Spinal Myoclonus: Is It An Anesthetic Mystery?

The goal is to present a descriptive study related an unprecedent case of spinal myoclonus (SM) following subarachnoid anesthesia (SA). SM are sudden, brief, involuntary non-generalized spasms that can be an adverse effect of drug administration via neuraxial routes. Female, 67y, ASA II, proposed for hip replacement surgery, with normal preoperative exams. 7min after SA with 10mg of bupivacaine 0,5%, no motor blockade observed, and patient complained of unbearable pain in legs and perineum and bilateral, asymmetrical and arrhythmic myoclonic movements in the lower limbs. The latter solved after 48h of general anesthesia and rocuronium perfusion, amongst other therapeutics. Accordingly, intrathecal bupivacaine appears to be the SM most likely cause, regarding the absence of neurologic and electrolyte disorders, spinal cord direct trauma, drug exchange and normal perioperative examination, imaging and laboratory testing.It is mandatory to always take the patients' anaesthetic histories and recognize, treat and report rare anaesthetic complications.

Large fasciculation can clinically manifest as spinal myoclonus; electromyographic and dynamic echomyographic studies of four cases with motor neuron disease

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Four cases with motor neuron disease were studied by surface EMG and dynamic Echo.

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Fasciculation manifesting as myoclonus involved contraction of more muscle fibers.

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Large fasciculation can be a cause of spinal myoclonus.

Objective

Patients with motor neuron disease rarely present with fasciculation which is large enough to be clinically recognized as myoclonus. This study is aimed at elucidating the features of large fasciculation manifesting as myoclonus by using surface electromyography (surface EMG) and dynamic echomyography (dynamic Echo).

Methods

Four patients with amyotrophic lateral sclerosis, two of whom clinically presented with both fasciculation and myoclonus, were studied by using the surface EMG and the dynamic Echo.

Results

At rest, all patients had fasciculation in atrophic muscles, and the surface EMG showed occasional discharges of different waveforms corresponding to fasciculation. During voluntary gentle muscle contraction, the surface EMG showed repetitive discharges in the contracting muscle, which were constant in size and waveform within each muscle. The muscle Echo at rest revealed occasional contractions of a small number of muscle fibers corresponding to fasciculation. During voluntary muscle contraction, the number of muscle fibers involved in the involuntary motor phenomena was larger in the patients who clinically presented with myoclonus compared with other patients who clinically presented only with fasciculation. In a patient who presented with myoclonus, there was no contraction in the antagonist muscle.

Conclusions

Fasciculation involving a large number of muscle fibers clinically manifests as spinal myoclonus.

Significance

Fasciculation involving a large number of muscle fibers can be a cause of spinal myoclonus.

A case of bulbospinal muscular atrophy with large fasciculation manifesting as spinal myoclonus

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A patient with BSMA presenting with myoclonus was studied by using surface EMG.

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The surface EMG during voluntary contraction showed large fasciculation discharges.

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Some of them were large enough to cause joint movements, corresponding to myoclonus.

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The case suggests that large fasciculation can be a cause of spinal myoclonus.

Objective

This paper reports a patient with bulbospinal muscular atrophy (BSMA) who presented with spinal myoclonus, documented by video and surface electromyography.

Case report

A 66-year-old man had progressive gait disturbance, dysphagia, and easy fatigability of all extremities over a period of 4 years. Neurologically, muscle atrophy, fasciculation, and weakness were observed in the bulbar and limb muscles. When the knees were kept in mild flexion in the supine position, fasciculation of the thigh adductor muscles was so large that it caused shock-like involuntary movements of the legs, corresponding to spinal myoclonus. A genetic test revealed 41 repeats of CAG in the androgen receptor gene, and the diagnosis of BSMA was made.

Significance

The present case suggests that extremely large fasciculation can cause spinal myoclonus.

Myoclonus-like involuntary movements following cesarean delivery epidural anesthesia

Spinal myoclonus following neuraxial anesthesia is rare. This report describes a case of myoclonus-like involuntary movement that occurred during the recovery from epidural anesthesia for a cesarean delivery. The patient's symptom improved with the administration of benzodiazepine, and the patient recovered with no neurological sequelae. In conclusion, epidural anesthesia can cause spinal myoclonus, which can be treated with a benzodiazepine.

Spinal-generated movement disorders: a clinical review

Spinal-generated movement disorders (SGMDs) include spinal segmental myoclonus, propriospinal myoclonus, orthostatic tremor, secondary paroxysmal dyskinesias, stiff person syndrome and its variants, movements in brain death, and painful legs-moving toes syndrome. In this paper, we review the relevant anatomy and physiology of SGMDs, characterize and demonstrate their clinical features, and present a practical approach to the diagnosis and management of these unusual disorders.

Propriospinal myoclonus: The spectrum of clinical and neurophysiological phenotypes

Propriospinal myoclonus (PSM) is a rare type of spinal myoclonus characterized by muscle jerks that usually start in the midthoracic segments and then slowly propagate up and down into the spinal cord, resulting in repetitive and irregular jerky flexion, or extension of the trunk, neck, knees and hips. PSM can be symptomatic, but up to 80% of reported cases appear idiopathic. PSM tends to occur especially while the subject is lying down. PSM at sleep onset was first described by experts in sleep medicine. The original electrophysiological features included fixed pattern of muscle activations, slow spinal cord conduction (5-15 m/s), electromyographic burst duration less than 1000 ms, synchronous activation of agonist and antagonist muscles and no involvement of facial muscles. PSM has been reported to be a functional (psychogenic) movement disorder in a number of cohorts. The differential diagnosis between idiopathic PSM and the functional forms is not always straightforward. A consistent polymyographically documented muscle activation pattern may be supportive but by no means sufficient and additional neurophysiological investigations are required. PSM should be differentiated from other movement disorders involving the abdomen and trunk, or occurring at sleep-wake transition. This article offers a comprehensive overview of the spectrum of PSM phenotypes.

Recurrent spinal myoclonus after two episodes of spinal anesthesia at a 1-year interval -A case report-

Spinal myoclonus is an unusual, self-limiting, adverse event that may occur during spinal anesthesia. The exact cause and underlying biochemical mechanism of spinal myoclonus remain unclear. A few cases of spinal myoclonus have been reported after administration of intrathecal bupivacaine. We report a case in which spinal myoclonus recurred after two episodes of spinal anesthesia with bupivacaine at a 1-year interval in a 35-year-old woman. The myoclonus was acute and transient. The patient recovered completely, with no neurologic sequelae.