Hemorrhage and Hemostasis
Start with the big picture
Hemorrhage is the escape of blood from vessels into tissues or body cavities. Its forms range from petechiae and purpura to ecchymoses, hematomas, and cavity or joint bleeding. The size and pattern of bleeding can offer clues to its cause: platelet problems commonly produce petechiae and mucocutaneous bleeding, while coagulation factor deficiencies may cause deep tissue or joint bleeding. Hemostasis proceeds through primary platelet-plug formation and secondary fibrin clot formation, balanced by antithrombotic mechanisms and fibrinolysis. Laboratory tests assess different parts of this system, including platelet function and the intrinsic, extrinsic, and common coagulation pathways. The topic also surveys thrombocytopenia, von Willebrand disease, hemophilia, DIC, vitamin K deficiency, and thrombosis, including Virchow’s triad and thrombophilias.
What you'll learn
- Distinguish major forms of hemorrhage and relate their patterns to clinical clues.
- Outline primary and secondary hemostasis, antithrombotic regulation, and fibrinolysis.
- Identify what PT, aPTT, and platelet-function assessments evaluate.
- Compare the characteristic bleeding patterns of thrombocytopenia, von Willebrand disease, and hemophilia.
- Describe the lesson’s framework for DIC, thrombosis, Virchow’s triad, and thrombophilias.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
