New public health issue: Acute ataxia induced by nitrous oxide abuse in young adults during the COVID-19 outbreak

GENDRE Thierry



Acute ataxia is a diagnostic and therapeutic challenge in the Emergency Room. Historically, Guillain-Barré syndrome (GBS) is the main etiology. However, nitrous oxide (N2O) misuse is an emerging phenomenon and also induces acute ataxia. N2O-induced neurotoxicity remains misleading. We aim to improve its diagnosis and to study its relative frequency during the COVID-19 outbreak.


We retrospectively described 26 consecutive patients evaluated for GBS suspicion and finally diagnosed with N2O-induced neurotoxicity from January 2020 to September 2021. We collected clinical, biological, radiological, and neurophysiological data. We compared these patients to 21 with GBS during the same period. We analyzed the frequencies of N2O-induced neurotoxicity and GBS comparatively to the French COVID-19 incidence.


Seven patients presented for N2O-neurotoxicity during the three lockdowns (March to May 2020; December 2020; April 2021) and 19 after the third lockdown. Between April and September 2021, the occurrence of N2O-neurotoxicity was higher than GBS (21 vs. 8). The disease presented in young adults (mean age: 22.7 years) with acute onset of gait disturbance (62%) or isolated limb paresthesia (38%). The typical presentation included areflexic ataxia with distal muscle weakness. The cranial nerves and the upper limb strength were usually spared unlike in GBS. We observed increased homocysteine in all tested subjects.


In our experience, N2O-induced neurotoxicity has become a more frequent acute ataxia than GBS in the Emergency Room. It is recognizable and needs specific treatment. The sharply increased incidence during the COVID-19 outbreak is perpetuating. This substance abuse is an emerging public health issue for youth.

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