Abbott Daniel W, Friedman Kenneth D, Karafin Matthew S
Department of Pathology, Medical College of Wisconsin, Milwaukee, WI, USA.
Division of Benign Hematology, Medical College of Wisconsin, Milwaukee, WI, USA; Medical Sciences Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA.
Transfus Apher Sci. 2016 Dec;55(3):318-322. doi: 10.1016/j.transci.2016.08.005. Epub 2016 Sep 28.
Thrombotic thrombocytopenic purpura (TTP) is a microangiopathic hemolytic anemia that requires emergent treatment with plasma exchange and is one of the most important conditions for which apheresis service professionals are consulted. Careful interpretation of initial laboratory values and the peripheral blood smear is a critical first step to determining the need for plasma exchange because other conditions can show deceptively similar red cell morphology, and ADAMTS13 levels are often not rapidly available.
We report a case of a patient who was initially diagnosed with TTP and treated with plasma exchange based on preliminary laboratory data and a peripheral blood smear that contained bizarre microcytic red blood cells presumed to be schistocytes. The peripheral blood smear was later interpreted by the hematopathologist to be inconsistent with TTP, and further workup led to a diagnosis of severe vitamin B12 deficiency secondary to pernicious anemia.
This case highlights the diagnostic complexity of thrombotic microangiopathies and the importance of a critical evaluation of the blood smear and presenting laboratory data when there is a concern for TTP.
血栓性血小板减少性紫癜（TTP）是一种微血管病性溶血性贫血，需要紧急进行血浆置换治疗，是血液分离治疗专业人员会诊的最重要病症之一。仔细解读初始实验室检查值和外周血涂片是确定是否需要进行血浆置换的关键第一步，因为其他病症可能表现出看似相似的红细胞形态，而且ADAMTS13水平往往无法快速获得。
我们报告一例患者，该患者最初根据初步实验室数据和外周血涂片被诊断为TTP并接受了血浆置换治疗，外周血涂片中有形态怪异的小细胞红细胞，推测为裂红细胞。后来血液病理学家对外周血涂片的解读与TTP不符，进一步检查后诊断为恶性贫血继发的严重维生素B12缺乏。
本病例突出了血栓性微血管病的诊断复杂性，以及在怀疑TTP时对血涂片和现有实验室数据进行严格评估的重要性。
