American Society of Hirudotherapy

Delayed-onset heparin-induced thrombocytopenia

Case report published in Ann Emerg Med (2005)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Case reportDrug DevelopmentClinical TrialsSmythe MA et al. · Annals of emergency medicine, 2005

Abstract

Delayed-onset heparin-induced thrombocytopenia is a syndrome in which thrombocytopenia and thrombosis begin several days after heparin discontinuation. Delayed-onset heparin-induced thrombocytopenia is caused by immunoglobulin G antibodies that are reactive against the heparin-platelet factor 4 complex in the absence of circulating heparin. We describe 2 patients with delayed-onset heparin-induced thrombocytopenia who presented to the emergency department. An 88-year-old man and a 62-year-old man experienced thrombocytopenia and thrombosis 9 or more days after heparin cessation and demonstrated a further decrease in platelet count on reexposure to heparin. Delayed-onset heparin-induced thrombocytopenia should be included in the differential diagnosis of a patient with recent heparin exposure who presents with thrombosis or thrombocytopenia.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Publication typeCase ReportsJournal Article
Indexed MeSH termsAgedAged, 80 and overAnticoagulantsEmergency Service, HospitalHeparinHirudinsHumansMaleMiddle AgedPlatelet Factor 4Recombinant ProteinsThrombocytopenia

Summary

Two cases of delayed-onset HIT presenting >9 days after heparin discontinuation with thrombocytopenia and thrombosis, illustrating need for emergency diagnostic awareness.

Why This Matters for Hirudotherapy

This article presents two cases of delayed-onset heparin-induced thrombocytopenia, describing an 88-year-old man and a 62-year-old man who developed thrombocytopenia and thrombosis nine or more days after heparin cessation, with further platelet decline on reexposure. The abstract explains the syndrome as mediated by IgG antibodies reactive against the heparin–platelet factor 4 complex even in the absence of circulating heparin, and emphasizes the importance of including delayed-onset HIT in differential diagnosis. The abstract itself does not mention hirudin, lepirudin, leeches, or any anticoagulant therapy, so no direct relevance to hirudotherapy or the leech secretome can be established from the text. The scope is diagnostic recognition based on two case reports, with no treatment detail.

Citation

Delayed-onset heparin-induced thrombocytopenia.

Smythe MA et al. · Annals of emergency medicine, 2005

DOI

Added to ASH library: May 27, 2026 · Site last updated: June 18, 2026

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