Definition of a critical bleed in patients with immune thrombocytopenia: Communication from the ISTH SSC Subcommittee on Platelet Immunology

Emily Sirotich, Gordon Guyatt, Caroline Gabe, Zhikang Ye, Carolyn E. Beck, Vicky Breakey, Nichola Cooper, Adam Cuker, Jay Charness, Kerstin de Wit, Jennifer DiRaimo, Steven G. Fein, Rachael F. Grace, Ziauddin Hassan, Erin Jamula, Matthew Kang, Charles F. Manski, Clare O'Connor, Menaka Pai, Dale PaynterStephen C. Porter, Barbara Pruitt, Gail Strachan, Kathryn E. Webert, Justin W. Yan, John G. Kelton, Tamam Bakchoul, Donald M. Arnold*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Background: Immune thrombocytopenia (ITP) is an autoimmune disease characterized by low platelet counts and increased risk of bleeding. In preparation for an upcoming guideline, the ITP Emergency Management Guideline Panel, including clinical experts in hematology, emergency medicine, research methodology, and patient representatives, identified the need for a standardized definition of a critical ITP bleed. The goal of the definition was to distinguish critical bleeds from bleeds that may not require urgent treatment, typically in the context of severe thrombocytopenia. Methods: The panel met in person and virtually to achieve consensus on the criteria for critical bleeding events among patients with ITP. Existing ITP bleeding scores and published definitions of major bleeds in patients receiving anticoagulation informed the definition of a critical ITP bleed. The Platelet Immunology Scientific Standardization Committee (SSC) of the International Society on Thrombosis and Haemostasis endorsed the definition. Results: A critical ITP bleed was defined as: (a) a bleed in a critical anatomical site including intracranial, intraspinal, intraocular, retroperitoneal, pericardial, or intramuscular with compartment syndrome; or (2) an ongoing bleed that results in hemodynamic instability or respiratory compromise. Conclusion: The definition of a critical ITP bleed was developed by the ITP Emergency Management Guideline Panel and endorsed by the Platelet Immunology SSC. It incorporates both anatomic and physiologic risk and pertains to patients with confirmed or suspected ITP who typically have severe thrombocytopenia (platelet count below 20 × 109/L).

Original languageEnglish (US)
Pages (from-to)2082-2088
Number of pages7
JournalJournal of Thrombosis and Haemostasis
Issue number8
StatePublished - Aug 2021


  • blood platelets
  • emergencies
  • hemorrhage
  • idiopathic
  • purpura
  • thrombocytopenic

ASJC Scopus subject areas

  • Hematology


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