title: An unusual cause of falls in a young woman.
abstract: Nitrous oxide is commonly used as an analgesic and anaesthetic agent. Nitrous oxide is also in use in industry as an aerosol propellant and is now recognised as a recreational drug whose use is growing, especially among the young. Nitrous oxide from whipped cream canisters is inhaled to produce a dissociative, intoxicated state. Nitrous oxide is known to inactivate vitamin B12 via oxidation, which can precipitate a demyelinating myelopathy akin to the classical B12 deficiency syndrome, subacute combined degeneration of the spinal cord. This case describes a young woman with chronic pain and a poor nutritional state who took regular nitrous oxide as an opiate-sparing agent. She developed a progressive subacute myelopathy with a sensory level, profoundly impaired joint position sense, extensor plantars and required a wheelchair. Once diagnosed, she responded well to a regime of nitrous oxide withdrawal, high-dose B12 replacement and physiotherapy. The case illustrates the need for clinical teams to be able to dentify a nitrous oxide-precipitated myelopathy as its use as a drug of abuse increases; particularly in the case of malnourished patients who receive nitrous oxide surgically or obstetrically.
authors.affiliation: I Sleeman Clinical Ageing Research Unit, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne NE4 5LP UK, E-mail isobel.sleeman@ncl.ac.uk.
authors.forename: I
authors.initials: I
authors.lastname: Sleeman
authors.forename: L
authors.initials: L
authors.lastname: Wiblin
authors.forename: D
authors.initials: D
authors.lastname: Burn
mesh_terms: D000058:Accidental Falls; D000328:Adult; D018712:Analgesics, Non-Narcotic / Q000009:adverse effects* / Q000627:therapeutic use; D018685:Anesthetics, Inhalation / Q000009:adverse effects / Q000627:therapeutic use; D059350:Chronic Pain / Q000188:drug therapy*; D003711:Demyelinating Diseases / Q000139:chemically induced* / Q000150:complications / Q000378:metabolism; D005260:Female; D006801:Humans; D009609:Nitrous Oxide / Q000009:adverse effects* / Q000627:therapeutic use; D059408:Pain Management / Q000009:adverse effects; D013118:Spinal Cord Diseases / Q000139:chemically induced* / Q000150:complications / Q000378:metabolism; D014805:Vitamin B 12 / Q000378:metabolism*; D014806:Vitamin B 12 Deficiency
chemical_list: D018712:Analgesics, Non-Narcotic; D018685:Anesthetics, Inhalation; D009609:Nitrous Oxide; D014805:Vitamin B 12
keywords: myelopathy; nitrous oxide; post-anaesthetic complication; recreational drugs