title: Reversible nitrous oxide myelopathy and a polymorphism in the gene encoding 5,10-methylenetetrahydrofolate reductase.
abstract: We present a case of a patient who received nitrous oxide on two occasions within a period of 8 weeks and who subsequently developed a diffuse myelopathy, characterized by upper extremity paresis, lower extremity paraplegia and neurogenic bladder. Laboratory testing revealed hyperhomocysteinaemia and low levels of vitamin B(12). Because of this uncommon clinical presentation, we analysed the patient's DNA, and found a polymorphism in the MTHFR gene that is associated with the thermolabile isoform of the 5,10-methylenetetrahydrofolate reductase enzyme, which explained the myelopathy experienced by the patient after being exposed to nitrous oxide. Soon after initiating supplementary therapy with folic acid and vitamin B(12), the neurological symptoms subsided.
authors.affiliation: Department of Anesthesiology and Department of Neurology, Pontificia Universidad Católica de Chile, Santiago, Chile. lacassie@med.puc.cl
authors.forename: H J
authors.initials: HJ
authors.lastname: Lacassie
authors.forename: C
authors.initials: C
authors.lastname: Nazar
authors.forename: B
authors.initials: B
authors.lastname: Yonish
authors.forename: P
authors.initials: P
authors.lastname: Sandoval
authors.forename: H A
authors.initials: HA
authors.lastname: Muir
authors.forename: P
authors.initials: P
authors.lastname: Mellado
mesh_terms: D018685:Anesthetics, Inhalation / Q000009:adverse effects*; D005492:Folic Acid / Q000627:therapeutic use; D020022:Genetic Predisposition to Disease; D006801:Humans; D020138:Hyperhomocysteinemia / Q000150:complications; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D008875:Middle Aged; D009609:Nitrous Oxide / Q000009:adverse effects*; D010243:Paralysis / Q000139:chemically induced; D011110:Polymorphism, Genetic; D011183:Postoperative Complications; D013118:Spinal Cord Diseases / Q000139:chemically induced* / Q000188:drug therapy / Q000235:genetics; D014805:Vitamin B 12 / Q000627:therapeutic use
chemical_list: D018685:Anesthetics, Inhalation; D005492:Folic Acid; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D009609:Nitrous Oxide; D014805:Vitamin B 12