Nitrous oxide-induced vitamin B(12) deficiency

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J Clin Neurosci. 1999 Mar;6(2):164-6.

Nitrous oxide-induced vitamin B(12) deficiency.

on M, S, NE, P.

Departments of Clinical Oncology, Auckland Hospital, Auckland, New

Zealand.

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. It is possible that cyclophosphamide reduced the

availability of remaining B(12) stores.