Clinical Presentation of Subacute Combined Degeneration in a Patient With Chronic B12 Deficiency.

Background: Subacute combined degeneration (SCD) is a rare complication of chronic vitamin B12 deficiency that presents with a variety of neurologic findings, including decreased sensation in the extremities, increased falls, and visual changes. Treatment of SCD involves prompt replacement of vitamin B12 and addressing the underlying conditions that cause the deficiency. Given the prevalence of B12 deficiency in the older adult population, clinicians should remain alert to its possibility in patients who present with progressive neuropathy. Case Presentation: This report presents a case of a patient with progressive SCD secondary to chronic B12 deficiency despite monthly intramuscular B12 injections. Conclusions: Appropriate B12 replacement is aggressive and involves intramuscular B12 1000 mcg every other day for 2 to 3 weeks, followed by additional IM administration every 2 months before transitioning to oral therapy. Failure to adequately replenish B12 can lead to progression or lack of resolution of SCD symptoms.