SHM Converge Scientific Abstract ePoster Gallery-The Silent Thief: Pancytopenia Due to Pernicious Anemia

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This case describes a 59-year-old woman who presented with 6 weeks of fatigue, weakness, poor oral intake, weight loss, and severe pancytopenia with macrocytic anemia. Exam showed marked weakness and hyperpigmentation of the palms and soles, a classic sign of vitamin B12 deficiency. Labs revealed hemoglobin 6.9 g/dL, WBC 1,330/mm³, ANC 350/mm³, platelets 21,000/mm³, MCV 114 fL, elevated LDH, low haptoglobin, low-normal reticulocyte response, normal folate, and very low B12.<br /><br />Peripheral smear showed macrocytosis and hypersegmented neutrophils, suggesting megaloblastic anemia. Because the hemolysis markers and thrombocytopenia raised concern for thrombotic thrombocytopenic purpura, ADAMTS13 testing was performed and was normal, excluding TTP. Bone marrow biopsy showed normocellular marrow with dysplasia and megaloblastic changes, mimicking myelodysplastic syndrome but supporting ineffective erythropoiesis from B12 deficiency. Neurologic testing found loss of vibration sense, and MRI of the cervical and thoracic spine showed dorsal column hyperintensity consistent with subacute combined degeneration.<br /><br />Although intrinsic factor antibodies were negative, elevated serum gastrin and positive antiparietal cell antibodies confirmed pernicious anemia as the cause of B12 deficiency. She was started immediately on daily subcutaneous B12 injections, later transitioned to weekly dosing. Her white count, neutrophils, platelets, and reticulocyte response improved quickly, while anemia and neurologic deficits improved more slowly.<br /><br />The case highlights that severe B12 deficiency can mimic TTP, MDS, and leukemia. It also emphasizes the importance of recognizing skin hyperpigmentation, obtaining both intrinsic factor and antiparietal cell antibodies when evaluating pernicious anemia, and beginning B12 replacement promptly to prevent permanent neurologic injury.

Asset Subtitle

Vasu Malhotra

Meta Tag

Author List Camila Villacreses, MMrhaf Alsamman, Michael Sabina, Robert Mendez, Shreya G. Patel, Vasu Malhotra

Category Clinical Vignettes

Concept Vitamin B12 Deficiency

Concept Subacute Combined Degeneration

Concept Pernicious Anemia

Concept Pancytopenia

Concept Macrocytic Anemia

Distinguished Non-Finalist

Presenter Organization Lakeland Regional Health

Presenting Author Vasu Malhotra

Track Adult

Keywords

vitamin B12 deficiency

pernicious anemia

pancytopenia

macrocytic anemia

hypersegmented neutrophils

subacute combined degeneration

ADAMTS13

myelodysplastic syndrome mimic

antiparietal cell antibodies

skin hyperpigmentation

Vitamin B12 Deficiency

Subacute Combined Degeneration

Pernicious Anemia

Pancytopenia

Macrocytic Anemia