Week 3b Hemostasis Flashcards
what are the 3 types of anti platelets?
aspirin, clopidogrel (plavix) and glycoprotein
what are the 2 main adverse effects of heparin?
abnormal bleeding and heparin induced thrombocytopenia
Heparin induced thrombocytopenia is caused by?
abnormal antibodies that activate platelets, causing clots to form and depleting platelet counts in the blood
LMWH can cause which type of negative response?
skin necrosis
what are 2 examples of direct thrombin/Xa inhibitors
dabigatran and rivaroxaban
what are 3 adverse effects of warfarin (Coumadin)
microembolism, osteoporosis and abnormal bleeding
what must you monitor when a patient is receiving Coumadin (warfarin)?
INR
thrombolytics are?
the only drugs which destroy existing clots
what is an example of a thrombolytic?
tissue plasminogen activator (tPA)
what is an uncommon condition which is precipitated by tissue injury and associated with hyper coagulation and hemorrhage?
Disseminated Intravascular Coagulation
What are 3 types of coagulation defects?
1) Von Willebrand Disease
2) Hemophilia A
3) Hemophilia B
What are 4 types of vascular disorders that cause bleeding?
1) Hemmorhagic telangiectasia
2) Vit C deficiency (scurvy)
3) Cushing disease
4) Senile purpura
Antifybrinolytics are used for?
preventing the breakdown of fibrin/existing clots, thereby preventing excessive bleeding
when are antifibrinolytics most commonly used?
after surgery to prevent bleeding
What is an example of an antifibrinolytic?
Aminocaproic acid (Amicar)
Vitamin K is required for?
synthesis of clotting factors by hepatocytes (factor II (prothrombin), VII IX and X)
What is calcium’s role in coagulation?
needed for factor IV
Vitamin K
a fat soluble vitamin synthesized by intestinal bacteria that is an essential cofactor for the synthesis of clotting factors
Causes of vitamin K deficiency
- disorders that reduce fat absorption
- high alcohol consumption
- anticonvulsants and some antibiotics
- use of Coumadin anticoagulants
- prolonged use of antibiotics
Why can vitamin K deficiency occur in newborns?
- insufficient gut bacteria
- poor placental transport of vitamin K
- Low prothrombin synthetic capacity of neonatal liver
LMWHs and rivaroxaban act on?
Active factor X
Heparin acts on
thrombin
Wafarin acts on
Prothrombin (factor II)
What are some conditions that create increased platelet function?
- atherosclerosis
- DM
- Smoking
- elevated blood lipid and cholesterol levels
- increased platelet levels
what are some conditions that cause accelerated activity of the coagulation system?
- pregnancy
- use of oral contraceptives
- post surgical state
- sepsis/systemic inflammation
- injury
- CHF
- malignant diseases
- stress
arterial thrombi are associated with?
conditions that produce turbulent blood flow and platelet adherence
Venous thrombi are associated with?
conditions that cause stasis of blood flow with increased concentrations of coagulation factors
throbocytosis
elevations in platelet count
erythromelagia
painful throbbing and burning of the fingers cause by occlusion of the arteries and platelet aggregates
Tx for hypercoagubility due to increased platelet function
platelet lowering drugs such as hydroxyurea in high risk cases and aspirin as an adjunct
what carries a high risk for adverse pregnancy outcomes?
hypercoagubility due to increased clotting activity
antiphospholipid syndrome
a condition associated with autoantibodies directed against protein-binding phospholipids that result in increased coagulation activity
what factors predisposes the vessel to damage, platelet adherence and eventual thrombosis?
smoking, elevated levels of blood lipids and cholesterol, hemodynamic stress and diabetes mellitus
what is the MoA of aspirin?
blocks thromboxane A2 in degranulation as well as COX 1 inhibition resulting in decreased platelet aggregation
what is the MoA of clopidogrel
blocks ADP receptors in platelets, inhibiting activation and aggregation, thereby extending clotting times
Therapeutic effects and uses of clopidogrel
- reduce risk of CVA/MI
- Reduces thrombolytic events post CVA/MI
- Prevent DVT
- Prevent thrombi formation in unstable angina/coronary stents
What are some adverse effects of Clopidogrel (plavix)?
- headache, dizziness
- flu-like syndrome
- diarrhea
- bruising
- upper respiratory tract infection
- rash, pruritus
Serious adverse effect of clopidogrel
abnormal bleeding
Indications of Glycoprotein (abciximab)
- acute coronary syndrome
- percutaneous coronary intervention
MoA of glycoprotein (abciximab)
prevents platelet activation and aggregation by blocking glycoprotein
adverse effects of glycoprotein
- back and chest pain
- hypotension
- abnormal bleeding
what can be a sign of internal bleeding?
hypotension
What is the therapeutic margin of PTT?
usually 2x the normal value
therapeutic effects and uses of heparin
- acute thromboembolic disorders including DVT, PE, unstable angina and evolving MI
- prophylaxis for clotting (orthopedics)
what are some of the advantages of direct thrombin inhibitors/Xa inhibitors?
- PO
- high efficacy of preventing stroke
- convenient
- minor drug and food interactions
- predictable PK and PD
- rapid onset and offset
- short-half life
- no need for lab testing
what is a risk of immune thrombocytopenia purpura?
intracranial hemorrhage
what are the therapeutic effects and uses of Amicar?
- aplastic anemia
- hepatic cirrhosis
- postoperative cardiac surgery
von willebrand disorder is a disorder of decreased…?
platelet adhesion
petechiae and purpura are common manifestations of?
thrombocytopenia
- X-linked recessive disorder (primarily males).
- Mutation in the factor VIII gene.
bleeding occurs in soft tissues, the gastrointestinal tract, and the hip, knee, elbow, and ankle joints. - Spontaneous joint bleeding usually begins when a child begins to walk.
- Tx: factor VIII products
Hemophilia A
- deficiency of factor IX,
- It is genetically and clinically similar to hemophilia A.
hemophilia B
- Spontaneous bleeding (nose, mouth, gastrointestinal tract),
- excessive menstrual flow,
- prolonged bleeding time with normal platelet count.
- Tx: VIII/vWF concentrate
Von Willebrand disease
Von Willebrand disease is caused by?
Deficiency of factor VIII and poor platelet function
