Chapter 14: Clinical Disturbances of Blood Coagulation 2 Flashcards
What does deficiencies of one or more coagulation factors often cause?
Hematomas
Large area of hemorrhage
hematoma
True or false: Deficiencies of phase I coagulation factors are relatively rare and are usually hereditary.
True
Coagulation factors of which phase are deficient in people with Hemophilia A, Hemophilia B, and von Willebrand’s disease?
Phase I
What coagulation factors are people with Hemophilia A and B deficient in? What causes this deficiency?
Phase 1; it is hereditary
What coagulation factors are people with von Willebrand’s disease deficient in?
Phase 1 (von Willebrand Factor)
What is the most common bleeding disorder? What causes it?
von Willebrand Disease; deficiency of von Willebrand Factor
Which conditions caused by deficiencies of Phase I coagulation factors are relatively common (exceptions to the rule that most coagulation factor deficiencies are rare):
1) Hemophilia A
2) Hemophilia B
3) von Willebrand Factor
Which phase of blood coagulation are Factors IX and X part of?
Phase I
What is the most common bleeding disorder?
von Willebrand’s Disease
What is the most common clotting disorder?
Thrombocytopenia
What type of hereditary disease is hemophilia?
X-linked recessive
What is the most common hereditary bleeding disease?
Hemophilia
What are the symptoms of hemophilia?
Episodic bleeding in joints and internal organs after minor injury; potentially intracranial bleeds.
True or false: Hemophilia affects only females.
False; it affects only males, unless an affected male and carrier female are parents.
A decrease in which coagulation factor causes Hemophilia A? Which phase of coagulation is this factor part of?
factor VIII (anti-hemophilic factor); Phase I
A decrease in which coagulation factor causes Hemophilia B? Which phase of coagulation is this factor part of?
factor IX (Christmas factor)
A decrease in which coagulation factor causes von Willebrand’s Disease? Which role does this factor play?
vWF; required by platelets to adhere to the vessel wall at the injury site.
How does vWF work?
Adheres to a damaged wall and forms a lattice framework, allowing platelets and coagulation factors to adhere, interact, and form a clot.
Besides vWF, what other factor do von Willebrand Disease patients have low levels of in their circulation?
factor VIII (they make enough of it, but b/c of the low vWF, cannot bind and maintain normal levels in circulation).
How can patients with Hemophilia or von Willebrand’s Disease be treated?
With factor concentrates
True or false: Phase I coagulation disturbances are usually hereditary.
True
True or false: Phase II hereditary disturbances are usually hereditary.
False; usually acquired.
What are the two causes of Phase 2 coagulation disturbances?
1) Prothrombin deficiency
2) Deficiency of factors required to convert prothrombin to thrombin.
Where are the factors required to convert prothrombin to thrombin located?
In the liver
Which key vitamin is required for the synthesis of most phase II coagulation factors?
Vitamin K (fat soluble)
What is required for vitamin K absorption?
Bile
Where does most of our vitamin K come from?
Mostly made by intestinal bacteria; also from green, leafy veggies
What can phase 2 disturbances be caused by?
1) Drugs that reduce vit K synthesis (e.g., anticoagulants)
2) Inadequate bacterial synthesis of vit K (e.g., b/c of prolonged antibiotic use)
3) Inadequate absorption of vit K (blockage of common bile duct)
4) Severe liver disease (impairs synthesis of coagulation factors)
What are anticoagulant drugs that inhibit of vitamin K-dependent factors used for?
To decrease the risk of clotting in certain patients
Why might prolonged antibiotic use cause a phase II clotting disorder?
It could eradicate the intestinal bacteria needed for the synthesis of vitamin K.
True or false: Newborns lack gut bacteria.
True
What does DIC stand for? What causes it?
Disseminated (widespread) Intravascular Coagulation; caused by products being released into the circulation that have thromboplastic activity (i.e., activate the coagulation mechanism)
Activate the coagulation mechanism
thromboplastic
When might you see DIC (disseminated intravascular coagulation)?
1) Disease associated with shock or tissue necrosis.
2) Sepsis (overwhelming bacterial infection)
3) Amniotic fluid entering circulation postpartum
4) Other causes of tissue necrosis.
formation of a blood clot that obstructs blood flow in a vessel
thrombosis
An abnormal bleeding state that leads to rapid and widespread activation of blood coagulation.
Disseminated Intravascular Coagulation Syndrome (Consumption Coagulopathy)
What is the net result of DIC?
Widespread hemorrhaging
Why does DIC result in hemorrhaging?
1) Platelets and plasma coagulation factors are consumed quickly, so their blood levels drop.
2) Body activates fibrinolysin system, leading to fibrin degradation products that further inhibit coagulation.
What is the comparative frequency of occurrence of platelet problems, coagulation disturbances, or DIC (disseminated intravascular coagulation)?
Platelet problems > Coagulation disturbances > DIC
