Progressive Decrease in Function and Ambulation Potential: A Case of Subacute Combined Degeneration.

Subacute combined degeneration (SCD) is a reversible cause of posterior and lateral spinal cord degeneration. Prolonged vitamin B12 deficiency is a common cause of SCD as it leads to inhibition of proper myelin synthesis and reduces myelin integrity. When left untreated, SCD causes progressive debility that can lead to irreversible damage. We describe the case of a 49-year-old male patient who presented with one year of worsening weakness, back pain, paresthesias, and gait abnormalities. Laboratory values revealed vitamin B12 deficiency, elevated homocysteine and methylmalonic acid, and megaloblastic anemia. Following a diagnosis of SCD, the patient began treatment with intramuscular vitamin B12, and his pain and ambulation improved considerably in the following weeks. Prompt identification of vitamin B12 deficiency can lead to considerable improvements in function and quality of life.