hemostasis

Question 1

3 key components of normal hemostasis

Answer 1

vascular endothelium
platelets
clotting factors

Question 2

define normal hemostasis

Answer 2

physiologic process by which blood vessel lining cells, platelets, and coagulation factors in blood work together to stop bleeding

Question 3

define coagulation

Answer 3

process by which liquid blood converted to solid clot.

Question 4

3 requirements for optimal function of normal hemostasis

Answer 4

• normal blood tempp
• normal pH
• normal calcium concentration.

Question 5

process of primary hemostasis

Answer 5

1. exposed subendothelial cells. vWF sees and spreads like glue . vWF adheres and sticks to platelet via gp1b. = platellet adhesion
2. platelet secretion -platelet secretes contents to attract more platelets
3. platelet aggregation - via gp2b3a platelet binds fibrinogen to form blood clot

Question 6

lab eval of primary hemostasis

Answer 6

platelets: number, size morphology, special platelet function tests, medication history
vWF = factor level & fxn

Question 7

secondary hemostasis.

Answer 7

extrinsic 7–> 10 -> 5 -> 2 ->1
intrinsic 12 -> 11 -> 9_>(cofacotr 8) -> 10 -> 5 -> 2-> 1
after 1 - crosslinked qith 13.
activation of factor 2 AKA thrombin = key. converts fibrinogen to fibrin = stable clot formed.

factor 7 - extrinsic factor. quickly turns off pathway after beginning activation.
thrombin activates facotrs 11, 8, 5, in pathway. so factor 12 isnt really necessary for coagulation.

Question 8

lab eval of secondary hemostasis

Answer 8

PTT = assess intrinsic pathway - activate factor 12 in lab.
PT = measure extrinsic pathway
converted to INR - international normalization ratio.
detecting clot formation in vivo = optical density, electromechanical.

Question 9

define fibrinolysis

Answer 9

normal process that breaks down/lyses clot away in time.

plasminogen – activated to plasmin breaks down fibrin.

Question 10

lab evaluation

Answer 10

test fibrinogen, d-dimers, other special tests

Question 11

bleeding disorders

Answer 11

acquired or hereditray.
acquired more frequent.
categories? platelet, VWF, factor deficiencies
cause of acquired: meds, alcohol ,liver/kidney failure,

Question 12

hereditary - primary hemostasis defect
cause
clinical presentation

Answer 12

causes: VWF disease; platelet dysfunction

clincial presentation: muco-cutaneous bleeding: nose bleeds, heavy periods.

Question 13

secondary hemostasis defects
cause
clinical presentation

Answer 13

cause: low coagulation factors
x-linked - hemophilia A (deficient factor 8)
hemophilia B - deficient factor 9.
autosomal recessive - hemophilia C.
clinical presentation: deep tissue hematoma - bleeding in joints/muscles.

Question 14

vWF disease

Answer 14

low or abnormal
autosomal dominant.
most common hereditary disorder.
presents: muco-cutanesous. usually mild or asymptomatic

Question 15

hereditary platelet disorders

Answer 15

present w muco-cutaneous bleeding.
treatment = platelet transfusion.
- bernard-soulier: autosomal recessive, gp1b deficiency. no platelet adhesion. = severe bleeding

glanzmann’s thrombasthenia: autosomal recessive, gp2b3a deficiency. no platelet aggregation or binding to fibrinogen. = severe bleeding
platelet granule abnormalities/secretion defects = no granules to be secreted. cant recruit/activate other platelets to amplify platelet adhesion

Question 16

hereditary coagulation factors disorders

Answer 16

hem A (x): facotr 9
hem B (X): facotr 8
presentation of above: mild (excess bleed w trauma); moderate (excess bleed w minor injury); severe = spontaneous bleeding.
treat: replace deficient factor. 
hem C (auto): factor 6

Question 17

antiplatelet agents & anticoagulants

Answer 17

antiplatelet = inhibit platelet function
anticoag = inhibit coagulation.

Question 18

clinical and lab approach to hemostasis and coagulation

Answer 18

• screen? not rlly.
  clinical history is important. family history, bleeding history, meds, past medical, surgical history.
  physical exam
  lab evaluations = basline. if concerned about those - do VWF factor & function; platelet fxn, hematology consultation