Hematology: Protein C Deficiency

Definition

• Definition: Deficiency in Protein C (< 70-75%)
  • Normally Activated Protein C (aPC) Inhibits Factors Va & VIIIa
• Diagnosis Often Difficult Because Other Pathologies Can Create an Acquired Protein C Deficiency
• Prevalence: 0.2-0.3%

Effects

• Increased Risk for VTE (Odds Ratio 7)
• May Have an Increased Risk for Warfarin-Induced Skin Necrosis (Rare)

Diagnosis

• Diagnosis: Functional Coagulation Testing
• Indication for Testing:
  • Thrombophilic Family (Strong Family History of VTE)
  • VTE at a Young Age (< 50 Years)
  • VTE in an Unusually Location (Portal/Hepatic/Mesenteric/Cerebral)
  • Recurrent VTE
  • Warfarin-Induced Skin Necrosis
• In General, If Testing Should Also Test for Other Inherited Thrombophilias
  • *See Hematology & Oncology: Factor V Leiden
  • *See Hematology & Oncology: Prothrombin G20210A
  • *See Hematology & Oncology: Antithrombin-III Deficiency
  • *See Hematology & Oncology: Protein S Deficiency

Management

• VTE Treatment: Anticoagulation – Similar to the General Population
• VTE Prevention: Generally Can Avoid Routine Chronic Anticoagulation Unless Otherwise Indicated or High-Risk