One month of nitrous oxide abuse causing acute vitamin B 12 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 B12 was 78 pg/mL (58 pmol/L, reference 211-911 pg/mL). The patient had been using nitrous oxide capsules used for whipped cream recharging, which she obtained from other students, a few times daily for a month for the purpose of anxiety relief. The patient was not a vegan or vegetarian. The patient was treated with intramuscular vitamin B12 repletion with partial resolution of neurologic symptoms and discharged on vitamin B12 supplementation.