SHM Converge Scientific Abstract ePoster Gallery-Exposing the Impostor: Severe B12 Deficiency Presenting as Pseudo-Thrombotic Microangiopathy

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This case describes a 40-year-old woman with six weeks of worsening fatigue and dyspnea who was found to have severe macrocytic anemia, thrombocytopenia, and marked hemolysis. Her labs showed hemoglobin 5.5 g/dL, MCV 121 fL, platelets 79,000/µL, LDH 6,483 U/L, low haptoglobin, mildly elevated indirect bilirubin, and an inadequate reticulocyte response. Peripheral smear showed macrocytosis, tear drop cells, and only rare schistocytes.<br /><br />Because these findings can resemble thrombotic thrombocytopenic purpura (TTP), pseudo-thrombotic microangiopathy was considered. However, the absence of neurologic deficits, the presence of macrocytosis, the very high LDH, and the poor marrow response suggested severe vitamin B12 deficiency rather than true TTP. She received intramuscular vitamin B12 and packed red blood cells on day 1, with rapid clinical improvement. By day 2, testing confirmed vitamin B12 deficiency due to pernicious anemia. By day 3, her hemoglobin remained stable, while reticulocytes and platelets rose and LDH fell. Plasma exchange was deferred, and later ADAMTS13 activity returned normal, ruling out TTP.<br /><br />The report emphasizes that severe B12 deficiency can mimic TTP, a dangerous diagnostic pitfall because TTP requires urgent plasma exchange, whereas B12 deficiency is treated with vitamin replacement. Key clues favoring pseudo-TMA include macrocytosis, disproportionately elevated LDH, low reticulocyte production, and minimal schistocytosis. Early recognition can prevent unnecessary procedures, reduce hospital stay, and ensure appropriate treatment.

Asset Subtitle

Kaitlyn A. Bartholomew

Meta Tag

Author List Forough Hakimzada, Kaitlyn A. Bartholomew

Category Clinical Vignettes

Concept Vitamin B12 Deficiency

Concept Thrombotic Microangiopathy

Concept Thrombotic Thrombocytopenic Purpura

Concept Macrocytic Anemia

Concept Thrombocytopenia

Distinguished Non-Finalist

Presenter Organization Mount Sinai Morningside/West

Presenting Author Kaitlyn A. Bartholomew

Track Adult

Keywords

vitamin B12 deficiency

pernicious anemia

pseudo-thrombotic microangiopathy

thrombotic thrombocytopenic purpura

macrocytic anemia

hemolysis

thrombocytopenia

elevated LDH

reticulocyte response

plasma exchange

Vitamin B12 Deficiency

Thrombotic Microangiopathy

Thrombotic Thrombocytopenic Purpura

Macrocytic Anemia

Thrombocytopenia