Division of Rheumatology, Department of Internal Medicine, School of Medicine, Eskişehir Osmangazi University, Eskisehir, Turkey.
Department of Internal Medicine, Eskişehir Osmangazi University, Eskisehir, Turkey.
Rheumatol Int. 2019 Apr;39(4):743-750. doi: 10.1007/s00296-019-04268-x. Epub 2019 Mar 14.
Tocilizumab (TCZ) may rarely cause hematological side effects including neutropenia and thrombocytopenia. TCZ is essentially expected to lower the fibrinogen levels to stay within the normal range, but TCZ-induced hypofibrinogenemia has been rarely reported in literature. Although it may remain asymptomatic, hypofibrinogenemia has clinical significance owing to the tendency of the condition to result in bleeding. A 65-year-old female patient with known polymyositis was, approximately 20 years after the diagnosis was made, examined due to elevated acute phase reactants leading to the diagnosis of giant cell arteritis (GCA) and TCZ treatment was initiated as she had former steroid-induced osteoporotic fractures. 1 month after the initial dose of intravenous (IV) TCZ, she presented with ecchymosis and was detected to have hypofibrinogenemia. Following the administration of the second dose, hypofibrinogenemia was detected again. In this review, we have analyzed this patient in addition to the cases in six other articles of TCZ induced hypofibrinogenemia which we found out based on our search strategy. Our aim is to point out a rare side effect of TCZ, hypofibrinogenemia, thus to emphasize a possible bleeding disorder and discuss probable underlying mechanisms.
托珠单抗（TCZ）可能很少引起血液学副作用，包括中性粒细胞减少症和血小板减少症。TCZ 本质上预计会降低纤维蛋白原水平，使其保持在正常范围内，但 TCZ 诱导的低纤维蛋白原血症在文献中很少报道。尽管它可能没有症状，但由于这种情况容易导致出血，因此低纤维蛋白原血症具有临床意义。一名 65 岁的女性已知患有多发性肌炎，在诊断后大约 20 年后，因急性期反应物升高而接受检查，导致巨细胞动脉炎（GCA）的诊断，并开始使用 TCZ 治疗，因为她曾有类固醇诱导的骨质疏松性骨折。在静脉注射（IV）TCZ 的初始剂量后 1 个月，她出现瘀斑，并检测到低纤维蛋白原血症。第二剂后再次检测到低纤维蛋白原血症。在本综述中，我们分析了该患者以及我们根据搜索策略在另外 6 篇 TCZ 诱导低纤维蛋白原血症的文章中发现的其他病例。我们的目的是指出 TCZ 的一种罕见副作用，即低纤维蛋白原血症，从而强调可能存在出血障碍，并讨论可能的潜在机制。
