We report on four children with heparin-induced thrombocytopenia type II. In three patients, therapy with unfractionated heparin was associated with development of cardiac thrombi or with thrombosis progression up to the inferior vena cava or with aggravation of peripheral arterial occlusion. In the fourth child, the disease was recognized early on, and no complication occurred. Heparin-induced thrombocytopenia type II was confirmed by heparin-induced platelet activation assay and/or heparin/platelet factor 4-ELISA. Concomitant elevated antiphospholipid antibodies were seen in all patients. Danaparoid sodium applied at a dosage of between 1.2 and 7.1 U/kg/h stopped the disease progression in each patient. Three children had a clinical recovery with partial recanalization, but for the child with peripheral arterial occlusion disease, amputation of some of the toes became necessary.
Conclusion: Our data indicate that heparin-induced thrombocytopenia type II is a potential life-threatening disease in children and danaparoid sodium is beneficial in this age group.