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My Pathoma Unit 2 > Chapter 4 Hemostasis and related disorders > Flashcards

Chapter 4 Hemostasis and related disorders Flashcards

1
Q

What mediates transient vasoconstriction in step one of primary hemostasis?

A

Reflex neural stimulation and endothelin release.

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2
Q

What receptor do platelets use to bind vWF?

A

GIb?

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3
Q

Where does vWF release primarily come from?

A

WP bodies and alpha granules

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4
Q

After platelet adhesion, degranulation occurs, what does this produce?

A

ADP is released from dense granules and promotes exposure of GPIIb/IIIa receptors. TXA2 is made by COX and promotes platelet aggregation.

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5
Q

What coagulation factor is fibrinogen?

A

Ia

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6
Q

What are the major clinical features (broad) of disorders of primary hemostasis?

A

mucosal and skin bleeding

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7
Q

Are petechiae signs of a qualitative or quantitative platelet problem?

A

quantitative.

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8
Q

What is a normal platelet count?

A

150-400K per uL

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9
Q

What is a normal bleeding time?

A

2-7 min

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10
Q

What type of antibody mediates the destruction of platelets in Immune Throbocytopenic Purpura? where are they produced?

A

IgG made by splennic plasma cells

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11
Q

How are platelets consumed in ITP?

A

by splenic macrophages

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12
Q

name the demographic ITP acute and chronic form mainly affects?

A

Acute is seen in children several weeks after a viral illness and is self limiting. Chronic is seem in adults, usually women of childbearing age (may be primary or secondary, note that IgG can cross placenta).

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13
Q

What are the following laboratory studies likely to show in ITP; platelet count, PT/PTT, megakaryocytes on marrow biopsy?

A

decreased platelets, normal PT/PTT, Increases megakaryocytes

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14
Q

What is the initial treatment for ITP? what are two other alternativer?

A

Initial is corticosteroids (Children respond well, adults often relapse). Additional is IVIG but it is short lived, and splenectomy which removes source of antibodies as well as destruction.

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15
Q

What is the cause of Thrombotic thrombocytopenic Anemia? What is a common demographic? What is the deficiency due to?

A

Decreased levels of ADAMTS13 which is an enzyme that cleaves vWF multimers. Commonly in adult females the deficiency is due to an autoantibody, you can also have inherited deficiencies.

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16
Q

What is the cause of microangiopathetic hemolytic anemia in HUS? (general defect and what agents cause it) who does it commonly affect

A

HUS is due to endothelial damage by drugs or infection. Commonly E. cole O157:H7 dysentery in children (undercooked beef). E.Coli verotoxin damages endothelial cells and also has been shown to decrease ADAMTS13.

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17
Q

What are the clinical findings in TTP and HUS?

A

Skin and mucosal bleeding, microangiopathetic hemolytic anemia, fever, Renal insufficiency (more common in HUS), CNS abnormalities (More common in TTP)

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18
Q

What is Bernard-Soulier syndrome? What does the blood smear show?

A

genetic GIb deficiency; platelet adhesion is impaired. mild thrombocytopenia (due to decreased life span) and enlarged platelets to compensatory increased marrow function.

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19
Q

What is Glanzmann thrombasthenia?

A

Genetic GPIIb/IIIa degiciency; impaired aggregation of platelets.

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20
Q

How does aspirin interfere with primary hemostasis?

A

irreversibly inhibits COX thus decreasing TXA2 and platelet aggregation.

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21
Q

How does uremia affect primary hemostasis?

A

build up of nitrogenous waste product disrupts both adhesion and aggregation.

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22
Q

What coagulation factor is thrombin?

A

Factor II

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23
Q

What coagulation factors does the liver produce?

A

I, II, V, VII, IX, X, XI, protein C, S and antithrombin.

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24
Q

Where is factor VIII produced?

A

multiple tissues

25
Q

What are three general factors that help activate the coagulation cascade?

A

Exposure to an activating substance
Phospholipid surface of platelets
Calcium (released by dense granules)

26
Q

What are the activating factors for factor VII and XII?

A

VII -> tissure Thromboplastin (tissue factor)

XII -> subendothelial collagen.

27
Q

What is the inheritance pattern of Hemophilia A?

A

X-linked recessive (predominately affects males)

28
Q

What are the lab findings in hemophilia VIII

A

increase PTT normal PT decreased factor VIII and NORMAL platelet count.

29
Q

What is another name for hemophilia B?

A

Chistmas disease

30
Q

What is the most common acquired antibody against a coagulation factor? what test is used to distinguish these from primary deficiencies?

A

FVIII, mixing test.

