Hemostasis and Coagulation Flashcards
What happens with excessive hemostasis?
Inappropriate clotting and/or thrombosis
What are the three stages of hemostasis?
Primary hemostasis
Secondary hemostasis
Clot retraction
What is in primary hemostasis?
vascular spasms (clamping down on damaged blood vessel)
Interaction b/w platelets and vessel
Formation of platelet plug (temp solution)
occurs in 3-7 minutes
Secondary hemostasis components
Formation of fibrin clot (coagulation)
Involves clotting factors
3-10 minutes
What happens during clot retraction?
Compression of fibrin to form firm clot
within a hour
what is the primary cell type in a clot?
Red blood corpuscle
Where are platelets (thrombocyte) produced from?
Megakaryocytes (mature cell in bone marrow) that flake apart to form these fragment cells
What do platelets adhere to?
Collagen exposed by trauma
then they degranulate
After degranulate- what granules are released by platelets?
Alpha granules and Dense granules
What is inside alpha granules?
Platelet thrombospondin, fibrinogen, fibronectin, von Willebrand factor, coagulation factors V & VIII
What is found in dense granules?
ADP, ATP, Serotonin
What causes the formation of thromboxane A2 (TxA2) and what does it do?
ADP + collagen;
TxA2 stimulates glycoprotein llb/llla receptor expression which promote platelet adhesion
what do platelets do in secondary hemostasis?
Catalyze interaction between activated coagulation factors
what blood coagulation factors are not plasma proteins?
Factor lll and calcium
All blood coagulation factors are synthesized by the
Liver (except part of factor VIII)
some synthesized by megakaryocytes and endothelial cells
Viktamin K helps for the synthesis and future activity of
Factors II, VII, IX, X, prot C, Prot S
What does Protein C do?
Inactivates Factors V and VIII- prevents clot formation
What does protein S do?
Stimulates with release of TPA (tissue plasminogen activator)
What is involved in intrinsic pathway of fibrin clot?
Factors XII, HMWK, prekallikrien, XI- formation of Xa (factor ten activated) and initiation of common pathway
Extrinsic pathway is triggered by…
Trauma of vascular wall (from outside)
What is the end result of intrinsic and extrinsic pathways?
Activation of Factor X and initiates of common final pathway
Factor Xa initiation the conversion of
Prothrombin to thrombin
What does thrombin do?
Cleaves fibrinogen to fibrin and activates factor XIII
What does factor XIII do?
forms insoluble clot- aid in clot retraction
What does fibrinolysis aid in?
Clot dissolution; initiated along with clot formation
What do the factors in Fibrinolysis result in ?
release of plasminogen activators (TPA)
Cleave plasminogen to plasmin
What does plasmin do?
DIgests fibrinogen and fibrin- inactivates factors V and VIII
What do you need to know to evaluate for evaluation of clotting factor disorders?
Family history, location, severity, duration, med history
Where are the most signs of clotting factor disorders?
Skin and mucous membranes (but they can happen in the internal organs as well)
how will individuals with clotting disorders often look?
Pale or jaundice
2 types of vascular disorders
Vascular purpura
Hereditary hemorrhagic Telangiectasia
What is vascular pupura?
When purpura presents on skin
Abnormality of vessels or tissues that support them
What are some types of vascular pupura
Allergic form, drug induced, abnormality of vessels or tissues that support them
What two types of vascular purpura are caused by Decreased and poor quality collagen and elastin
Ehlers-Danlos syndrome, osteogenesis imperfecta
Why does scurvy lead to vascular purpura?
Defective collagen due to lack of Vitamin C
Do vascular purpura lesions blanch?
No
In allergic vascular purpura- where do the lesions show up?
Proximal extremities (thigh and buttocks)
Where do you find hemorrhagic telangiectasia?
Any mucosal surface (most severe in lung, liver, brain); bright red or purple lesions on nose, lips. palate, etc.
What type disorder is hereditary hemorrhagic telangiectasia?
Autosomal dominant (also know as Osler-Weber-Rendu disease)
What is the most common clinical problem with hereditary hemorrhagic telangiectasia?
Epistaxis
What are 2 main platelet disorders?
Thrombocytopenia
Thrombocytosis
What is thrombocytopenia?
Lack of platelets
most common cause of generalized bleeding
What type of purpura is found in thrombocytopenia?
Idiopathic thrombocytopenic purpura (ITP)- immune mediated
What causes acute ITP?
An actue viral infection
What is chronic ITP caused by?
Probably autoimmune, found most often in women
Four mechanisms of thrombocytopenia
Decreased platelet production, decreased platelet survival, splenic sequestration, platelet dilution
What is thrombocytosis?
Excessive platelet numbers
What is thrombocytosis secondary to?
Hemorrhage, inflammatory disease, malignancy, infection, hemolysis, splenectomy
What is the transatory form of thrombocytosis?
Due to stress or exercise- there is a release of preformed platelets
What is the primary form of thrombocytosis?
Abnormal megakaryoctye proliferation
What are the complications with the primary form of thrombocytosis?
Hemorrhaging and thrombotic complications (create clots where they don’t belong- suck up all coagulation factors)
What are three inherited qualitative platelet disorders?
Bernard-Soulier syndrome
Von Willebrand disease
Glanzmann disease
(these are rare)
What are some causes of acquired platelet disorders?
Drug, with uremia, coexisting with hematolgic disease
What causes hemophilia A?
Factor VIII deficit
X-linked recessive (males)
(classic)
What causes hemophilia B?
Factor IX deficit
Classified by extend coagulation factor deficit
How is hemophilia diagnosed neonatally?
following circumcision
Following vitamin K injection (hematoma forms at stie)
Three classifications of hemophilia
<1 % severe case
1-5% normal- moderate
5-25% normal- mild
Biggest problem w/ hemophilia
Intracranial hemorrhage and serious bleeding episodes
With the mild form of hemophilia- when do symptoms occur?
When stressed (ex- surgery)
What is von Willebrand Disease caused by?
Autosomal disorder of factor VIII carrier protein- also includes platelet dysfunction
(affects both sexes)
What is the connection between von Wilebrand (VW) factor and Factor VIII
Normally circulate as a complex
VW stabilized factor VIII- normal platelet adherance
Disease VW- depression of factor VIII
When does Vitamin K Deficiency appear?
Newborns 48-72 hours to 6 months
more common in breast-fed infants
What factors are Vitamin K dependent?
II, VII, IX, X (meaning with vitamin K deficiency- will not be able to properly form a blot clot)
Where is Vit K absorbed?
Small intenstine;
Store in liver
Fat soluble
Why do bile problems possibly lead to vitamin K deficiency?
Bile problems- no fat dissolved- so no fat soluble vitamins are absorbed
What happens in DIC (disseminated intravascular coagulation)
Will have clotting in some parts of the body and bleeding in another part of the body (similar to not having enough platelets- but much more severe)
Where does chronic form of DIC show up?
Malignant cancer patients
What types of events are more common in chronic DIC?
Thromboses
What type of DIC is secondarily to other disorders?
Actue DIC
What is acrocyanosis? and where is it seen?
Cold, mottled, fingers, & toes
DIC (disseminated intravascular coagulation)
What does hepatic disease alter?
Function and production of factors
bile production and transport
