Pocket Medicine

HEMATOLOGY-ONCOLOGY

DISORDERS OF HEMOSTASIS

Figure 5-3 Approach to abnormal hemostasis

Figure 5-4 Coagulation Cascade

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, TTP, cholesterol or fat emboli

trauma or vascular fragility: amyloidosis, Ehlers-Danlos, scurvy

•   Palpable (papular); vasculitis: leukocytoclastic, HSP, PAN, RMSF;

infectious emboli: meningococcemia, bacterial endocarditis

•   Purpura fulminans (aka retiform purpura): purpura + hypotension + DIC; typically due to infxn/sepsis, protein C or S deficiency or APS (see section on DIC)