An unusual cause of falls in a young woman

Nitrous oxide is commonly used as an analgesic and anaesthetic agent. Nitrous oxide is also in use in industry as an aerosol propellant and is now recognised as a recreational drug whose use is growing, especially among the young. Nitrous oxide from whipped cream canisters is inhaled to produce a dissociative, intoxicated state. Nitrous oxide is known to inactivate vitamin B12 via oxidation, which can precipitate a demyelinating myelopathy akin to the classical B12 deficiency syndrome, subacute combined degeneration of the spinal cord.