Koubaissi Salwa A, Degheili Jad A
Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon.
Department of Surgery, Division of Urology, American University of Beirut Medical Center, Beirut, Lebanon.
Am J Case Rep. 2019 Nov 17;20:1691-1694. doi: 10.12659/AJCR.918807.
BACKGROUND Vitamin B12, also known as cobalamin (Cbl), is a major player in both erythropoiesis and myelination of the central nervous system. The 2 main manifestations of vitamin B12 deficiency are bone marrow failure and demyelinating disease. These manifestations also depend on the severity and duration of the deficiency. In severe cases, ineffective erythropoiesis, with intramedullary destruction of erythrocytes has been reported, and increased homocysteine level was shown to be a cause of this hemolysis, . CASE REPORT We present the case of a middle-aged man presented with worsening fatigue, pallor, and dyspnea on moderate exertion. He was found to have a macrocytic anemia associated with intravascular hemolysis and clinical hypothyroidism in the setting of Hashimoto's thyroiditis. Vitamin B12 measured as part of his anemia investigation, was found to be markedly deficient (less than 100 pg/mL). Replacement was started and a reversal of his anemia and hemolysis was shown with improvement in his hemoglobin level upon follow-up. CONCLUSIONS Although a rare presentation, severe vitamin B12 deficiency can lead to hemolysis and severe anemia that can be life threatening. Timely and appropriate diagnosis and replacement, lifelong in some cases, in addition to looking for the underlying cause of this deficiency, and excluding other concomitant hemolytic disorders, is crucial for the management of this reversible disease. Despite some early results, the exact underlying mechanism behind hemolysis is still unclear.
背景 维生素B12，也称为钴胺素（Cbl），是红细胞生成和中枢神经系统髓鞘形成的主要参与者。维生素B12缺乏的两个主要表现是骨髓衰竭和脱髓鞘疾病。这些表现也取决于缺乏的严重程度和持续时间。在严重情况下，已有报道出现无效红细胞生成，伴有红细胞的髓内破坏，并且同型半胱氨酸水平升高被证明是这种溶血的原因。 病例报告 我们报告一例中年男性病例，该患者出现疲劳加重、面色苍白，以及中度运动时呼吸困难。在桥本甲状腺炎背景下，发现他患有与血管内溶血和临床甲状腺功能减退相关的大细胞性贫血。作为其贫血检查的一部分，测得维生素B12明显缺乏（低于100 pg/mL）。开始进行替代治疗，随访时血红蛋白水平改善，显示其贫血和溶血得到逆转。 结论 尽管表现罕见，但严重的维生素B12缺乏可导致溶血和严重贫血，可能危及生命。及时、恰当的诊断和替代治疗（在某些情况下为终身治疗），除寻找这种缺乏的潜在原因并排除其他伴随的溶血性疾病外，对于管理这种可逆性疾病至关重要。尽管有一些早期结果，但溶血的确切潜在机制仍不清楚。
