The sharp rise of neurological disorders associated with recreational nitrous oxide use in China: a single-center experience and a brief review of Chinese literature

Introduction In recent years, there has been a sharp increase in the number of patients with neurological disorders associated with recreational use of nitrous oxide (N2O) in China. Here, we summarize the clinical characteristics of patients with neurological disorders associated with N2O abuse diagnosed in our Hospital. Further, we conducted a literature search on recent cases reported in mainland China to improve the awareness of the outbreak of neurological disorders associated with N2O abuse. Methods We retrospectively collected data of patients diagnosed with neurological disorders associated with recreational use of N2O in Shengjing Hospital of China Medical University from January 2018 to June 2019, and performed a literature search using the nitrous oxide and neurological disorder as keywords in the Chinese literature databases of WANFANG and CNKI and the English literature databases of Pubmed and Web of Science Results We enrolled 43 patients (average age: 21.9 +/- 3.3 years). The main clinical manifestations were weakness and paresthesia in the four extremities and unsteady gait. Further, most patients showed significantly lower levels of serum vitamin B12 (169.4 +/- 79.1 pg/mL) and increased homocysteine levels (78.1 +/- 32.2 mu mol/L). MRI of the spinal cord showed longitudinal high T2 signal lesions in the dorsal spinal cord in some patients. Moreover, electromyography showed sensory and motor nerve axonal damage combined with demyelination, which was relatively more severe in the lower limbs. There was rapid improvement of the symptoms after treatment with intramuscular injections of vitamin B12 and the overall prognosis was good. The literature search indicated that the number of published papers and related patients showed a rapid annual increase since the first Chinese case reported in 2016 Conclusion Recreational use of N2O is an emerging public health problem in China that needs prompt action from the society and government. Early diagnosis and treatment allow a good overall prognosis.