Tran Phu Ngoc, Tran Minh-Ha
Department of Internal Medicine, University of California Irvine School of Medicine, Orange, CA 92868, USA; Division of Hematology-Oncology, Chao Comprehensive Cancer Center, University of California Irvine School of Medicine, Orange, CA 92868, USA.
Department of Internal Medicine, University of California Irvine School of Medicine, Orange, CA 92868, USA; Department of Pathology and Laboratory Medicine, University of California Irvine School of Medicine, Orange, CA 92868, USA.
Transfus Apher Sci. 2018 Feb;57(1):102-106. doi: 10.1016/j.transci.2018.01.003. Epub 2018 Jan 11.
Cobalamin deficiency may result in hematologic characteristics similar to thrombotic microangiopathy (TMA). To facilitate diagnosis, we reviewed reported cases of acquired cobalamin deficiency presenting with TMA features (c.def-TMA).
A literature search identified reports of c.def-TMA. Deficiency was defined as B12 levels of <118 pmol/L. Corrected reticulocyte counts and reticulocyte production indexes were calculated. Clinical features were presented as proportion abnormal and results summarized as medians and interquartile ranges (IQR).
Patient level data was extracted from 41 identified cases. Median age (years) was 43 (30-55) with 21/41 (51%) being female. Cobalamin deficiency was noted in 35/40 (87.5%) but fold increases in MMA and HC were 30 and 6, respectively. The etiology was pernicious anemia in 28/41 (68%) cases. Anemia was both universal and severe, with hemoglobin levels of 55 g/L (4.7-6.6). Hypersegmented neutrophils were noted in 23/37 (62%), schistocytes in 29/38 (76%) and median LDH levels 3981 U/L (2004-5467). The RPI was <3.0% in all patients. Thrombocytopenia occurred in 33/41 (80.5%) with a median platelet count of 91 × 10/L (42-112). Plasma infusion or exchange was initiated in 14/41 (34%) with associated complications in 2 cases.
Reticulocytopenia (RPI of <3.0%) was a universal finding that aids in differentiating c.def-TMA from other causes of hemolysis. C.def-TMA was associated with severe anemia, generally mild-moderate thrombocytopenia, and significant elevations in LDH.
钴胺素缺乏可能导致与血栓性微血管病（TMA）相似的血液学特征。为便于诊断，我们回顾了报道的具有TMA特征的获得性钴胺素缺乏病例（c.def-TMA）。
通过文献检索确定c.def-TMA的报道。缺乏定义为维生素B12水平<118 pmol/L。计算校正网织红细胞计数和网织红细胞生成指数。临床特征以异常比例呈现，结果总结为中位数和四分位数间距（IQR）。
从41例确诊病例中提取患者水平数据。中位年龄（岁）为43（30 - 55），41例中有21例（51%）为女性。40例中有35例（87.5%）存在钴胺素缺乏，但甲基丙二酸（MMA）和同型半胱氨酸（HC）分别升高30倍和6倍。28/41例（68%）病因是恶性贫血。贫血普遍且严重，血红蛋白水平为55 g/L（4.7 - 6.6）。37例中有23例（62%）可见多分叶核中性粒细胞，38例中有29例（76%）可见裂体细胞，中位乳酸脱氢酶（LDH）水平为3981 U/L（2004 - 5467）。所有患者的网织红细胞生成指数（RPI）均<3.0%。41例中有33例（80.5%）发生血小板减少，中位血小板计数为91×10/L（42 - 1 . 血浆输注或置换在41例中有14例（34%）开始，2例出现相关并发症。
网织红细胞减少（RPI<3.0%）是一个普遍发现，有助于将c.def-TMA与其他溶血原因区分开来。c.def-TMA与严重贫血、一般为轻度至中度血小板减少以及LDH显著升高有关。
