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Neurological Rehabilitation

No Laughing Matter: A Case Report of Subacute Combined Degeneration Secondary to Nitrous Oxide Use

Thursday, October 23, 2025
5:00 PM - 6:30 PM MT
Location: Open Kiosks
Has Audio

    Primary Author(s)

  • Morgan E. Caselli, MD

    Resident Physician
    State University of New York (SUNY) Upstate Medical University PM&R Program
    Syracuse, New York

    • Poster Presenter(s)

  • Kathlin Wolfe, MD

    Assistant Clinical Professor
    SUNY Upstate
    Syracuse, New York

Disclosure(s):
Morgan E. Caselli, MD: No financial relationships to disclose
Kathlin Wolfe, MD: No financial relationships to disclose
Case Diagnosis: 43-year-old male with subacute combined degeneration (SCD)

Case Description or Program Description: The patient presented to the emergency department with low back pain, bilateral lower extremity parasthesias, and progressive weakness for 1 month. The weakness led to his utilizing a cane, a walker, and ultimately a wheelchair. Hyperreflexia was noted on physical exam and magnetic resonance imaging of the spine showed longitudinal enhancement in the dorsal column and lateral corticospinal tracts consistent with SCD of the cervical and thoracic regions. Lab work revealed low vitamin B12 and elevated methylmalonic acid levels. The patient refused intramuscular (IM) supplementation and therefore was started on oral vitamin B12 daily. Further discussion with the patient during his hospital stay revealed a 1-year history of daily recreational use of nitrous oxide (NO).

Setting: Skilled Nursing Facility (SNF)

Assessment/Results: The patient was subsequently admitted to a rehabilitation SNF for 10 days and progressed from moderate assistance to modified independence with most activities of daily living. Additionally, he began utilizing a walker for short distances. The patient received IM vitamin B12 while admitted to the SNF, however he refused to continue it as an outpatient and was discharged on oral vitamin B12 daily.

Discussion (relevance): Vitamin B12 serves as a cofactor in the biochemical reactions necessary to produce deoxyribonucleic acid and myelin. NO inactivates vitamin B12, halting these reactions and potentially causing SCD. With a rise in NO popularity, there have been several documented cases of SCD secondary to NO use.

Conclusions: When evaluating vitamin B12 deficiency, physicians must be diligent in obtaining a detailed history including recreational drug use as this information may not be readily disclosed.