Definition:
Hemorrhagic diathesis refers to an abnormal tendency to bleed, due to disorders affecting hemostasis (blood clotting), including platelet function, coagulation pathways, or vascular integrity.
It is a clinical manifestation rather than a single disease, and reflects hypocoagulability, resulting from acquired or inherited causes.
Etiology:
A. Acquired Causes:
- Liver disease (most common):
- ↓ Synthesis of coagulation factors
- ↓ Vitamin K-dependent factors (II, VII, IX, X)
- Thrombocytopenia (due to hypersplenism from portal hypertension)
- Abnormal fibrinogen or platelet function
- May result in DIC (disseminated intravascular coagulation)
- Vitamin K deficiency:
- Malabsorption, prolonged antibiotic use, or warfarin therapy
- Autoimmune causes:
- ITP (Immune thrombocytopenic purpura): Autoantibodies destroy platelets
- Surgery / Malignancy-associated fibrinolysis:
- Tumors (prostate, pancreas, breast, uterus) → release of plasminogen activators
- Antiphospholipid syndrome:
- Lupus anticoagulant paradoxically causes thrombosis but prolongs aPTT
B. Inherited Causes:
- Hemophilia A (Factor VIII deficiency)
- Hemophilia B (Factor IX deficiency)
- Von Willebrand Disease (vWF defect → affects platelet adhesion and factor VIII stability)