Ann Rehabil Med.  2019 Aug;43(4):530-534. 10.5535/arm.2019.43.4.530.

Subacute Combined Degeneration Caused by Nitrous Oxide Intoxication: A Report of Two Cases

• Choi C
• Kim T
• Park KD
• Lim OK
• Lee JK

• KMID: 2457762
• DOI: http://doi.org/10.5535/arm.2019.43.4.530

Abstract

We report two cases of subacute combined degeneration (SCD) caused by nitrous oxide (N₂O) gas intoxication, which is rarely reported in Korea. Two patients recreationally inhaled N₂O gas daily for several months. They presented with paresthesia of limbs, voiding difficulty, and gait disturbance. The initial vitamin B₁₂ levels were normal or decreased, but homocysteine levels of the two patients were increased. Magnetic resonance imaging of the cervical spine showed T2-weighted hyperintensity in the bilateral dorsal columns of the cervical spinal cord. Electromyography and somatosensory evoked potential tests for both patients suggested posterior column lesion of the spinal cord combined with sensorimotor polyneuropathy. According to these findings, we concluded that the two patients had SCD. The patient's symptoms partially improved after cessation of N₂O gas inhalation and the receiving of vitamin B₁₂ supplementation therapy. As the incidence of recreational N₂O gas inhalation is increasing in Korea, physicians must be alert to the N₂O induced SCD in patients presenting with progressive myelopathy.

Keyword

Nitrous oxide; Subacute combined degeneration; Vitamin B12

MeSH Terms

Cervical Cord
Electromyography
Evoked Potentials, Somatosensory
Extremities
Gait
Homocysteine
Humans
Incidence
Inhalation
Korea
Magnetic Resonance Imaging
Nitrous Oxide*
Paresthesia
Polyneuropathies
Recreation
Spinal Cord
Spinal Cord Diseases
Spine
Subacute Combined Degeneration*
Vitamin B 12
Vitamins
Homocysteine
Nitrous Oxide
Vitamin B 12
Vitamins

Figure

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  Fig. 1. In case 1, the cervical spine T2-weighted magnetic resonance imaging showed an inverted Vshaped hyperintensity (arrow) in the bilateral dorsal column of cervical spinal cord: (A) sagittal view and (B) axial view at C2 level.

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