One month of nitrous oxide abuse causing acute vitamin B deficiency with severe neuropsychiatric symptoms.

A 21-year-old university student studying abroad in the USA presented to the emergency department with double vision, lower extremity weakness with difficulty ambulating and other neuropsychiatric symptoms. MRI of the brain and spinal cord were normal. Vitamin B was 78 pg/mL (58 pmol/L, reference 211-911 pg/mL).