Functional Recovery in a Young Adult With Spinal Cord Injury Secondary to Vitamin B12 Deficiency and Substance Use: A Case Report.

Vitamin B12 deficiency is a well-established cause of spinal cord dysfunction, often manifesting as subacute combined degeneration. However, in young adults, especially those with a history of substance use, this diagnosis can be delayed or misattributed to other causes. We present the case of a 26-year-old woman with a history of nitrous oxide and ketamine use who developed significant functional decline and was ultimately diagnosed with B12 deficiency-related spinal cord injury. Despite normal spinal magnetic resonance imaging, she exhibited profound bilateral lower extremity weakness and neuropathic pain. Intensive inpatient rehabilitation resulted in significant functional improvement. This case underscores the importance of early recognition and a multidisciplinary approach to recovery, even in radiographically silent presentations.