Unique form of propriospinal myoclonus as a possible complication of an enteropathogenic toxin

Propriospinal myoclonus is an uncommon form of spinal myoclonus propagated, presumably, by slowly conducting polysynaptic intraspinal pathways. Although most patients demonstrate no clear etiology, a variety of disorders have been linked to this abnormal movement, including trauma, multiple sclerosis, tumors, and infectious disorders such as herpes zoster, human immunodeficiency virus, and Lyme disease. We describe 2 young male patients from the same town in Northern Ontario, Canada, exposed to an outbreak of Escherichia coli O157:H7 from contaminated municipal water, who developed identical clinical and electrophysiological features suggestive of a rhythmic form of propriospinal myoclonus with activity alternating between abdominal and paraspinal muscles. A toxin-mediated microvascular thrombosis is proposed as a possible pathogenic mechanism underlying this novel association.