View source for Nitrous oxide toxicity

==Background==
*Nitrous oxide toxicity is often associated with inhalation of whipped cream or small nitrous oxide cannisters ([[whippets]])
*Commonly abused drug notable for its short-lived euphoric and calming effects through noncompetitive NMDA antagonism and GABA-A agonism.
*Nitrous is much more soluble in blood and will quickly diffuse from the blood to a closed space.
*Beyond the gaseous effects nitrous oxide mainly disrupts B12 by oxidizing the cobalt ion which irreversibly inhibits methionine synthase<ref>Nunn J. Clinical aspects of the interaction between nitrous oxide and vitamin B12. British Journal of Anaesthesia. 1987; 59:3-13</ref>
*Epidemiology
**Rates of nitrous oxide misuse vary significantly by country and are generally higher in Europe and the United States.
**The World Drug Report found nitrous oxide use (i.e. at least once in last 12 months) in 16-24 year olds doubled globally between 2015 to 2021, from 10% to 20%.<ref>United Nations Office on Drugs and Crime. World Drug Report 2021. 2021. [https://www.unodc.org/unodc/en/data-and-analysis/wdr2021.html]</ref>
*Most nitrous oxide misuse is sporadic and without significant health consequences. This and its ease of availability may lead users to erroneously view it as safe.

==Clinical Features==


==Differential Diagnosis==
===Acute complications===
*[[Pneumothorax]] (induced by forceful inhalation or high-pressure tank siphoning)
*Tympanic membrane rupture
*Tracheal trauma
*[[Air emboli]]
*Thrombotic events (rare, typically in subacute toxicity from homocysteine elevation)
**[[Venous thromboembolism]]
**[[Acute arterial ischemia]]

===Chronic complications===
*Bone marrow suppression (from long term exposure)
**[[Leukopenia]]
**[[Megaloblastic anemia]]
**[[Thrombocytopenia]]
*Peripheral neuropathy
*Subacute combined degeneration of the spinal cord

==Evaluation==
*Nitrous oxide use is undetectable by standard drug screens, which makes obtaining a thorough history crucial.<ref>Agarwal P, et al. Recreational nitrous oxide-induced subacute combined degeneration of the spinal cord. Cureus. 2021;13(11):e19377. [https://pmc.ncbi.nlm.nih.gov/articles/PMC8653952/]</ref>
*Neuro deficits:
**Consult poison control for recommendations.
**May be exacerbated in cases of underlying [[B12 deficiency]].
===Workup===

===Diagnosis===

==Management==


==Disposition==


==See Also==
*[[Nitrous oxide]]
*[[Vitamin B12 deficiency]]

==External Links==


==References==
<references/>
[[Category:Toxicology]]