine (or acetylcholine agonists such as succinylcholine [ 17 ]) leads to a reduction of the number of functioning nicotinic receptors at the post-synaptic junction. This may be due to downregulation or conformational change of the receptor in response to acetylcholine, but there may also be direct effects of high concentrations of organophosphorus insecticide at the neuromuscular junction [ 18 ].…”

Section: Discussionmentioning

confidence: 99%

Serial repetitive nerve stimulation studies in organophosphorus poisoning indicate two distinct pathophysiological processes occur at the neuromuscular junction in the intermediate syndrome

Buckley,

Jayawardane,

Weerasinghe

et al. 2024

Clinical Toxicology

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Introduction Intermediate syndrome is an important cause of respiratory failure following acute organophosphorus pesticide poisoning. The objective of this study was to examine the pathophysiology of this syndrome by analysis of sequential repetitive nerve stimulation studies in patients with acute organophosphorus pesticide poisoning. Methods Thirty-four consenting symptomatic patients with acute organophosphorus pesticide poisoning with intermediate syndrome ( n = 10) or a milder forme fruste intermediate syndrome ( n = 24) were assessed prospectively with daily physical examination and repetitive nerve stimulation done on the right and left median and ulnar nerves. The compound muscle action potential at 1, 3, 10, 15, 20 and 30 Hertz was measured with a train of ten stimuli. The amplitudes of the resulting stimuli were normalized to the first stimulus (100 per cent) and plotted against time. The decrease in the area under the curve of all the second stimulus compound muscle action potentials in the first 0.3 seconds was measured as a means of quantifying the refractory block. The decrease in the area under the curve under the 10, 15, 20 and 30 Hertz compound muscle action potentials relative to this pooled second stimulus compound muscle action potentials-area under the curve indicated the extent of additional rate-dependent block (decreasing compound muscle action potential-area under the curve over the first 0.3 seconds after the first stimulus with increasing Hertz). Results These new measurements strongly correlated with the severity of weakness. Refractory block was seen in most patients but was more severe in those with intermediate syndrome than those with forme fruste (partial) intermediate syndrome (median 55 per cent versus 16 per cent, P = 0.0001). Similar large differences were found for rate-dependent block (30 per cent versus 7 per cent, P = 0.001), which was uncommon in forme fruste intermediate syndrome but found in nine out of 10 patients with intermediate syndrome. Rate dependent block was generally only observed after 24 hours. The simplest strong predictor was total block at 30 Hertz repetitive nerve stimulation (89 per cent [interquartile range 73 to 94 per cent] versus 21 per cent [4 to 55 per cent]; P < 0.0001), which was very similar to total block calculated by summing other calculations. Discussion These findings likely represent depolarization and desensitization block from prolonged excessive cholinergic stimulation but it is not clear if these are from pre- or post-synaptic pathology. An animal model of intermediate syndrome with repetitive nerve stimulation studies might enable a better pathophysiological understanding of the two types of block. ...

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Sustained focal effects of low‐dose intramuscular succinylcholine

Cited by 10 publications

References 19 publications

The variability in the clinical effect induced by botulinum toxin type A: The role of muscle activity in humans

The variability in the clinical effect induced by botulinum toxin type A: The role of muscle activity in humans

Spastic cocontraction in hemiparesis: Effects of botulinum toxin

Serial repetitive nerve stimulation studies in organophosphorus poisoning indicate two distinct pathophysiological processes occur at the neuromuscular junction in the intermediate syndrome

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