Coagulation Factors and Hemostasis

Introduction

• Lecture by the "Coasters Perfectionist" on bleeding and coagulation.
• Video number 96 in a series.
• Focus on coagulation factors, their names, numbers, and functions.
• Importance of understanding the coagulation cascade and previous videos recommended for background.

Hemostasis Overview

• Hemostasis has several steps; discussion focuses on step 3: coagulation (secondary hemostasis).
• Distinction between primary and secondary hemostasis:
  • Primary Hemostasis: Platelet plug formation, mucocutaneous bleeding.
  • Secondary Hemostasis: Coagulation cascade, fibrin clot formation, deep bleeding.

Coagulation Tests

• PT (Prothrombin Time) and PTT (Partial Thromboplastin Time) are critical tests for secondary hemostasis.
• Older test: Coagulation time or clotting time (less specific).

Key Coagulation Factors

• Total of 12 factors, though numbered up to 13, since Factor 6 does not exist.
• Factor 13 is crucial for stabilizing fibrin.
• Factors are proteins, specifically beta-globulins, sourced from the liver.

Coagulation Cascade

• Begins with vasoconstriction and primary hemostasis (platelet adhesion, activation, aggregation).
• Coagulation cascade: Converts fibrinogen to fibrin, forming a stable fibrin meshwork.
• Two main pathways to activate Factor 10:
  • Extrinsic Pathway: External factors like tissue factor activate Factor 7.
  • Intrinsic Pathway: Internal factors like subendothelial collagen activate Factors 12, 11, 9, and 8.

Factor Activation

• Fibrinogen (Factor 1) to Fibrin via Thrombin (Factor 2).
• Prothrombin Complex: Factors 5 and 10, along with calcium and phospholipids.
• Stabilization by Factor 13 to prevent late rebleeding.

Hemophilia and Factor Deficiencies

• Hemophilia types: A (Factor 8), B (Factor 9), C (Factor 11).
• Factor deficiencies lead to specific bleeding disorders.

Factors and Functions

• Factor 1 (Fibrinogen): Polymerizes to form fibrin.
• Factor 3 (Tissue Factor): Activates Factor 7.
• Factor 4 (Calcium): Essential mineral in the cascade.
• Factor 5 (Labile Factor): Cofactor in the cascade.
• Factor 7 (Stable Factor): Converts Factor 10 into active form.
• Factor 8 (Antihemophilic Factor): Cofactor, linked to Hemophilia A.
• Factor 9 (Christmas Factor): Linked to Hemophilia B.
• Factor 10 (Stuart-Prower Factor): A serine protease.
• Factor 11 (PTA): Precursor to thrombin.
• Factor 12 (Hageman Factor): Initiates intrinsic pathway.
• Factor 13 (Fibrin-stabilizing Factor): Stabilizes fibrin mesh.

Diseases and Conditions

• A-fibrinogenemia: Lack of fibrinogen.
• Hypoprothrombinemia: Deficiency in prothrombin.
• Parahemophilia: Linked to Factor 5 deficiency.
• Hemophilia Types: A, B, C (linked to Factors 8, 9, 11 respectively).
• Factor 10 Deficiency: Known as Stuart-Prower Deficiency.
• Factor 12 Deficiency: Known as Hageman Deficiency.
• Factor 13 Deficiency: Leads to unstable fibrin clots.

Further Study and Resources

• Mention of website with additional hematology cases and courses.
• Upcoming discussions on groups of coagulation factors.

Conclusion

• Encouragement to subscribe, support, and engage with further resources.
• Promotional message for educational content and website.