Nitrous oxide is increasingly being used as a recreational drug. Prolonged use of nitrous oxide can have disabling neurological sequelae due to functional inactivation of vitamin B12.
Patients can present with sensorimotor peripheral neuropathy with demyelinating features with no clinical or imaging evidence of myelopathy, emphasizing that not all patients develop subacute combined degeneration of the spinal cord (the typical presentation of functional vitamin B12 deficiency). Diagnosis is mostly based upon the history of nitrous oxide use. Notable abnormal lab values would be raised levels of homocysteine and/or methylmalonic acid. All patients should be treated with parenteral vitamin B12. Timely diagnosis and treatment is important to prevent long term or permanent disability.
Rosenberg H, Orkin FK, Springstead J. Abuse of nitrous oxide. Anesth Analg. 1979 Mar-Apr;58(2):104-6. PMID: 571232.
By: Andrew Chan, PA