31
Q

What is the most common inheritance pattern of Von Willibrand disease? Does it lead to a decrease in quantity or quality?

A

AD leading to decreased quantity (There are variations with decreased quality)

32
Q

What symptoms are seen in vWF?

A

mild mucosal and skin bleeding (deep tissue bleeding, joint and surgical bleeding are usually not seen)

33
Q

What laboratory findings are seen in Von Willebrands disease?

A

increased bleeding time, increase PTT (stabilizes factor VIII), abnormal ristocetin test

34
Q

What is the test used to detect von willebrands disease? How does it work?

A

ristocetin test, induces platelet aggluntination by causing vWF to bind GIb

35
Q

What is the standard treatment for Von Willebrands?

A

Desmopressin (ADH analog) which increases vWF release fro WP bodies.

36
Q

What enzyme activates vitamin K? where?

A

epoxide reductase in the liver (Coumadin blocks this)

37
Q

What factors are Vit K dependant?

A

II, VII, IX, X and protein C and S

38
Q

What 3 major scenarios does vit k deficiency occur in?

A

Newborns (lack of gut bacteria)
Prolonged antibiotics (killed gut bacteria)
Malabsorption

39
Q

What test is used to follow liver failure?

A

PT

40
Q

What happens in heparin induced thrombocytopenia? What is a fear complication? how is this managed?

A

heparin can form a complex with platelet factor 4 which can be immunogenic and lead to destruction via IgG. A feared complication is that fragments of destroyed platelets may activate remaining platelets, leading to thrombosis. What they do is stop the heparin and give another anticoagulant. (but not coumadin because these patients are at increased risk for coumadin necrosis)

41
Q

Name five primary issues that lead to secondary DIC

A

OB complications (Tissue factor in amniotic fluid)
Sepsis - endotoxins and cytokines (TNF alpha and IL1) induce endothelial cells to make tissue factor
Adenocarcinoma - mucin activates coagulation
APL - primary granules activate coagulation
Rattlesnake Bite - venom activates coagulation

42
Q

What do the laboratory findings for DIC include?

A

decreased platelets, increase PT/PTT, decreased fibrinogen, microangiopathic hemolytic anemia, elevated fibrin split products (particularly D-Dimer)

43
Q

What converts plasminogen to Plasmin

A

tPA

44
Q

What functions does plasmin have?

A

Cleaves fibrin and serum fibrinogen, destroys coagulation factors, and blocks platelet aggregation.

45
Q

What inactivates plasmin?

A

alpha 2 antiplasmin

46
Q

What are some examples of situations that may cause plasmin overactivity?

A

Radical prostectomy release of urokinase which activates plasmin.
Cirrhosis of liver results in underproduction of alpha2 antiplasmin.

47
Q

How does a disorder of fibrinolysis present?

A

With increased bleeding, similar symptoms to DIC.

48
Q

What laboratory findings are seen in a disorder of excessive fibrinolysis.

A

increase PT/PTT due to destroyed coagulation factors
increased bleeding time with normal platelet count
increased fibrinogen split products without D-Dimers.

49
Q

What is the treatment for excessive plasmin activity?

A

aminocaproic acid, which blocks the activation of plasmin.

50
Q

What features distinguish a thrombus from a postmortem clot?

A

Lines of Zahn (alternating layers of platelets/fibrin and RBCs)
Attachment to vessel wall.

51
Q

What are the 3 major risk factors for thrombosis?

A

Disruption in blood flow, endothelial cell damage, hypercoaguable state.

52
Q

Name 5 ways in which endothelial cells help prevent thrombosis.

A

1 Block exposure to SEC and underlying TF
2 Produce Prostacyclin (PGI2) and NO which are vasodilators and inhibitors of platelet aggregation
3 Secrete heparin like molecules.
4 secrete tPA
5 secrete thrombomodulin which redirects thrombin to activate protein C which inactivates factors V and VIII

53
Q

What does antithrombinIII do?

A

inactivates thrombin and coagulation factors.

54
Q

Name three causes of increased homocysteine levels?

A

Vitamin B12 deficiency, Folate Deficiency, Cystathione beta synthase deficiency.

55
Q

What are some symptoms of elevated homocysteine?

A

vessel thrombosis, mental retardation, lens dislocation, and long slender fingers.

56
Q

What do protein C and S do?

A

Inactivate 5 and 8

57
Q

What is factor V leiden?

A

Mutated V that doesnt have cleavages site for protein C or S

58
Q

What is prothrombin 20210A?

A

point mutation in prothrombin that results in upregulation

59
Q

How doe oral contraceptives increase the risk for thrombosis?

A

Estrogen induces increased production of coagulation factors.

My Pathoma Unit 2 (6 decks)

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