Fondaparinux cross-reactivity in heparin-induced thrombocytopenia successfully treated with high-dose intravenous immunoglobulin and rivaroxaban.

Abstract

HIT, a prothrombotic disorder caused by heparin-dependent antibodies, is often treated with fondaparinux, usually with good outcomes. A 70-year-old female developed severe HIT (platelet count, 25 × 109/L) post-glioblastoma resection during heparin thromboprophylaxis, complicated by disseminated intravascular coagulation (DIC) and symptomatic lower-limb deep-vein thrombosis (DVT). Despite therapeutic-dose fondaparinux, thrombocytopenia/hypofibrinogenemia persisted, with new symptomatic catheter-associated upper-extremity DVT. This clinical picture could be explained by autoimmune HIT (aHIT) refractory to fondaparinux or by fondaparinux cross-reactivity, so high-dose intravenous immunoglobulin (IVIG) was given (to treat possible aHIT) and fondaparinux switched to rivaroxaban, with subsequent clinical recovery. In vitro studies revealed strong fondaparinux cross-reactivity, without aHIT antibodies. Moreover, the patient's serotonin-release assay became negative post-IVIG, suggesting in-vivo inhibition of HIT antibody-induced platelet activation. Our case illustrates fondaparinux cross-reactivity in HIT manifesting as persisting thrombocytopenia, new thrombosis, and DIC, with successful rivaroxaban treatment, adding to emerging data that oral factor Xa inhibitors are efficacious for treating HIT.

• Authors: Farheen Manji, Theodore E Warkentin, Jo-Ann I Sheppard, Adrienne Lee
• Journal: Platelets (Platelets) Vol. 31 Issue 1 Pg. 124-127 ( 2020) ISSN: 1369-1635 [Electronic] England
• PMID: 31397594 (Publication Type: Case Reports, Journal Article)

Chemical References

• Autoantibodies
• Immunoglobulin G
• Immunoglobulins, Intravenous
• Heparin
• Rivaroxaban
• Fondaparinux

Topics

• Aged
• Autoantibodies (immunology)
• Cross Reactions (immunology)
• Female
• Fondaparinux (adverse effects, immunology)
• Heparin (adverse effects, immunology)
• Humans
• Immunoglobulin G (immunology)
• Immunoglobulins, Intravenous (administration & dosage)
• Rivaroxaban (administration & dosage)
• Thrombocytopenia (diagnosis, drug therapy, etiology)
• Treatment Outcome
• Venous Thromboembolism (diagnosis, etiology)