Journal of Postgraduate Medicine Medknow Publications and Staff Society of Seth GS Medical College and KEM Hospital, Mumbai, India ISSN: 0022-3859 EISSN: 0972-2823 Vol. 49, Num. 3, 2003, pp. 286

Journal of Postgraduate Medicine, Vol. 49, No. 3, July-Sept, 2003, pp. 286

Letter to Editor

Transient Segmental Spinal Myoclonus due to Spinal Anaesthesia with Bupivacaine

Çelik Y, Bekir Demirel C, Karaca S, Köse Y

Department of Neurology, Trakya University School of Medicine amd Department of Anaesthesia and Reanimation, Istanbul University School of Medicine, Istanbul
Correspondence Address: Department of Neurology, Trakya University School of Medicine amd Department of Anaesthesia and Reanimation, Istanbul University School of Medicine, Istanbul

Code Number: jp03079

Sir,

Involuntary, rhythmic or dysrhythmic movements characterized by rapid contractions in the extremities, which develop as a result of the stimulation of the medulla spinalis by several ways is called spinal myoclonus.[1] The most frequent causes of spinal myoclonus are spinal cord compression, tumours, vascular myelopathy, infections, demyelinating diseases, paraneoplastic syndromes, and trauma to the spinal cord. Spinal myoclonus can also be medication-induced, by drugs given through intrathecal and epidural routes (contrast material, local anaesthetics, analgesics).[2] We report here segmental myoclonus in a patient who received spinal anaesthesia with bupivacaine. A 56-year-old-woman underwent surgery for bilateral leg varices. She was premedicated with 3 mg midazolam following blood pressure, SpO2 and ECG monitoring. She then received 3 ml of 0.5% hyperbaric bupivacaine given by a 22G spinal needle through the L4-L5 interval on the left side and left fowler position. Two hours post anaesthesia the patient began to have bilateral, rhythmic myoclonic movements in the lower extremities. These movements were 5-10 times/minute to begin with, and the severity and frequency increased gradually and reached a maximum value of approximately 30-40/minute. This persisted for 30 minutes and disappeared after another 30 minutes without any neurological sequelae. Neurological examination performed before and after the operation was within normal limits. There was no pathological finding on spinal magnetic resonance imaging (MRI), electromyography, and somatosensory-evoked potential examinations.

There was no history of any involuntary movement in the past and no pathological finding was detected on thoracolumbar MRI performed post surgery. We thus attributed the spinal myoclonus to the spinal anaesthesia. The reasons of central myoclonus were excluded because of normal imaging and electropyhsiologic tools. The patient was followed up for a year during which she remained asymptomatic.

Spinal myoclonus due to spinal anaesthesia is a rare disorder. Although the exact aetiology is unclear, it results from spontaneous, repetitive discharges of the anterior horn cell groups. This discharge can be caused by a catheter or anaesthetic material leading to spinal cord irritation. It resolves totally after removal of the catheter or disappearance of the effect of the anaesthetic material.[3],[4],[5] We did not come across any report of bupivacaine-associated spinal myoclonus in the literature. Anaesthetists and surgeons should watch out for this unusual, reversible adverse event during the use of spinal anaesthesia.

REFERENCES

1.	Brown P. Spinal myoclonus In: Marsden CD, Fahn S, editors Movement Disorders 3 Cambridge; Butterworth-Heinemann; 1994. pp. 459-76.  Back to cited text no. 1">
2.	Ford B, Pullman SL, Khandji A, Goodman R. Spinal myoclonus induced by an intrathecal catheter. Mov Disord 1997;12:1042-5  Back to cited text no. 2">  [PUBMED]
3.	Bagnato S, Rizzo V, Quartarone A, Majorana G, Vita G, Girlanda P. Segmental myoclonus in a patient affected by syringomyelia. Neurol Sci 2001;22:27-9.  Back to cited text no. 3">  [PUBMED]  [FULLTEXT]
4.	Brown P. Myoclonus. Curr Opin Neurol 1996;9:314-6.  Back to cited text no. 4">  [PUBMED]
5.	Hopkins AP, Michael WF. Spinal myoclonus. J Neurol Neurosurg Psychiatry 1974;37:1112-5.  Back to cited text no. 5">  [PUBMED]

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