Abstract
Background/Objectives To describe the clinical features and outcomes of patients with myelopathy and neuropathy due to recreationally inhaled nitrous oxide.
Methods We identified patients presenting with nitrous oxide associated myelopathy from an electronic database of all discharges in a large tertiary hospital between 2016 and 2023. Demographic, clinical features and the results of investigations were recorded. The primary outcome was modified Rankin Scale score (mRS) at least three months after hospital discharge where available.
Results There were 12 patients identified; six women, mean (SD) age 27.5 (5.1) years, range 19–47 years. The most common symptoms were numbness, weakness and mental state changes. Four patients used large amounts of inhaled nitrous oxide and also took over-the-counter vitamin B12 supplements. The median (range) hospital length of stay was 8.5 (2–56) days. Functional independence at last assessment (median [range] of 3 [1–34] months after discharge) was achieved in nine of the patients with three requiring ongoing support for activities of daily living (mRS ³3).
Conclusion/Discussion Nitrous oxide abuse and its neurological complications are an important public health issue. Functional impairment secondary to nitrous oxide myelopathy can take many months to recover. Clinicians should be aware that some patients who use large amounts of nitrous oxide may self-supplement vitamin B12.
