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.