SHM Converge Scientific Abstract ePoster Gallery-Could Your Vitamin B(12) Any Lower?

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A 39-year-old man with a 20-year strict vegan diet presented with paresthesias in both arms, fatigue, shortness of breath, imbalance, light-headedness, and months of confusion and word-finding difficulty. He also reported weight loss, night sweats, vision changes, and dark urine. Exam showed pallor and slowed speech.<br /><br />Labs demonstrated pancytopenia, macrocytosis (MCV 103 fL), and evidence of hemolysis due to ineffective erythropoiesis. Blood smear showed hypersegmented neutrophils and marked anisopoikilocytosis consistent with severe vitamin B12 deficiency. His B12 level was undetectable at 50 pg/mL, while folate was normal. Extensive evaluation for alternative causes, including infectious, autoimmune, and hematologic disorders, was unrevealing. Intrinsic factor and parietal cell antibodies were negative, making pernicious anemia less likely.<br /><br />The case illustrates classic hematologic and neurologic consequences of cobalamin deficiency. B12 is essential for DNA synthesis, and deficiency affects rapidly dividing tissues, leading to megaloblastic anemia and pancytopenia. Neurologically, deficiency can damage the posterior and lateral spinal cord columns, causing paresthesias, sensory loss, gait disturbance, ataxia, weakness, and mental status changes; severe cases may progress to subacute combined degeneration.<br /><br />The patient was treated with packed red blood cell transfusions and parenteral vitamin B12, with rapid improvement in mental status and paresthesias. Follow-up showed normalization of B12 and blood counts, with confusion resolved and only mild residual hand tingling.<br /><br />This case emphasizes the importance of recognizing vitamin B12 deficiency in patients with restrictive diets, especially vegan or vegetarian diets, and highlights the potential for both hematologic and neurologic recovery when treated promptly.

Asset Subtitle

Mary Pelling

Meta Tag

Author List Erica Han, Mark Spencer, Mary Pelling, Stephen Kimura, Yoo Mee Shin

Category Clinical Vignettes

Concept Vitamin B12 Deficiency

Concept Neurologic Symptoms

Concept Anemia

Concept Megaloblastic Anemia

Concept Vitamin B12 Replacement

Distinguished Non-Finalist

Presenter Organization Emory University School of Medicine

Presenting Author Mary Pelling

Track Adult

Keywords

vitamin B12 deficiency

cobalamin deficiency

vegan diet

megaloblastic anemia

pancytopenia

macrocytosis

hypersegmented neutrophils

neurologic symptoms

subacute combined degeneration

parenteral B12 treatment

Vitamin B12 Deficiency

Neurologic Symptoms

Anemia

Megaloblastic Anemia

Vitamin B12 Replacement