Segmental spinal myoclonus and syringomyelia : A case report

We report the case of a 75-year-old woman who developed involuntary jerks of the abdominal musculature. They occurred spontaneously or triggered by a forced inspiration or attempts to rise from the supine position. Electromyography (EMG) recorded abnormal bursts of muscle activity in the abdominal, thoracic paraspinal, and intercostal muscles up to the 3rd intercostal space. The bursts were bilateral, arrythmic and synchronous in all muscles. Magnetic resonance imaging (MRI) of the spine revealed a syringomyelic cavity between the T3 and T10 levels. The topological correlation between the EMG muscle activities and the MRI findings was consistent with spinal myoclonus arising from the thoracic spinal cord. The synchronous bursts in muscles depending from few adjacent spinal segments suggested the diagnosis of segmental spinal myoclonus (SSM). There are few reports of SSM related to syringomyelia in the literature.