title: Severe myeloneuropathy from acute high-dose nitrous oxide (N2O) abuse.
abstract: BACKGROUND
  Myeloneuropathy from chronic exposure to nitrous oxide has been described. Nitrous oxide irreversibly alters B(12) activation, causing signs and symptoms of B(12) deficiency.
  
  
  OBJECTIVE
  We describe a case of myeloneuropathy secondary to acute use of high-dose nitrous oxide.
  
  
  METHODS
  A 24-year-old man presented to the Emergency Department complaining of numbness and tingling of his hands and feet, as well as worsening clumsiness and gait disturbances after escalating use of nitrous oxide in the prior 2 weeks. He was found to have dysmetria, poor proprioception, decreased sensation to vibration and light touch over his extremities, and a mildly positive Romberg sign. Laboratory test values revealed a normal B(12) level but increased methylmalonic acid and homocysteine levels. The patient was admitted to the hospital and started on a course of B(12) injections. He was discharged after 3 days with daily B(12) supplementation.
  
  
  CONCLUSIONS
  This case demonstrates myeloneuropathic changes secondary to acute high-dose nitrous oxide exposure.
authors.affiliation: Department of Emergency Medicine, New York University/Bellevue Hospital Center, New York, New York 10016, USA.
authors.forename: Rachel S
authors.initials: RS
authors.lastname: Alt
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Morrissey
authors.forename: Maureen A
authors.initials: MA
authors.lastname: Gang
authors.forename: Robert S
authors.initials: RS
authors.lastname: Hoffman
authors.forename: Herbert H
authors.initials: HH
authors.lastname: Schaumburg
mesh_terms: D018685:Anesthetics, Inhalation / Q000506:poisoning*; D003711:Demyelinating Diseases / Q000139:chemically induced*; D006801:Humans; D008297:Male; D009609:Nitrous Oxide / Q000506:poisoning*; D014806:Vitamin B 12 Deficiency / Q000209:etiology*; D055815:Young Adult
chemical_list: D018685:Anesthetics, Inhalation; D009609:Nitrous Oxide