Chapter 22: Disorders of Hemostasis Flashcards
Why should blood clot?
Hemostasis is designed to maintain the integrity of the vascular component
What are 5 stages of hemostasis?
- Vessel spasms
2.Formation of the platelet plug - Blood coagulation or development of an insoluble fibrin clot
4.Clot retraction
5.Clot dissolution
**Categories of Disorders of hemostasis
What is thrombosis ?
Blood clot inappropriately forms within veins or arteries
**Categories of Disorders of hemostasis
What is bleeding?
Blood fails to clot and result in excessive bleeding
What is vascular constriction?
-Spasms which is transient
-Last minutes to hours
-Initiated by endothelial injury
What is platelet plug formation?
Adhesion and aggregation of platelets
1. Platelets are attracted to damaged vessel wall
2.Attraction is activated by subendothial tissue
3.Platelet will change from smooth disks to spiny spheres so they are able to clump together
4. They will expose glycoprotein receptors to their surfaces
What are requirements for blood to clotting process?
-Presence of platelets produces by bone marrow
-Von Willebred factor which is generated by the vessle endothelium
-Vitamin K as a clotting factor. Vitamin K is synthesized in liver. If liver isn’t working you won’t have enough vitamin K and will lead you to liver disorder
What is clot retraction and dissolution?
-Other significant factors that happen with homeostasis
-Process that involves interaction of various factors so that clots can get smaller or dissolve
-It is an attempt to reduce the risk of thrombus formation
What are intrinsic and extrinsic coagulation pathways?
-Both end up in the same reaction which is clotting of the blood
Factors required for coagulation to happen
-Calcium factors x &V, and platelets phospholipids will combine to form prothrombin activator
-The prothrombin activator turns into prothrombin then intro thrombin
-This interaction cause the conversion of fibrinogen into fibrin create a insoluble blood clot
What is the regulation of blood coagulation?
-Regulated by Antithrombin lll. Inactivates coagulation factors and neutralizes thrombin
-Regulate by Protein C, acts as a anticoagulant by inactivating factors V and Vll
Check and balance so the blood doesn’t over clot or underclot. Alot of clot formation can cause occusion in vessels cause ischemia and underclotting could cause excessive bleeding
***Regulation of bLood coagulation
What are other factors responsible for blood coagulation?
-Protein S, accelerates the action of protein
-Plasmin breaks down fibrin into fibrin degradation products and act as anticoagulants
What are Conditions that create increased platelet function/ hyper coagulability:
-Atherosclerosis
-Diabetes mellitus
-Smoking
-Elevated blood lipod and cholesterol levels
-Increase platelet activity
What are conditions that cause accelerated activity of the coagulation system?
-Pregnancy, and the puerperium
-Use of oral contraceptives
-Post surgical state
-Immobility
-Congestive heart failure
-Malignant disease
***Hyper coagulability states
What does hyper coagulability put you at risk for?
Increase risk of clot or thrombus formation in the arterial or venous circulations
***Hyper coagulability states
What happens in the arterial system at with hypercoagulability
Arterial system at risk is associated with the tuburlance that whirls blood around with force of arterial pressure which leed to platlet adherance
***Hyper coagulability states
What happens in the venous system at with hypercoagulability
In the venous system it’s related to stasis/slowing down of blood and increased concentration of coagulation factors
What can causes bleeding?
-Decrease number of circulating platlets
-Impaired platelet functions
occurs in small vessels and characterized by petechiae and purpura
How does hypercoagualation and what does it cause?
Hypercoagubility happens due to increase platelet function, resulting in platelet adhesion, formation of platelet clot, and disruption of blood flow
-This can be caused by disturbances in flow, endothelial damage, and increased sensitive of platelets to factors that cause adhesiveness and aggregation
What is atherosclerotic plaque and platelet?
-Atherosclerotic plaques disturb blood flow, causing endothelial damage and promoting platelet to to stick together
-Platelets that stick to the vessel wall release growth factors, which cause proliferation of smooth muscle and contributes tot he development of atherosclerosis
-Smoking, elevated levels of blood lipids and cholesterol, hemodynamics, and diabetes mellitus aid to vessel damage, platlet adherence and eventual thrombosis
What is platelets defects?
-Thrombocytopenia
-Impaired platelet function
What is thrombocytopenia?
A low platelet count that
Results from a
-decrease in platelets production or
-sequestration of platelets in the stream(Like hoarding)
-Platelets not surviving as long as thy should
What is Impaired platelet function?
Bleeding resulting from platelet deficiency
What are signs and symptoms of thrombocytopenia?
-Bleeding in mucous membranes
likeNose, mouth, gastrointestinal tract, uterine cavity
-Commonly occurs in small vessels
-Seen mostly in the conditions with platelet deficiency
-You will also see purpura which is purple areas of bruising
What Vitamin is needed for coagulation
-Vitamin K is essential for clotting factors
- If there is something wrong with the liver and it’s not producing or synthesizing enough vitamin K that will result in abnormal bleeding
What are vascular disorders that can cause bleeding ?
-Hemorrhages telangiectasia
-Vitamin C deficiency
-Cushing disease
-Senile purpura
**Vascular disorders that cause bleeding
What is hemorrhagic telangiectasia?
An uncommon autosomal disorder characterized by thin-walled, dilated capillaries and arterioles
**Vascular disorders that cause bleeding
how does Vitamin C deficiency contribute to bleeding?
-Results in poor collagen synthesis and failure of the endothelial cells to be cemented together properly will cause a fragile/weak wall
**Vascular disorders that cause bleeding
How does Cushing disease contribute to bleeding disorders?
Causes protein wasting and loss of vessel tissue support due to excess cortisol
**Vascular disorders that cause bleeding
Why does sensile purpura cause bleeding disordeR?
This caused bruising in elderly alduts which is caused by the aging process
What is disseminated intravascular coagulation?
-Life threatening
-Cause by systemic activation of blood coagulation
-Leads to multi organ dysfunction
-The coagulation is activation and moves all over the body so micro-clots end up all over the body which ends up in small and large vessels
What are conditions that can cause people to have disseminated intravascular coagulation?
-Obstetric condiitons
-cancers
-Infections
-Shock
-Trauma or surgery
-Hematologic conditions
