Nitrous Oxide/Whippits-Induced Thoracic Spinal Cord Myelopathy and Cognitive Decline With Normal Serum Vitamin B12.

ABSTRACT

Abuse of nitrous oxide leads to irreversible neurologic deficits. Nitrous oxide is commonly abused through the inhalation of whipped cream canisters. These whipped cream chargers, also known as "whippits," are widely available in the United States and their sale is unregulated. There is an increasing prevalence of whippet abuse, and many are unaware of the catastrophic effects. The mechanism of injury is mediated through severe depletion of vitamin B12. Here, we report a case of nitrous oxide abuse leading to thoracic cord myelopathy. The patient has been inhaling approximately 80-100 nitrous oxide canisters daily for three months total. A magnetic resonance imaging (MRI) of the spinal cord illustrates the lesion within the thoracic cord. Further diagnostic workup with serum vitamin B12 levels was normal. However, elevated levels of methylmalonic acid (MMA) were seen. Despite supplementation of vitamin B12, the patient's neurologic deficits persisted, and he was referred to a rehabilitation center. The abuse of whippets is a serious public health threat and warrants greater regulation of their sale. MMA and holotranscobalamin (holoTC) are improved biomarkers for diagnosing vitamin B12 deficiency.