Disclosures: Monica A. Barnes, DO: No financial relationships or conflicts of interest

Case Description: The patient presented to the hospital with a chief complaint of 3 days of progressive numbness and weakness in bilateral lower extremities after long-term use of recreational nitrous oxide (N2O). Further examination demonstrated ataxia, distal weakness, hyporeflexia, and decreased sensation of vibration and proprioception. Magnetic resonance imaging of the cervical spine demonstrated abnormal signal within the dorsal columns extending from C2-3 through C5, consistent with subacute combined degeneration (SCD). This was associated with a low vitamin B12 level (55ng/mL). The patient was placed on high dose vitamin B12 supplementation and admitted to inpatient rehabilitation (IPR), after which he demonstrated functional improvement.

Setting: Inpatient rehabilitation hospital.

Patient: A previously healthy 19-year-old male. Assessment/

Results: The patient presented with complications secondary to recreational N2O use, including clinical findings of dorsal spinal column and peripheral nerve involvement. His scores for functional independence measures in relationship to transfers, wheelchair mobility, ambulation, dressing, toileting, and stairs improved an average of 3.5 to 4 points per category during his IPR stay. At time of discharge, the patient was independent at a wheelchair level and required minimal assistance to ambulate with forearm crutches and bilateral ankle foot orthoses.

Discussion: Recreational use of N2O is reported to be an increasingly prevalent cause of neurologic deficits. Complications of N2O use have been described as “SCD” or “myeloneuropathy,” and presentation is variable. Good clinical outcomes have been described with high dose vitamin B12 supplementation, however literature regarding rehabilitation in this patient population is scarce.

Conclusion: It is important for physiatrists to recognize the clinical spectrum and management considerations of patients exposed to N2O. We present a case of SCD due to recreational N2O use in which the patient demonstrated functional improvement when treated with aggressive vitamin B12 supplementation and comprehensive rehabilitation.

Level of Evidence: Level IV

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/recreational-nitrous-oxide-use-as-a-cause-of-subacute-combined-degeneration-a-case-report/