Reversible nitrous oxide myelopathy and a polymorphism in the gene encoding 5,10-methylenetetrahydrofolate reductase

Pontifical Catholic University of Chile, CiudadSantiago, Santiago Metropolitan, Chile
BJA British Journal of Anaesthesia (Impact Factor: 4.85). 03/2006; 96(2):222-5. DOI: 10.1093/bja/aei300
Source: PubMed

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.

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    • "However, there are unwanted side effects such as bowel distension, postoperative nausea and vomiting [1]. Although rare, N2O has also been associated with serious complications such as myelopathy, megaloblastic anemia and vitamin B12 deficiency [2], as it inactivates vitamin B12, a key enzyme for methionine synthase. In addition, N2O may be harmful to the developing brain in animal study [3]. "
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