“Whippets”‐Induced Cobalamin Deficiency Manifesting as Cervical Myelopathy

Background. Nitrous oxide (N O) is inhaled in anesthesia and as a recreational drug from whipped cream dispensers. Its abuse reaches −10% in some age groups. By inactivating cobalamin (Cbl) (vitamin B12), N O can cause neurologic and hematologic manifestations. We present a case of N O‐induced Cbl deficiency presenting as cervical myelopathy. Case History. After regularly inhaling N O for many months, a 31‐year‐old man developed limb paresthesiae and ataxia over 3 months. Examination revealed finger pseudoathetosis, hyporeflexia, decreased sensation, and gait ataxia. Brain magnetic resonance imaging (MRI) was normal, but the posterior columns of the cervical and upper thoracic cord revealed patchy nonenhancing hyperintense lesions. Serum Cbl was 98 pg/mL (normal = 170–900 pg/mL). Cbl replacement led to recovery within 3 months.Discussion. This patient presented with the symptoms and signs of Cbl deficiency. The MRI lesions in the posterior columns aided the diagnosis. Physicians need to have a high level of suspicion in cases of unexplained Cbl deficiency and myelopathy.