| Title | A spontaneous prothrombotic disorder resembling heparin-induced thrombocytopenia. | | Author(s) | Warkentin TE, Makris M, Jay RM, Kelton JG | | Institution | Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada. twarken@mcmaster.ca | | Source | Am J Med 2008 Jul; 121(7):632-6. | | MeSH | Adult
Aged
Antibodies
Female
Humans
Immunoassay
Immunoglobulin G
Male
Platelet Factor 4
Thrombocytopenia
Thrombosis
| | Abstract | BACKGROUND: Antibodies against the "self" protein, platelet factor 4 (PF4), bound to heparin-the cause of immune heparin-induced thrombocytopenia-are believed invariably to be triggered by preceding heparin therapy. We describe a novel syndrome, spontaneous heparin-induced thrombocytopenia, in which clinical and serologic features characteristic of this adverse drug reaction develop in patients despite the absence of preceding heparin therapy.
METHODS: Three patients met the study criteria (clinical and serologic features of heparin-induced thrombocytopenia without preceding heparin exposure), of whom 2 patients were identified among 225 patients (0.89%, 95% confidence interval, 0.11%-3.17%) with serologically confirmed heparin-induced thrombocytopenia recognized during an 18-year period at 1 hospital. The platelet serotonin-release assay was used to detect heparin-dependent immunoglobulin G-induced platelet activation, and 2 enzyme immunoassays were used to detect antibodies against PF4/heparin.
RESULTS: Two patients presented with thrombocytopenia and multiple arterial thrombosis, and 1 patient presented with anaphylactoid reactions after 2 subcutaneous injections of low-molecular-weight heparin. All 3 patients had high levels of platelet-activating anti-PF4/heparin antibodies of immunoglobulin G class at presentation despite the absence of previous heparin exposure. However, each patient did have a preceding infectious or inflammatory event; 1 patient had concomitant antiphospholipid antibodies.
CONCLUSION: Circumstances other than heparin use can trigger a spontaneous disorder that closely mimics heparin-induced thrombocytopenia, further supporting the autoimmune nature of this adverse drug reaction. | | Language | eng | | Pub Type(s) | Case Reports
Journal Article
Research Support, Non-U.S. Gov't
| | PubMed ID | 18589060 |
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