Hemostasis

Question 1

coagulopathy

Answer 1

A condition characterized by impaired clotting of blood

Question 2

Hypercoaguability (thrombophilia)

Answer 2

A condition characterized by an increased tendency toward blood clotting

Question 3

Reflex vasoconstriction

Answer 3

1st step of primary hemostasis

Question 4

2nd step of primary hemostasis

Answer 4

vWF line surface of disruption at subendothelial collagen, platelets bind to vWF

Question 5

3rd step of primary hemostasis

Answer 5

Platelets activate and degranulate

Binding to vWF causes change in platelet shape -> dump mediators from granulation. Mediators are ADP and TXA2.

Question 6

Platelet aggregation

Answer 6

4th step in primary hemostasis

Question 7

Primary hemostasis

Answer 7

Form a weak platelet plug. Mediated by platelet wall interactions

Question 8

Secondary hemostasis

Answer 8

Stabilizes platelet plug by forming a fibrin meshwork. Mediated by coagulation cascade.

Question 9

Tertiary hemostasis

Answer 9

clot limitation and fibrinolysis - need to limit clot size and contain the reaction

Question 10

Plasmin

Answer 10

In fibrinolysis, this molecule removes the thrombus by cleaving fibrin and fibrinogen, destroys coagulation factors and blocks platelet aggregation

Question 11

tPA

Answer 11

converts plasminogen to plasmin to start fibrinolysis

Question 12

Normal endothelium

Answer 12

Expresses proteins that inhibits platelet aggregation, act as vasodilators, facilitate the inactivation of thrombin

Question 13

vWF

Answer 13

Line surface of endothelial disruption at subendothelial collagen. Attach to platelets

Question 14

Bone marrow by megakaryocytes

Answer 14

Where are platelets made?

Question 15

Factor VIII

Answer 15

vWF protects which factor

Question 16

Liver

Answer 16

Coagulation cascade proteins are made here except VIII

Question 17

VIII

Answer 17

Only factor made in endothelial cells

Question 18

II, VII, IX, X

Answer 18

Vitamin K dependent factors

Question 19

V, VIII, XI, XIII, platelets and fibrinogen

Answer 19

Thrombin activates

Question 20

XIII

Answer 20

Enzyme that crosslinks fibrin and helps to stabilize clot, activated by thrombin

Question 21

X

Answer 21

Active form of this factor activates thrombin, intrinsic and extrinsic pathways feed together to this factor

Question 22

V and VIII

Answer 22

Thrombin can be an inhibitor to stop clotting cascade. Bind thrombomodulin, protein C, protein S which inactivate these factors

Question 23

Antithrombin

Answer 23

Inhibits all the serine proteases (Xa, XIa, IXa, XIIa, VIIa) but especially thrombin

Question 24

Heparin

Answer 24

Binds to antithrombin and makes it a much more potent inhibitor of thrombin
Works mostly on thrombin, but also XI and X. Major effect is intrinsic so PTT effects more striking

Question 25

TFPI

Answer 25

Inhibits Xa and VIIa

Question 26

PT

Answer 26

When extrinsic pathway is affected, this time is abnormal

Question 27

PTT

Answer 27

When intrinsic pathway is affect, this time is abnormal

Question 28

Abnormal PT

Answer 28

Defect in factor VII shows

Question 29

Abnormal PTT

Answer 29

Defect in factor XII, XI, IX, or VIII shows

Question 30

Abnormal PT and PTT

Answer 30

Defect in factor II, V, X, or fibrinogen shows

Question 31

TEG (thromboelastography)

Answer 31

Mechanical test of clotting strength development. Assesses ability of platelets to pull the fibrin clot into a tight mesh and of desolution

Question 32

Defects in primary hemostasis

Answer 32

Platelet problems, Von Willebrand disease

Question 33

Defects in secondary hemostasis

Answer 33

Hemophilia, vitamin K deficiecny, anticoagulation

Question 34

von Willebrand's disease

Answer 34

Most common inherited bleeding disorder. Autosomal DOMINANT. Causes "mucosal" bleeding (nosebleeds, prolonged bleeding with dental work, heavy menses, easy bruising, etc) Usually type 1 is mild, but potentially a problem with major injury or surgery Unlike most platelet problems, it is inherited, life-long, a/w family history

