Serum copper decrease and cerebellar atrophy in patients with nitrous oxide-induced subacute combined degeneration: two cases report

BACKGROUND: Subacute combined degeneration (SCD) is a neurological complication commonly associated with vitamin B(12) deficiency. It can result from nitrous oxide (N(2)O) abuse and cause neuropsychiatric symptoms. However, there has been no literature regarding alterations of serum copper and cerebellum in SCD patients. CASE PRESENTATION: We reported two cases of young SCD patients with histories of N(2)O abuse. In these cases, elevated homocysteine, macrocytic anemia, spinal cord abnormalities, and peripheral nerve injuries were detected. In addition, decreased serum copper level and cerebellar atrophy were reported for the first time. The patients’ symptoms improved after withdrawal of N(2)O exposure and vitamin B(12) supplements. CONCLUSION: We reported two SCD cases with serum copper alteration and cerebellar atrophy after N(2)O abuse for the first time. These might be crucial complements to the diagnosis of SCD.