Hematology Flashcards
What is secondary hemostasis?
Formation of the fibrinogen clot I.e. factors
- Extrinsic
- Intrinsic
what is primary hemostasis?
Platelets binding
- Adhesion
- Activation
- Aggregation
What is adhesion of primary hemostasis?
i.e. How do platelets bind to broken down endothelium?
Von wilibrands factor (vWF) on the endothelium binds to glyc Ib on platelets
What are two diseases associated with adhesion problems of platelets?
Bernard Soliers dz ( malfunctioning glyc Ib)
Von Wilibrands disease (malfunctioning vWF)
In primary hemostasis, once adhesion has occurred how are platelets activated?
They express thromboxane A2 (TXA2) and ADP which in turn activates other platelets.
Two drugs that inhibit activation are aspirin (blocks TXA2) and Plavix (inhibits ADP)
In primary hemostasis once platelets are adhesive and activated they need to aggregate. How does this occur?
Platelets bind to each other via glyc IIb/ IIIa, and covered with fibrinogen.
Abciximab inhibits this and it’s malfunctioning in Glanzmans Thrombasthenia
In secondary hemostasis what are the three pathways?
Common: 1,5,2,10
Extrinsic: 7
Intrinsic: the rest
What’s the name of factor 2
Thrombin
What’s the name of factor 1
Fibrinogen
Factor 1 (fibrinogen) -> Factor 1a (Fibrin). What breaks down fibrin to D-dimers?
Plasmin. Which is activated from plasminogen by tPA
What factors does Coumadin inhibit?
2,7,9,10
What drugs inhibit factor 10a?
Apixiban,
Rivaroxiban (xarelto)
What drugs inhibit thrombin (Factor 2)?
Dabigatran,
Lepirudin,
Argatroban
What is the mechanism of action of heparin?
Binds to Antithrombin III. Which inactivates Thrombin (Factor 2)
How do you approach a bleeding patient (non life threatening)?
Is it primary or secondary hemostasis?
Primary: vag bleed, oral bleed, petechiae
Secondary: hematoma, hemarthroses
If a patient is bleeding with petechiae, oral bleed or vaginal bleed etc. (primary hemostasis) what lab do you want?
Platelet count
A bleeding patient with decreased platelets has thrombocytopenia. What are the three causes of thrombocytopenia?
- Production: BM, Aplastic anemia, Ca infiltrate, Cirrhosis
- Consumption: DIC, HIT, TTP, ITP
- Sequestration: spleen
A bleeding patient with vaginal bleeding oral bleed petechiae etc. and a normal platelet count has platelet dysfunction. Name five causes of platelet dysfunction
vWD NSAIDs ASA Clopidogrel Uremia (100s)
A “bleeding” pt comes in with hematoma or hemarthroses (secondary hemostasis). What lab study would you want first?
Mixing study
A bleeding patient comes in with hematoma hemarthroses and the mixing study corrects. What type of problem is there?
Factor deficiency: Vit K def Coumadin Cirrhosis DIC vWD
I’m bleeding patient comes in with hematoma and hemarthroses and the mixing study does not correct. What type of problem is there?
And inhibitor problem:
Hemophilia A/B
Sickle cell
Diagnose: A patient comes in with fever, autoimmune hemolytic anemia, thrombocytopenia, renal failure, Neuro symptoms
FATRN= TTP
What’s the difference between TTP and DIC?
TTP has decreased platelets and everything else normal in the DIC panel. DIC has everything abnormal in the DIC panel.
What’s the treatment for DIC?
Treat the underlying disease and give blood products including: platelets, cryo (fix dec fibrinogen), FFP (fix PT PTT INR), PRBCs (schistocytes)
How do you treat TTP
Exchange transfusion. never give blood products
Diagnosis: A patient comes in on heparin and starts to clot worse.
HIT
How do you treat HIT?
Lepirudin or Argatroban. Bridge to Coumadin
Diagnosis: A patient comes in asymptomatic and has extremely low platelets in the single digits
ITP
How do you diagnose and treat ITP?
This is a diagnosis of exclusion
Tx: platelets, corticosteroids, IVIG, RhoGAM, splenectomy, Rituximab
