Nitrous oxide induced vitamin B12 deficiency

Two patients with asymptomatic vitamin B-12 deficiency developed a peripheral neuropathy 6-7 weeks after exposure to nitrous oxide during general anaesthesia, and 3 and 11 days after receiving cyclophosphamide. The serum B-12 concentration was less than 20 pmol/l and the symptoms resolved after B-12 replacement. We believe that the neurological symptoms were triggered by exposure to nitrous oxide. A possible novel feature in these patients was the close temporal relationship between the onset of the symptoms and cyclophosphamide treatment, if is possible that cyclophosphamide reduced the availability of remaining B-12 stores. Journal or Clinical Neuroscience (1999) 6 (2), 164-166 (C) 1999 Harcourt Brace & Co. Ltd.