P-MD017. Spinal segmental myoclonus masquerading as a pshycogenic movement disorder

Abstract

Introduction . Spinal generated movement disorders are uncommon. An elderly gentleman presented with distressing jerks of both lower limbs which caused him much social embarrassment. He had received psychiatric treatment for these abnormal muscular spasms without relief. He had become depressed and withdrawn when he first presented to our outpatient department. In view of his clinical presentation, long term video EEG was done with simultaneous EMG recording from the left tibialis anterior muscle. During his hospital stay, this gentleman experienced several involuntary rhythmic contractions of both legs. The movements were characterized by a sudden brief flexion of the trunk and hips with the thighs and legs bending forwards and ankles dorsiflexing. The patient was fully conscious, alert and awake during the attack. These jerks occurred in the recumbent position, but he could lose his balance if they occurred on standing. These attacks were not stimulus sensitive and could be provoked by stress. Myoclonic jerks of both lower limbs were recorded with no EEG correlate. During jerking, EMG recording showed persistent contractions of the left tibialis muscle occurring at frequency of 4–8 bursts per second, with each burst comprising of 4–5 motor unit discharges. The burst of tibialis anterior muscle activity was involuntary and was absent during voluntary leg movements. Results . A routine clinical examination followed by a long-term video EEG with simultaneous EMG clinched the diagnosis of a spinal segmental myoclonus. He underwent spinal decompression surgery with fixation followed by treatment with levetericetam and clonazepam which relieved his symptoms. Conclusion . Spinal generated movement disorders are uncommon and are often attributed to a psychiatric disorder in the absence of a better explanation. We take this opportunity to elaborate on the case details, investigations and the treatment of spinal myoclonus.