SHM Converge Scientific Abstract ePoster Gallery-The Great Pretender: Vitamin B12 Deficiency-Related Pseudo-Thrombotic Microangiopathy

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This case describes a 40-year-old vegetarian woman who presented with 6 weeks of fatigue, exertional dyspnea, tachycardia, and fever. Her labs showed severe macrocytic anemia and thrombocytopenia: hemoglobin 5.5 g/dL, MCV 121.1 fL, and platelets 79,000/μL. Additional findings included markedly elevated LDH (6483 IU/L), low haptoglobin, mild indirect hyperbilirubinemia, and a low reticulocyte index, raising concern for hemolysis and thrombotic microangiopathy (TMA), such as TTP.<br /><br />However, workup revealed an undetectable vitamin B12 level, with normal ADAMTS13 activity and inhibitor testing, supporting vitamin B12 deficiency-related pseudo-thrombotic microangiopathy (pTMA) rather than true TTP. Her profound deficiency was attributed to pernicious anemia, confirmed by intrinsic factor and parietal cell antibodies, worsened by lifelong vegetarianism. She was treated with intramuscular vitamin B12, with subsequent resolution.<br /><br />The report emphasizes that severe vitamin B12 deficiency should be included in the differential diagnosis of patients who present with hemolytic anemia and thrombocytopenia suggestive of TMA. Key clues favoring pTMA over TTP include very high LDH, macrocytosis, low reticulocyte response, relatively higher platelet counts than typically seen in TTP, and minimal schistocytosis on peripheral smear. Fever can also occur in pTMA, likely from release of proinflammatory nuclear contents. Prompt recognition is important to avoid unnecessary invasive procedures and overtreatment.

Asset Subtitle

Madeleine Reznik

Meta Tag

Author List Hirohide Matsumoto, Karishma Vijay Rupani, Madeleine Reznik

Category Clinical Vignettes

Concept Vitamin B12 Deficiency

Concept Thrombotic Microangiopathy

Concept Vitamin B12 Replacement

Concept Pleural Fluid Lactate Dehydrogenase

Concept Hemolytic Anemia

Distinguished Non-Finalist

Presenter Organization Mount Sinai Morningside-West

Presenting Author Madeleine Reznik

Track Adult

Keywords

vitamin B12 deficiency

pseudo-thrombotic microangiopathy

pernicious anemia

macrocytic anemia

thrombocytopenia

hemolysis

ADAMTS13

trombotic thrombocytopenic purpura

intrinsic factor antibodies

vegetarianism

Vitamin B12 Deficiency

Thrombotic Microangiopathy

Vitamin B12 Replacement

Pleural Fluid Lactate Dehydrogenase

Hemolytic Anemia