Heparin-induced
thrombocytopenia (HIT) is a serious adverse effect of
heparin administration. This must not be rarely encountered but is not often reported in Japan compared to Western countries. A 68-year-old woman underwent left upper lobectomy for
lung cancer. Low-dose
unfractionated heparin was administrated to prevent
thromboembolism after the operation. Two days later, sudden
dyspnea appeared and ultracardiosonography showing an extensive thromboembolus from the main trunk to both main branches of pulmonary artery indicated pulmonary embolization. After the establishment of percutaneous cardiopulmonary support (PCPS) support, the
embolus was removed by emergent open heart surgery. However, despite further
unfractionated heparin administration following embolization surgery, other
thrombus was identified in both the bi-lateral internal jagular veins and inferior vena cava by ultrasonography and contrast computed tomography( CT). Her platelet count was decreased gradually despite
platelet transfusion. Plate factor 4( PF4) antibody against
heparin in her blood examination was found, and HIT II was diagnosed. Discontinuation of
unfractionated heparin and administration of
antithrombin agent improved platelet count, and no additional embolization was identified.