II. Epidemiology
- Nitrous Abuse is common among (esp. dentists, Anesthesia professionals, as well as teens)
III. Preparations: Sources
- Nitrous Oxide is widely used in dental Anesthesia
- Used in food industry to generate foam
- Sold illegaly in 10 ml steel bulbs (Whippets)
- Abused by puncturing pressurized bulbs and releasing Nitrous Oxide into a balloon
- Gas is then inhaled from balloon
IV. Pathophysiology
- Acute use
- Chronic use
- Vitamin B12 oxidation and inactivation
- Vitamin B12 is a Cofactor in Methionine synthase
- Decreases production of Methionine and Tetrahydrofolate
- Results in Bone Marrow suppression, decreased DNA synthesis and myelin production
- Also impacts spinal cord degeneration (see below)
- Vitamin B12 oxidation and inactivation
V. Pharmacokinetics
- Peak effect: 30 seconds
- Resolution: 5 minutes
- More than 90% of Nitrous Oxide is exhaled unchanged
- No significant toxic metabolites
VI. Symptoms: Desired Effects by Illicit Users
- Euphoria
- Dissociation
- Hallucinations
- Analgesia
VII. Labs
- Macrocytic Anemia
- Vitamin B12 Level decreased
VIII. Diagnostics
- Spinal MRI
- Central and dorsal spinal cord degeneration
- Nerve Conduction Studies
IX. Adverse Effects: Acute
- Hypoxia
- Nausea
- Light Headedness
- Trauma from Loss of Consciousness (i.e. falls)
X. Adverse Effects: Chronic
- Macrocytic Anemia
- Neurologic effects (general)
- Delusions
- Unusual behavior
- Vitamin B12 Deficiency related effects
- Paresthesias
- Decreased proprioception
- Ataxia
- Hyperreflexia
- Urinary Incontinence
- Paralysis
-
Nitrous Induced Subacute Combined Degeneration of the Spinal Cord
- Nitrous Oxide inhalation interferes with Vitamin B12 Metabolism
- Results in Vitamin B12 Deficiency with secondary long segmental changes involving the Posterior Columns
- See Pathophysiology as above
XI. Management
- Eliminate exposures
- Vitamin B12 Supplementation
XII. References
- Masom and Tomaszewksi (2019) Crit Dec Emerg Med 33(4):28