Division of Pediatric Hematology, The Johns Hopkins University, Baltimore, MD 21205, USA.
Hematology Am Soc Hematol Educ Program. 2011;2011:162-9. doi: 10.1182/asheducation-2011.1.162.
The diagnosis and management of heparin-induced thrombocytopenia (HIT) in pediatric patients poses significant challenges. The cardinal findings in HIT, thrombocytopenia and thrombosis with heparin exposure, are seen commonly in critically ill children, but are most often secondary to etiologies other than HIT. However, without prompt diagnosis, discontinuation of heparin, and treatment with an alternative anticoagulant such as a direct thrombin inhibitor (DTI), HIT can result in life- and limb-threatening thrombotic complications. Conversely, DTIs are associated with higher bleeding risks than heparin in adults and their anticoagulant effects are not rapidly reversible; furthermore, the experience with their use in pediatrics is limited. Whereas immunoassays are widely available to aid in diagnosis, they carry a significant false positive rate. Age-dependent differences in the coagulation and immune system may potentially affect manifestations of HIT in children, but have not been extensively examined. In this chapter, diagnostic approaches and management strategies based on a synthesis of the available pediatric studies and adult literature on HIT are discussed.
肝素诱导的血小板减少症(HIT)在儿科患者中的诊断和管理带来了重大挑战。HIT 的主要表现为肝素暴露后血小板减少和血栓形成,在重症患儿中较为常见,但通常继发于 HIT 以外的病因。然而,如果不能及时诊断、停用肝素并使用替代抗凝剂(如直接凝血酶抑制剂[DTI])进行治疗,HIT 可能导致危及生命和肢体的血栓并发症。相反,DTIs 在成人中的出血风险高于肝素,且其抗凝作用不能迅速逆转;此外,其在儿科中的应用经验有限。免疫测定法广泛用于辅助诊断,但存在显著的假阳性率。凝血和免疫系统在年龄上的差异可能会影响儿童 HIT 的表现,但尚未得到广泛研究。本章讨论了基于对现有儿科研究和成人 HIT 文献的综合分析的诊断方法和管理策略。