Clinical epidemiological characteristics of nitrous oxide abusers: A single-center experience in a hospital in China

Purpose This study investigated the clinical epidemiological characteristics of nitrous oxide (N2O) abusers in a hospital in China, which have not been systematically reported. Methods The characteristics of patients abusing N2O who were examined and treated at the Affiliated Hospital of Xuzhou Medical University from January 2017 to December 2020 were analyzed. Results A total of 61 patients (average age: 21.7 +/- 3.2 years; 42 male and 19 female) were enrolled; 60.7% of the patients had an education level of high school or lower, and most (59.0%) had no stable occupation. The mean exposure time was 8.5 +/- 7.7 months (range: 1-36 months). Only 52.5% of the abusers reported the physician of the relevant exposure history at the first time of visiting the doctor. The main clinical type was mixed (49.2%). The most common clinical manifestation was distal limb numbness (80.3%). The most frequent outcome was peripheral neuropathy (59%) and subacute combined degeneration (36%). Serum homocysteine level was elevated in 67.5% (27/40) of the patients, while 44.4% (20/45) showed reduced vitamin B12. Note that 61% (22/36) showed abnormal signals in the posterior or lateral funiculus of the spinal cord, and 97% (31/32) of the patients showed peripheral nerve damage by electromyography. In all cases, symptoms were alleviated after halting N2O intake and receiving nutritional neurotherapy. Conclusions N2O abuse can lead to nervous system damage, especially peripheral nerve and spinal cord damage. A full understanding of its clinical epidemiological characteristics is helpful for clinicians to make a timely and clear diagnosis.