Heparin-induced thrombocytopenia in pediatrics and its therapy. Case-repovt and review of literature

Background. The immun-mediated type of heparin-induced thrombocytopenia (HIT) is a severe complication of heparin therapy. HIT is caused by antibodies of IgG class against multi-molecular complexes consisting of platelet factor 4 (PF4) and heparin. These antibodies crosslink platelet Fcgamma-receptors resulting in platelet activation, platelet aggregation, and thrombin generation. This can lead to new thromboembolic complications during heparin therapy. Case reports. We report a new case of HIT in a newborn and summarize the 51 cases reported in the literature. This analysis shows, newborns and small children develop HIT mostly after heart surgery. In older children, HIT mainly occurs during heparinization due to spontaneous thromboembolic complications. In two children, HIT was induced by heparin for prolonging catheter patency. In all cases, HIT occurred during therapy with unfractionated heparin. After diagnosis of HIT anticoagulation was continued with aspirin, warfarin, danaparoid, lepirudin,or low-molecular-weight heparin. Most children survived HIT, five newborns and one 4-year-old girl died, most likely because of the severity of the underlying disease. Conclusion. Similar to adults, incidence of HIT might be reduced when low-molecular-weight heparins are used instead of unfractionated heparin.