B-285 Whippits, Nangs, Balloons, and Crackers: Functional Inactivation of Vitamin B12

Background Nitrous oxide (N2O or laughing gas) has been used for many legitimate medical, commercial, and industrial purposes. Recreational use of N2O via ‘Whippit’ or ‘nangs’ is on the rise. Prolonged use of N2O can very rapidly cause functional inactivation of Vitamin B12, leading to disabling neuropsychiatric sequelae. Early diagnosis and vitamin B12 replacement is critical to reducing residual neurological deficits. Methods We present a case illustrating the neurological complications secondary to abuse that had affected B12 activation. A 23-year-old man was brought to the emergency department from police custody who had reportedly been attempting to break into his neighbour’s apartments following a suspected N2O inhalation. He was reported to be experiencing auditory and visual hallucinations, was confused and agitated, and paramedics also witnessed a loss of consciousness for 40 seconds. He reported using ‘whippits’ for recreational purposes, and a considerable amount of N2O canisters were found in his apartment. Results Blood tests identified normocytic anemia (Hb 129 g/L, MCV 99 fL, RDW 20.4) with a normal iron profile. Vitamin B12 was elevated at >1475 pmol/L (RI: >250 pmol/L) and an elevated homocysteine level of >50.0 µmol/L (RI 5.5-16.0 µmol/L), consistent with a functional B12 deficiency. Methylmalonic acid levels were not measured despite pathologists* recommendations. A variety of other blood tests were unremarkable. Eventually, the patient was diagnosed with subacute combined degeneration neuropathy based on the history of nitrous oxide use, clinical presentation, imaging, and laboratory findings. He was treated with intramuscular Vitamin B12 repletion, a neurology follow-up was arranged, and he was counselled on the importance of abstaining from N2O and addiction services in the community. Conclusion Physicians should be aware that abuse of N20 is increasingly common and should also be mindful that a B12 level is difficult to interpret. N20 inhibits B12 activation yet does not reduce B12 levels; thus, methylmalonic acid or homocysteine must be measured.