Abstract Introduction Vitamin B12 deficiency most commonly presents with megaloblastic anemia, neurologic abnormalities, and gastrointestinal symptoms. However, severe cases of B12 deficiency can rarely present as pseudo-thrombotic microangiopathy (pseudo-TMA), with symptoms of encephalopathy, anemia, and thrombocytopenia. Pseudo-TMA mimics the classic presentation of thrombotic thrombocytopenic purpura (TTP), a life-threatening condition requiring urgent plasmapheresis. This case highlights a rare presentation of pernicious anemia causing severe B12 deficiency and pseudo-TMA. Case Presentation A 65-year-old woman with past medical history of gastroesophageal reflux disease presented to the emergency room with confusion. Laboratory evaluation revealed pancytopenia (WBC 3.0, Hgb 7.1, Plt 118), elevated LDH (4,058 U/L), and undetectable haptoglobin. Additional findings included reticulocyte index of 0.9, weakly positive direct Coombs test, and schistocytes on peripheral smear. Imaging was unremarkable. Given the constellation of altered mental status, thrombocytopenia, and hemolytic anemia, TTP was suspected and the patient was admitted to the Intensive Care Unit for plasmapheresis. Subsequent testing showed vitamin B12 level of 92 pg/mL (ref. 211-911). Plasmapheresis was discontinued after one session and empiric B12 supplementation was started. She showed rapid clinical and hematologic improvement. Subsequent testing revealed a normal ADAMTS13 level and positive gastric parietal cell and intrinsic factor antibodies, ruling out TTP and confirming pernicious anemia. Discussion/Conclusion The clinical overlap between TTP and pseudo-TMA presents a diagnostic challenge. TTP is a rare but critical condition characterized by microangiopathic hemolytic anemia due to ADAMTS13 deficiency. In contrast, pseudo-TMA from B12 deficiency arises from impaired DNA synthesis leading to apoptosis of hematopoietic precursors in the bone marrow. This results in pancytopenia and hemolysis within the marrow itself. The PLASMIC score was developed to assist in deciphering when patients with suspected TTP would benefit from early initiation of plasma exchange. In this case, the patient’s score of 5 placed her in the intermediate risk category. While the urgency of TTP necessitates rapid intervention, clinicians must remain vigilant for mimickers. Pernicious anemia is an autoimmune condition marked by antibodies against intrinsic factor and gastric parietal cells. Its neurological manifestations, including confusion and paresthesia, further confound the clinical picture. Early recognition and appropriate treatment with lifelong B12 supplementation can lead to rapid hematologic and neurologic recovery. This case highlights the importance of integrating clinical scoring systems with laboratory testing to distinguish between true TTP and its mimics. A multidisciplinary approach and awareness of pseudo-TMA can assure appropriate long-term treatment. This abstract is funded by: None
Poluch et al. (Fri,) studied this question.