Chapter 12: disorders of hemostasis Flashcards
(30 cards)
What are the two forms of hypercoagulability states?
conditions that increase platelet function
conditions that accelerate the coagulation system
What are the 4 types of bleeding disorders?
1) thrombocytopenia
2) coagulation disorders
3) vascular causes
4) disseminated intravascular coagulation
What is hemostasis?
stoppage of blood flow to prevent loss and hemorrhage
What are the two types of abnormal hemostasis?
inappropriate clotting (hypercoagulability states)
insufficient clotting (bleeding disorders)
What secretes the von Willebrand factor? What does this factor do?
It is secreted by endothelial cells
VWF allows platelets to adhere to the exposed collagen fibers
What are the 5 stages of hemostasis?
1) Vessel spasm
- to initially constrict blood flow
2) Platelet plug forms
- adhesion by von Willebrand factor
3) Blood coagulation
- via coagulation cascade
4) Clot retraction
- actin and myosin in platelets
5) clot lysis
- converting of plasminogen to plasmin which breaks down the clot
What organ synthesizes most coagulation factors?
the liver
What two minerals are coagulation factors dependent on?
Ca for end intrinsic and the extrinsic pathway
K for intrinisic
What is fibrinolysis? Describe what is involved
the process of clot dissolution.
Plasminogen circulates in the blood, gets converted to plasmin which then digests the fibrin
What are the two ways that you can have hypercoaguability states?
inc platelets (thrombocytosis)
Inc clotting activity
How might you get increased platelets?
reactivie disorders (iron-def anemia, splenctommy, Ca)
MYELOPROLIFERATIVE disorders:
acquired genetic anomaly
polycythemia vera
What are the 4 categories of conditions that would give you a hypercoagulability state?
INHERITED or ACQUIRED disorders altering coagulation factors
ENDOTHELIAL DMG
DEC ANTI COAGULATION FACTORS
Give some examples of acquired increased clotting activity.
bed rest
immobility
meds
malignancy
Explain why endothelial dmg makes coagulation easier. what are some things that can cause this?
it makes platelet adhesion easier
- artherosclerosis
- smoking
What are the two categories that can cause thrombocytopenia?
DEC PRODUCTION
INC destruction
IMPAIRED FUNCTION
What are some things that can cause dec production of thrombocytes?
anemia
bone marrow malignancy/depression
What are a few things that can cause inc destruction of thrombocytes?
antiplatelet antibodies
drug induced
immune/idiopathic thrombocytopenic purpura (ITP)
What is idiopathic thrombocytopenic purpura (ITP)
an autoimmune disorder that destroys platelets
may be primary or secondary
more common in children
What are some things that can cause impaired function resulting in thrombocytopenia?
inherited deficiencies of VWF
acquired factors: disease, meds (ASA/NSAIDS)
What are the three signs of thrombocytopenia?
bruising/bleeding of skin and mucous membrane of nose, mouth, GI tract, uterine cavity
PURPURA (large but spotty purple)
PETECHIAE (tiny little dots)
List three inherited coagulation disorders
von Willebrand disease
hemophilia A (deficiency of VIII)
hemophilia B (deficiency of IX) - less common
give an example of an acquired coagulation disorder
vit k deficiency
Describe what von willebrand disease is
deficiency in vWF (usually inherited)
- platelets cannot adhere properly, can result in spont bleeding
has normal platelet count
Describe what hemophelia A is
X - linked that primarily affects males
factor VIII deficiency
Bleeding in soft tissues, can have joint bleeding when child begins to walk which leads to inflammation, pain, and swelling
