Prolonged misuse of nitrous oxide for recreational purposes can lead to spinal cord demyelination and loss of the ability to walk, neurologists have warned.

A recent sharp rise in nitrous oxide popularity has also prompted health authorities to urge doctors to ask about it when taking a drug history.

In a letter to the Medical Journal of Australia, Sydney doctors reported on seven nitrous oxide users, aged 20-30, who presented with moderate to severe ataxia at Royal Prince Alfred Hospital in 2017 and 2018. The duration of use was 2-12 months.

Five of the patients also had psychiatric symptoms, and nearly every patient estimated use of 100 or more nitrous oxide canisters a day in preceding months.