Question 35

von willebrand testing

Answer 35

Measure antigen level, activity (ristocetin cofactor activity), factor VIII level, multimer assay

Question 36

Petechiae, bruising, mucosal bleeding

Answer 36

Clinical presentation of platelet problems (primary hemostasis)

Question 37

ITP

Answer 37

Immune reaction to platelets. Very low platelet counts, but normal bleeding time. Platelets produced are young and super functioning

Question 38

VIII, IX

Answer 38

X-linked recessive defects in these factors (hemophilia)

Question 39

XII

Answer 39

If defect in this factor, thrombin will still activate the next step (XI)

Question 40

Hemophilia A

Answer 40

X-linked recessive, factor 8 deficiency | Bleeding deep and delayed

Question 41

Hemophilia B

Answer 41

X-linked recessive, factor 9 deficiency | Bleeding deep and delayed

Question 42

Acquired factor VIII inhibitor

Answer 42

Acquried hemophilia, antibody against this factor. Occurs most commonly in elderly patients, also seen postpartum, in rheumatologic disease, and malignancy. Presents most commonly with soft tissue bleeding Prolonged PTT

Question 43

Vitamin K deficiency

Answer 43

See a prolonged PT and PTT, but more commonly you will see only a prolonged PT From a dietary deficiency (rare), antibiotics, malabsorption, newborn, and coumarins To treat, give supplements (carefully if back on Warfarin), plasma (short term fix to get factors), and Kcentra (for emergencies)

Question 44

Warfarin

Answer 44

Followed using the PT. Blocks recycling of vitamin K and causes deficiency

Question 45

Causes of a prolonged PT

Answer 45

Warfarin use, liver disease, Vit K deficiency, Factor VII deficiency

Question 46

Causes of a prolonged PTT

Answer 46

Heparin use, factor deficiency (VIII, IX, XI, XII, von willebrand (protects 8)), antiphospholipid antibody (lupus inhibitor), DIC

Question 47

Lupus anticoagulant phenomenon

Answer 47

Prolonged phospholipid-dependent coagulation tests caused by autoantibodies against phospholipid-binding proteins- cause hypercoagulable state. Anti-phospholipid syndrome is associated with thrombosis, not bleeding (more prone to thrombosis) In vitro phenomenon - test makes it look like a bleeding problem with prolonged PTT In vivo they are not anticoagulants but promote thrombosis

Question 48

DIC

Answer 48

Coagulation system is activated everywhere. From sepsis, viral hemorrhagic fevers, trauma, cancers, OB complications, toxins (rattlesnakes), vascular disorders, immunologic disorders,etc Usually a SECONDARY disease Intravascular deposition of fibrin leads to trombosis of small vessels (microangiopathic hemolysis), depletion of platelets and coag factors leads to bleeding

Question 49

Schistocytes or helmet cells

Answer 49

Types of cells seen in DIC and TTP from microangiopathic hemolysis

Question 50

Lab findings for DIC

Answer 50

Prolonged PT, PTT Decreased platelet count and fibrinogen Increased D- dimers***** seen here because fibrin is being cut Abnormalities on peripheral smear (like schistocytes)

Question 51

Anti-thrombin III deficiency

Answer 51

Most common severe inherited thrombophilic disorder. Can cause venous thrombosis and embolism

Question 52

Antithrombin, Protein C, Protein S deficiencies

Answer 52

Uncommon causes of inherited thrombophilia associated with high thrombotic risk

Question 53

Factor V Leiden

Answer 53

Common cause of inherited thrombophilia associated with lower thrombotic risk- mutation that keeps factor activated longer than it should be

Question 54

Liver disease

Answer 54

Have a hard time forming clots because of loss of all factors but 8, can't activate Vit K ALSO have a hard time inhibiting clots so have prolonged PT and PTTs but may actually be prone to thrombosis