Contributor: Alicia Oberle, MD

Educational Pearls:

• Nitrous oxide (N₂O) can cause a vitamin B12 deficiency in patients after regular use
• N₂O is used in procedural sedation but also as a popular recreational drug 
• N₂O binds and inactivate B12 in the body, therefore decreasing usable supply
• Lack of B12, which is essential for myelinating nerves, can lead to subacute combined degeneration of the spinal cord
• Presentation may include paresthesias, ataxia, gait changes, or bilateral lower extremity motor weakness
• B12 can be normal on labs, as the B12 is present but activated
• Treatment is daily B12 injections and oral supplementation

References

Stockton L, Simonsen C, Seago S. Nitrous oxide-induced vitamin B12 deficiency. Proc (Bayl Univ Med Cent). 2017;30(2):171-172. doi:10.1080/08998280.2017.11929571

Samia AM, Nenow J, Price D. Subacute Combined Degeneration Secondary to Nitrous Oxide Abuse: Quantification of Use With Patient Follow-up. Cureus. 2020;12(10):e11041. Published 2020 Oct 19. doi:10.7759/cureus.11041

Edigin E, Ajiboye O, Nathani A. Nitrous Oxide-induced B12 Deficiency Presenting With Myeloneuropathy. Cureus. 2019;11(8):e5331. Published 2019 Aug 6. doi:10.7759/cureus.5331

*Image obtained from Wikimedia author Hansmuller and licensed under Creative Commons Attribution-Share Alike 4.0 International license.

Summarized by John Spartz, MS4 | Edited by Erik Verzemnieks, MD

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