2003 Volume 36 Issue 8 Pages 1337-1342
Heparin-induced thrombocytopenia (HIT) is a relatively common antibody-mediated drug reaction, but is underestimated as a limb- or life-threatening complication induced by heparin. Here, we report a 69-year-old diabetic man who developed HIT and he was complicated by repeated episodes of clotting in the dialyzer and extracorporeal circuit during hemodialysis (HD). He had been treated 2 times a week with unfractionated heparin. Unexpected clot formation in the dialyzer was observed with a decreased platelet count from 19.8×104/mm3 (day 1) to a nadir of 9.7×104/mm3 (day 14). Each dialysis session required saline or heparinized saline flushes to prevent clotting, while frequent change of the dialyzer was needed. Clotting episodes were observed even after changing the dialyzer membrane and/or anticoagulant agents (nafamostat mesilate or low molecular weight heparin). He developed thrombophlebitis after fundal gastrectomy for early gastric cancer when treated with nafamostat mesilate. A diagnosis of HIT was subsequently confirmed with a positive platelet factor 4-heparin antibody (ELISA assay). Currently, the combined therapy of nafamostat mesilate with oral anticoagulant treatment with warfarin has been used effective for preventing clotting episodes during HD. The HIT management will be achieved with the discontinuation of all forms of heparin exposure and the institution of anticoagulation with an alternative agent. Currently, the direct thrombin inhibitor, argatroban is considered to be best for treatment of HIT, but it is not approved in Japan. We have no choice other than the institution of nafamostat mesilate in conjunction with anti-platelet drugs or warfarin. Since patients on HD are repeatedly exposed to heparin, one might expect a higher frequency of HIT. However, the recognition and treatment of patients with HIT is still unsatisfactory. The prevention of this severe complication should be considered as an important goal especially in HD patients.
