LAUSR

Recreational use of nitrous oxide (N2O) is a growing practice in France and all around the world and is often associated with neurological complications. We report detailed clinical and paraclinical presentations of 12 patients with combined degeneration of the spinal cord and peripheral neuropathies in relation to N2O consumption, possibly favored by lockdowns due to SARS-CoV-2 pandemic. With variable levels of consumption, the 12 patients presented spinal cord and/or peripheral nerve damage, with mostly motor and ataxic symptoms, motor axonal nerve damage, and medullary T2-weighted hyperintensities on MRI. There was a clear improvement in symptoms after vitamin B12 substitution, although some sequelae remained, particularly sensory. We report detailed clinical, electrophysiological, radiological, and biological consequences of N2O abuse in 12 patients. Our data support the clinical and paraclinical observations reported in the literature. The mechanisms of neurological N2O toxicity are still debated. There is currently no precise recommendation on the therapeutic management. The clinical evolution after vitamin B12 substitution seems sufficient but could depend on early management. Effective messages targeting at risk population, but also the health professionals involved, seem crucial as does a better legal framework for this growing practice.