Disorders of Hemostasis

Clinical Characteristics of Bleeding Disorders
Feature Platelet/vascular Defect Coagulation Defect
Site Skin, mucous membranes Deep in soft tissues (muscles, joints)
Lesions Petechiae, ecchymoses Hemarthroses, hematomas
Bleeding After minor cuts: yes
After surgery: immediate, mild
After minor cuts: unusual
After surgery: delayed, severe
Figure 5-3 Approach to abnormal hemostasis (NEJM 2014;370:847)
Figure 5-4 Coagulation cascade (NEJM 2008;359:938)

Purpura (nonblanching purple/red lesions due to extravasation of RBCs into dermis)

  • Nonpalpable (macular; ≤3 mm in diameter = petechiae; >3 mm = ecchymoses)
    • platelet disorder: thrombocytopenia, defect in platelet fxn
    • thromboemboli: DIC, cholesterol or fat emboli