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Multifocal Stroke From Ozone Gas Emboli

Freund, Paul R. MD; Alshafai, Laila MD; Margolin, Edward A. MD

Section Editor(s): Ko, Melissa W. MD; Cestari, Dean M. MD

doi: 10.1097/WNO.0000000000000754
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Abstract: A 34-year-old man with chronic neck pain was treated with regular cervical paravertebral ozone injections. After his last injection, he experienced a syncopal episode and, upon awakening, was found to have ataxia, aphasia, hemiparesis, and left sixth nerve palsy. Computed tomographic angiography demonstrated intra-arterial gas in the right vertebral artery; multiple posterior circulation infarcts were seen on brain MRI. This case illustrates the potential dangers of paravertebral injections of ozone.

Department of Ophthalmology and Vision Sciences (PRF, EAM), University of Toronto, Toronto, Canada; and

Department of Medical Imaging (LA), University of Toronto, Toronto, Canada.

Address correspondence to Paul R. Freund, MD, 801 Eglinton Avenue W, Suite 301, Toronto, Ontario M5N 1E3, Canada; E-mail:

The authors report no conflicts of interest.

© 2019 by North American Neuro-Ophthalmology Society