Module 4: Disorders of Hemostasis Flashcards Preview

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Flashcards in Module 4: Disorders of Hemostasis Deck (101)
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1

Vascular and extravascular disorders are due to:

a defect in the structure or function of the vascular endothelium or sub endothelium (collagen)

2

In vascular and extravascular disorders, platelet count, PT and PTT would be:

normal

3

In vascular and extravascular disorders, bleeding time or closure time would be:

prolonged

4

Acquired vascular disorders include:

Senile purapura
Simple easy bruising
Secondary vascular purapuras

5

What is senile purapura?

Bruising in the aged, atrophy and degeneration of the connective tissue

6

Inherited vascular disorders include:

Hereditary hemorrhagic telangiectasia
Ehlers-Danlos syndrome
Marfans Syndrome
Osteogeneis imperfecta
Homocystienuria
Pseudo Xanthoma Elasticum

7

Thrombocytopenia means:

Decreased platelet count
Critical, less than 20 x 10^9/L

8

Thrombocytosis means:

Increased platelet count

9

Thrombocythemia means:

Extreme increased platelet count >1000 x 10^9/L

10

Lab findings in thrombocytopenia:

Decreased platelet count
Prolonged bleeding time
Prolonged closure time
Poor clot retraction

11

Thrombocytopenia is caused by:

Decreased or ineffective production of platelets
Increased destruction or utilization of platelets
Abnormal distribution

12

What happens in marrow hypoplasia?

All cells are decreased, decreased megakaryocytes in the bone marrow

13

What happens in ineffective megakaryopoiesis?

Megakaryocytes fail to survive or to normally release platelets (low platelet count)
Bone marrow appears normal

14

What is hereditary hemorrhagic telangiectasia?

Autosomal dominant defect in the subendothelial collagen
Results in dilation of capillaries, loss of vascular patency (petechiae), spontaneous bleeds from mucous membranes

15

What is Ehlers-Danlos Syndrome?

Inherited disorder
Loss of elasticity in the epidermis and sub epidermal tissues

16

What is Marfan Syndrome?

Defect in chromosome 15
Abnormal fibrillan in connective tissue and weakness

17

What is Osteogenesis Imperfecta?

Genetic disorder of defective collagen formation characterized by bones that break easily

18

What is homocystinuria?

Inherited disorder of the metabolism of the amino acid methionine

19

What Pseudo Xanthoma Elasticum?

Inherited disorder of elastin in which elastic tissues in the body (skin, vessels, retina) become mineralized, especially with calcium

20

Secondary vascular purapuras are:

endothelial damage from a variety of causes (immune damage, vitamin C deficiency, endotoxins, liver disease, etc)

21

Clinical findings in thrombocytopenia:

Skin purapura
Mucosal hemorrhages
Increased bleeding after trauma

22

Conditions causing excessive consumption of platelets

Thrombotic thrombocytopenic purapura (TTP)
Disseminated intravascular coagulation (DIC)
Hemolytic uremic syndrome (HUS)

23

What is thrombotic thrombocytopenic purapura (TTP)?

Disorder caused by a deficiency of the metalloprotease enzyme ADAMTS-13 (required to break up ultra-large vWF multimers to smaller, less adhesive multimers)

24

Lab findings in TTP

Increased megakaryocytes in the bone marrow
Increased megathrombocytes in the blood smear
Increased platelet aggregation in blood film
Decreased platelet survival (radioisotope method)

25

What is immune thrombocytopenic purapura (ITP)?

Platelet antibody (usually GPIIb/IIIa or GPIb) sensitizes the platelets causing premature removal by macrophages
Usually secondary to viral infections or drugs
May be acute (rare, in children, usually after vaccination or viral infection) or chronic

26

Lab findings in ITP

Increased megakaryocytes in the bone marrow
Platelet antibody in serum
Decreased platelet survival

27

Lab findings in thrombocytosis

Increased platelet count with abnormal morphology
Increased megathrombocytes
Increased red cell fallout in the clot retraction test
Normal or prolonged bleeding time

28

Abnormal platelet function is indicated by:

skin and mucosal hemorrhage with prolonged bleeding time and normal platelet count

29

Storage pool diseases (granule defects)

Secondary aggregation disorder
Deficiency of dense and/or alpha granules

30

Primary secretion defects (enzymatic pathway defects)

Deficiencies of enzymes and other secondary messengers that transmit signals from surface receptors to cause the release of the granule contents
Resemble storage pool deficiencies but no quantity or content abnormalities