title: Pseudo-pulmonary embolism as a sign of acute heparin-induced thrombocytopenia in hemodialysis patients: safety of resuming heparin after disappearance of HIT antibodies.
abstract: Heparin-induced thrombocytopenia (HIT) is a syndrome caused by platelet-activating antibodies that recognize complexes of platelet factor 4 (PF4) and heparin. Thrombocytopenia is the most common clinical feature of HIT. HIT can be considered as a hypercoagulable state, with a high risk of thrombosis. Another feature of HIT is an acute systemic reaction that characteristically begins 5-30 min after receiving an intravenous bolus of unfractionated heparin, such as is commonly given for hemodialysis (HD). Here we present 4 patients who developed acute HIT at or near the start of their chronic HD. All patients were anticoagulated with the low-molecular-weight heparin, nadroparin, for HD. Three of our patients underwent surgery approximately 1-2 weeks before developing HIT. All patients presented with an acute systemic reaction during HD. All patients were treated and further dialyzed with lepirudin. Under this treatment we observed a quick recovery of the platelet count, and patients remained symptom-free. Antibodies against the PF4-heparin complex were detected with a combination of a 'quick test' and an enzyme-linked immunosorbent assay test. The likelihood of having HIT previous to the detection of antibodies was estimated with the pre-test probability score criteria. The tests for PF4-heparin antibodies remained positive for an average of 165 days. Three patients underwent a rechallenge with nadroparin after disappearance of the HIT antibodies in their serum. All 3 remained symptomless when they were further hemodialyzed on nadroparin. Our observations indicate that nadroparin can be successfully reintroduced for HD anticoagulation once the patient's HIT antibodies have disappeared.
authors.affiliation: Department of Nephrology, Intensive Care, and Haematology of ZNA Stuivenberg, Antwerp, Belgium.
authors.forename: V
authors.initials: V
authors.lastname: Hartman
authors.forename: M
authors.initials: M
authors.lastname: Malbrain
authors.forename: R
authors.initials: R
authors.lastname: Daelemans
authors.forename: P
authors.initials: P
authors.lastname: Meersman
authors.forename: P
authors.initials: P
authors.lastname: Zachée
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects; D001323:Autoantibodies / Q000276:immunology*; D064420:Drug-Related Side Effects and Adverse Reactions / Q000517:prevention & control; D005260:Female; D006493:Heparin / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000139:chemically induced* / Q000276:immunology* / Q000517:prevention & control; D006435:Renal Dialysis / Q000009:adverse effects; D013921:Thrombocytopenia / Q000139:chemically induced* / Q000276:immunology* / Q000517:prevention & control; D013927:Thrombosis / Q000209:etiology / Q000517:prevention & control; D016896:Treatment Outcome
chemical_list: D000925:Anticoagulants; D001323:Autoantibodies; D006493:Heparin