{
  "abstract": "Background Recreational use of nitrous oxide has become increasingly prevalent. Its abuse is commonly associated with myelopathy and/or neuropathy. However, reports of nitrous oxide-induced neuropsychiatric symptoms remain limited in the literature.Case presentation A 20 year-old male presented to emergency department with 1 day history of delusions, severe agitation and fluctuating conscious state. His family revealed he has used nitrous oxide regularly (3L a day) for three years and had a ‘binge’ with unknown amount 5 days before presentation. He had no other past medical conditions, regular medication or other substance use disorder. His physical examination demonstrated fluctuating consciousness, with no overt signs of myelopathy or peripheral neuropathy. Investigations for common vascular, autoimmune, paraneoplastic, infective or nutritional causes of encephalopathy were unremarkable. Patient’s serum B12 level was normal: 279pmol/L (normal >200 pmol/L). Homocysteine level was severely elevated at 169 mmol/L (normal<12 mmol/L). He was treated with daily intramuscular cyanobalamin for 7 days. He started to show clinical improvement after day 8 of hospital presentation and was discharged home on day 12 with resolution of clinical symptoms.Literature search indicated nitrous oxide can infrequently cause psychiatric disturbance in absence of myelo/neuropathy. Nitrous oxide may induce neurotoxicity via its effect on NMDA receptor or monoamine synthesis, in addition to altering vitamin B12 function.Conclusions Recognising neuropsychiatric disturbance as a rare manifestation of nitrous oxide neurotoxicity is important, as prompt diagnosis and early vitamin B12 supplementation may lead to favourable outcome.",
  "authors": [
    {
      "affiliations": [
        "Westmead Hospital, Sydney, NSW, Australia"
      ],
      "name": "Yitong Shao"
    },
    {
      "affiliations": [
        "Liverpool Hospital, Sydney, NSW, Australia"
      ],
      "name": "Indumathi Singh"
    },
    {
      "affiliations": [
        "Liverpool Hospital, Sydney, NSW, Australia",
        "Southwestern Sydney Clinical School, University of NSW, Sydney, NSW, Australia"
      ],
      "name": "Adeniyi Borire"
    }
  ],
  "title": "3418 Acute neuropsychiatric disturbance due to nitrous oxide abuse in the absence of neuropathy or myelopathy",
  "uid": "3c1a2c72-3dd2-56ca-ae0d-770eab56f9a1"
}