Predictors of functional disability in nitrous oxide induced myeloneuropathy: an observational study.
Ignacio Lopera-Rodríguez, Alicia Silva-Cátedra, Alexandra Rincón-Valencia, Lucía García-Granados, Javier Ciriero-Macías, Elena Guijarro-Albaladejo, Carlota Villar-Rodríguez, Jorge Román-Rueda, Josefina Andrada-Moreno, A. Luque-Ambrosiani, J. Arzalluz-Luque, F. Gómez-Fernández, C. Paradas
Neuromuscular Disorders May 1, 2026 DOI: 10.1016/j.nmd.2026.106460 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort Peer reviewed |
|---|---|
| Sample size | 10 |
| Population | Patients with recreational nitrous oxide-induced neurotoxicity recruited between 2024 and 2025 |
| Measures | mRS |
| Key findings | All 10 patients had hyperhomocysteinemia while only 40% had vitamin B12 hypovitaminosis, supporting homocysteine as a more sensitive marker. Acroparesthesia (90%) and unstable gait (80%) predominated, and spinal MRI showed posterior column hyperintensity in 60%. Patients with poor functional status at discharge (mRS ≥ 2) tended to have radiological signs of myelopathy, more affected spinal segments, and combined cervical and thoracic involvement, suggesting the anatomical extent of spinal cord damage on MRI is the primary predictor of functional outcome. |
Abstract
Recreational nitrous oxide (N₂O) use is an emerging cause of severe neurotoxicity due to vitamin B12 inactivation. This study analyzes the relationship between initial clinical, biochemical and neuroimaging findings and functional disability at discharge in a cohort of 10 patients recruited between 2024 and 2025. All patients presented with hyperhomocysteinemia, while only 40% showed vitamin B12 hypovitaminosis, confirming hyperhomocysteinemia as a more sensitive diagnostic marker. The most common clinical manifestations were acroparesthesia (90%) and unstable gait (80%). Electrodiagnostic testing revealed pure motor axonal or mixed polyneuropathy in the lower limbs in all analyzed cases. Spinal Magnetic Resonance Imaging (MRI) showed posterior column hyperintensity in 60% of patients. In this series, patients with a poor functional status at discharge (mRS ≥ 2), tended to present with radiological signs of myelopathy, a higher number of affected spinal segments on MRIand combined cervical and thoracic involvement. These findings suggest that the anatomical extent of spinal cord damage on MRI is the primary predictor of functional outcome in N₂O-induced myeloneuropathy after discharge.
Citations in the library
Cites 3
- Increase of nitrous oxide-induced neurological disorders – a German multicenter experience Neurological Research and Practice January 16, 2025
- Nitrous Oxide Abuse: Clinical Outcomes, Pharmacology, Pharmacokinetics, Toxicity and Impact on Metabolism. Toxics November 28, 2023
- Nitrous oxide-induced subacute combined degeneration of the cord: diagnosis and treatment Practical Neurology February 22, 2023