A recent surge of nitrous oxide misuse around London which merits a public health warning

Background: Use of nitrous oxide (N2O) gas for recreational purposes by young people is increasingly recognized as a public health hazard in the UK.Methods: We looked at the hospital records of patients admitted over the last 4 years to a single neurological centre in Essex to determine the demographics, presentation, and management of patients presenting with symptoms of N2O toxicity from its recreational use.Results: Of the 17 patients (mean age = 22.9 +/- 3 years) admitted between September 2018 and October 2022, 70% were admitted between January and October 2022. All patients reported limb paraesthesiae and 16/17 reported (95%) imbalance; 11/17 (65%) showed objective limb weakness. Serum B12 concentration was low in 9/17 (53%). Plasma methylmalonic acid (n = 7) and homocysteine (n = 8) levels were elevated in all patients tested. Spinal cord Magnetic Resonance Imaging (MRI) imaging was abnormal in 10/17 (59%) patients. Nerve conduction studies were abnormal in 10/13 (77%) patients, with evidence of a symmetric, length-dependent, large fibre neuropathy.Conclusions: There has been a recent surge of cases with neurological complications of recreational N2O abuse in the UK, with a relatively greater rate in 2022. Greater awareness of this condition amongst clinicians and health regulators is urgently required to prevent harm from N2O misuse in young people. Key messages: What is already known on this topic Nitrous oxide (N2O) used for recreational purposes causes a functional deficiency of vitamin B12, which can cause serious neurological problems, such as myelopathy and/or neuropathy, with significant disability What this study adds This study confirms that there has been a recent surge in the reported cases of N2O toxicity from recreational use by young people, and based on its public health impact, the UK government has recently enacted a legislation to make the use of N2O for recreation purposes illegal. How this study might affect research, practice, or policy There is a need for local and national guidance on the recognition and management of N2O toxicity. Timely detection and appropriate management in acute medical units are necessary to prevent serious harm. Prolonged clinical surveillance of these patients after discharge from hospital to obtain follow-up data regarding long-term outcomes is imperative.