Pathophysiology Chapter 14: Hemostasis

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Questions and Answers

Describe the process of hemostasis.

Primary hemostasis: coagulation cascade activates clotting factors leading to blood clot formation. 2. Secondary hemostasis: formation of a fibrin clot through intrinsic and extrinsic pathways. 3. Final stage: clot retraction or fibrinolysis, where plasmin removes the blood clot.

What is the function of an anticoagulant?

Slows down the cascade (blood thinner) or speeds up fibrinolysis.

Describe how fibrinolysis works.

Factor XII activates thrombin release which turns plasminogen to plasmin, digesting fibrinogen and fibrin, and inactivates factors V and VIII.

What is hemostasis?

Hemostasis is the arrest of bleeding or prevention of blood loss after blood vessel injury. Signup and view all the answers

What are the consequences of inadequate hemostasis and excessive hemostasis?

Inadequate: bleeding. Excessive: clotting/thrombosis. Signup and view all the answers

Why are calcium and vitamin K important in hemostasis?

Calcium is essential for coagulation and vitamin K is necessary for the synthesis of clotting factors. Signup and view all the answers

What does a D-dimer test for?

Fibrin degradation protein and tests for fibrinolysis. Signup and view all the answers

What is the pathogenesis and treatment for hemophilia? What is the difference between types A and B?

Hemophilia is an inherited disorder causing excessive bleeding. A is factor VIII deficiency, and B is factor IX deficiency. Treatment for A includes cryoprecipitate or factor VII concentrate, and for B includes fresh frozen plasma or cryoprecipitate. Signup and view all the answers

What is the pathogenesis and treatment for von Willebrand disease?

An autosomal dominant disorder causing excessive bleeding due to a defective coagulation cascade. Treatment includes desmopressin, cryoprecipitate, and avoiding aspirin. Signup and view all the answers

What is the pathogenesis and treatment for DIC?

DIC involves blood clotting followed by bleeding, with decreased fibrinogen and platelet count. Treatment includes frozen plasma, packed RBCs, platelets, or heparin. Signup and view all the answers

What is the pathogenesis and treatment for hepatic disease?

Hepatic disease results in impaired absorption of vitamin K and decreased synthesis of clotting factors. Treatment involves administering vitamin K. Signup and view all the answers

What is the difference between blood thinners and blood busters?

Blood thinners dissolve blood clots, while blood busters break up larger blood clots. Signup and view all the answers

Study Notes

Hemostasis Process

Primary hemostasis involves the formation of a platelet plug and triggers the coagulation cascade within seconds after a vascular injury.
Secondary hemostasis leads to fibrin clot formation through intrinsic and extrinsic pathways, completed within minutes.
Final stage, clot retraction or fibrinolysis, dissolves the blood clot over two weeks, facilitated by plasmin.

Anticoagulant Function

Anticoagulants act as blood thinners, slowing down the coagulation cascade.
They can also speed up fibrinolysis, aiding in the dissolution of existing clots.

Fibrinolysis Mechanism

Factor XII and thrombin release plasminogen activators, converting plasminogen to plasmin.
Plasmin digests fibrinogen and fibrin, and inactivates factors V and VIII.
This process prevents the formation of new clots by removing existing ones.

Definition of Hemostasis

Hemostasis is the process of arresting bleeding and preventing blood loss following blood vessel injury.
It requires the cooperation of vessel walls, circulating platelets, plasma coagulation proteins, calcium, and vitamin K.

Consequences of Hemostasis Imbalance

Inadequate hemostasis leads to excessive bleeding.
Excessive hemostasis results in clotting and thrombosis.

Importance of Calcium and Vitamin K

Calcium is crucial for various steps in the coagulation cascade.
Vitamin K is essential for synthesizing certain coagulation factors.

D-dimer Test

The D-dimer test detects fibrin degradation products, indicating ongoing fibrinolysis.

Hemophilia Overview

Hemophilia is an X-linked recessive disorder mainly affecting males, causing excessive bleeding.
Hemophilia A involves factor VIII deficiency, while Hemophilia B (Christmas disease) features factor IX deficiency.
Key symptom is hemarthrosis (bleeding into the joints).
Treatment options: Factor VIII concentrates for Hemophilia A, fresh frozen plasma or cryoprecipitate for Hemophilia B.

Von Willebrand Disease

An autosomal dominant disorder causing excessive bleeding with equal prevalence in males and females.
Disrupts the coagulation cascade due to a deficiency of von Willebrand factor.
Treatment includes desmopressin, cryoprecipitate, and avoidance of aspirin.

Disseminated Intravascular Coagulation (DIC)

DIC starts with abnormal blood clot formation leading to bleeding; has a high fatality rate (~50%).
Characterized by decreased fibrinogen and platelet counts, increased bleeding time, and elevated PT/INR/aPTT levels.
Elevated D-dimer indicates ongoing fibrinolysis.
Treatment includes frozen plasma, packed RBCs, platelets, cryoprecipitate, and heparin.

Hepatic Disease and Coagulation

Hepatic disease affects the absorption of vitamin K, leading to decreased synthesis of coagulation factors.
Results in the inability to remove activated clotting factors.
Treatment involves administering vitamin K.

Blood Thinners vs. Thrombolytics

Blood thinners are designed to prevent blood clot formation.
Blood busters (thrombolytics) break down existing blood clots and are typically used for larger clots.

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Description

Dive into Chapter 14 of Pathophysiology as we explore the intricate processes involved in hemostasis and blood coagulation. Understand primary and secondary hemostasis, and how the body effectively responds to vascular injury through clot formation. Test your knowledge with helpful flashcards!