Vitamin B12 deficiency in the setting of nitrous oxide abuse: diagnostic challenges and treatment options in patients presenting with subacute neurological complications

Abstract

ABSTRACT Objective It is well recognized that nitrous oxide abuse can lead to vitamin B12 deficiency presenting with neurological complications. Nevertheless, establishing this diagnosis can be challenging, and treatment guidelines are lacking. Methods In this paper, we present a case series of eight patients and discuss the diagnostic challenges and treatment options for vitamin B12 deficiency due to nitrous oxide abuse presenting with neurologic complications. Results Biochemical findings are not always straightforward and complementary testing is often necessary. Magnetic Resonance Imaging (MRI) revealed a longitudinally myelopathy extending over a long segment typically involving the dorsal columns of the cervical cord. To increase the lesion conspicuity, dedicated MRI sequences are needed. In our practice, we recommend the use of T2-weighted images (WI) with fat suppression (FS). Treatment consists of cessation of nitrous oxide abuse and supplementation with intramuscular injections of cobalamin. Due to a lack of treatment guidelines, we also describe the treatment schedule used in our neurology clinic and give a brief overview of treatment options suggested in the literature. Conclusion We described diagnostic steps en treatment plans in patients presenting with subacute neurological complications due to nitrous oxide abuse. Abbreviations crea: creatinine; HCy: homocysteine; MCA: 2-methylcitric acid; MMA: methylmalonic acid; MRI: magnetic resonance imaging; SEP: somatosensory evoked potentials