Subacute combined degeneration (SCD) of the spinal cord is a disease affecting the lateral and posterior columns of the spinal cord, primarily due to demyelination. It most commonly presents in patients deficient in vitamin B12, producing hematological and neurological manifestations. The condition commonly presents with sensory deficits, paresthesia, weakness, ataxia, and gait disturbances. Vitamin B12 is an active cofactor in the synthesis of deoxyribonucleic acid (DNA) and myelin. It can be caused by inadequate oral intake of vitamin B12 and poor absorption of vitamin B12 due to gastrectomy, ileal resection, intake of certain medications, or bacterial overgrowth.
SCD can be caused by the use and misuse of nitrous oxide. It can also be caused by copper deficiency resulting from excessive zinc consumption.[3] These are less common yet important causes to recognize in clinical practice. Unexplained anemia, coupled with neurological symptoms, should raise suspicions of SCD, and an evaluation investigating vitamin B12 or, less commonly, copper deficiency in susceptible populations should be initiated.
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