Neurologic degeneration associated with nitrous oxide anesthesia
in patients with vitamin B12 deficiency

Flippo TS, Holder WD Jr.
Department of General Surgery,
Carolinas Medical Center, Charlotte.
Arch Surg. 1993 Dec;128(12):1391-5.


Vitamin B12 (cyanocobalamin) is an integral component of two biochemical reactions in man: the conversion of L-methylmalonyl coenzyme A into succinyl coenzyme A and the formation of methionine by methylation of homocysteine. The transmethylation reaction is essential to DNA synthesis and to the maintenance of the myelin sheath by the methylation of myelin basic protein. Active vitamin B12 contains cobalt in its reduced form (Co+). Nitrous oxide produces irreversible oxidation to the Co++ and Co forms that renders vitamin B12 inactive. Five cases (four from the literature and one new case) are presented in which patients unsuspected of having vitamin B12 deficiency developed subacute combined degeneration of the spinal cord following nitrous oxide anesthesia. Patients with vitamin B12 deficiency are exceedingly sensitive to neurologic deterioration following nitrous oxide anesthesia. If unrecognized, the neurologic deterioration becomes irreversible and may result in death.
Nitrous oxide
Inhaled anaesthetics
Rats on nitrous oxide
Nitrous oxide inhalation
Nitrous oxide: 'laughing gas'
Nitrous oxide: adverse effects
Beta-endorphin/nitrous oxide withdrawal
Nitrous oxide - subjective and rewarding effects
Whipped cream bulbs cause nitrous oxide myelopathy

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