Introduction:

Nitrous oxide is an active ingredient in aerosol spray propellants such as whipped cream cannisters and cooking sprays that may be inhaled in order to achieve a euphoric state. Nitrous oxide can lead to functional vitamin B12 deficiency by oxidizing cobalt ions in vitamin B12 and rendering it inactive—leading to demyelination within the central and peripheral nervous system, commonly presenting as a symmetric subacute combined degeneration of the cord. We present an unusual case of an asymmetric spinal cord presentation from whippets use.

Case Presentation:

A 46-year-old woman presented with complaints of numbness beneath the waist evolving within a 24-hour period without sphincter disturbance. History was notable for recent whippets and cocaine use. Physical exam was notable for asymmetric weakness in the lower limbs with weakness of the left leg (about 3/5 on the MRC scale in most muscle groups) more than the right leg, and proprioceptive sensation loss in the left lower limb below the ankle with only mildly reduced proprioception at the right big toe. A sensory level was present at about the level of the xiphoid process. MRI showed T2 hyperintensities in the dorsal aspect of the spinal cord between C3 and C9. She was treated with high dose vitamin B12, and by discharge there was improvement in her gait and she had regained proprioception in the toes of the left foot.

Discussion:

Our case is unique in that the patient presented with an asymmetric spinal cord presentation, i.e., Brown-Sequard syndrome as a manifestation of her whippets use, which improved with vitamin B12 supplementation. While the use of cocaine may also result in spinal cord involvement, this would more likely present as a vascular cord syndrome and would not be expected to improve with management of vitamin B12 deficiency, as our patient did.