Case report: Subacute combined degeneration of the spinal cord due to nitrous oxide abuse

BackgroundNitrous oxide (N2O) is an increasingly popular recreational drug. N2O irreversibly disturbs the metabolism of vitamin B-12, resulting in a functional deficiency. Vitamin B-12 is vital for myelin synthesis and its deficiency primarily produces neurological complications. Inhaling N2O is more common and neurological complications are more evident than before. Case presentationWe report a young man who developed progressive limb numbness and unsteady walking after N2O abuse. The dominant diagnosis was subacute combined degeneration of the spinal cord (SCD). The patient was admitted to the hospital and given adenosylcobalamin treatment, but his symptoms progressed significantly from before and he developed acute cognitive impairment. After methylprednisolone combined with vitamin B-12 treatment, symptoms significantly improved. ConclusionClinicians need to understand the presentation and treatment of SCD caused by N2O abuse. When symptoms progress despite conventional vitamin B-12 therapy, the combination of methylprednisolone and vitamin B-12 may be considered.