Module 4: Disorders of Hemostasis (from review- PLT disorders) Flashcards Preview

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Flashcards in Module 4: Disorders of Hemostasis (from review- PLT disorders) Deck (22):
1

vascular and extravascular disorders are

disorders of blood vessels or the tissues surrounding the vessels

2

vascular and extravascular disorders are due to

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

3

Specific lab finding of vascular and extravascular disorders

Bleeding time/closure time - prolonged
Capillary fragility- positive
Plt cunt- normal
PT/PTT- normal

4

acquired vascular disorders include (3)

1) Senile purpura: bruising in the aged, atrophy and degeneration of connective tissue
2) Simple easy bruising
3) Secondary vascular purpuras: immune damage, Vit C deficiency, Henoch-Schoenlein Syndrome

5

Inherited disorders include (6)

1) Hereditary Hemorrhagic Telangiectasia: dilations of capillaries
2) Ehler-Danlos Syndrome: Loss of elasticity in the epidermis and sup epidermal tissues (deformable skin)
3) Marfans Syndrome: Abnormal fibrillar in connective tissue
4) Osteogenesis Imperfecta: defective collagen formation, brittle bones
5) Homocystinuria: amino acid disorder
6) Pseudo Xanthoma Elasticum: disorder of elastin in which elastic tissue mineralize

6

platelet disorders can be

quantitative (numbers)
or qualitative (function)

7

Thrombocytopenia

decreased platelet count

Critical

8

Thrombocytosis

increased platelet count

9

Thrombocythemia

extreme increased platelet count
>1000 x10^9/L

10

Lab finding in thrombocytopenia

decreased plt count
prolonged bleeding time
prolonged closure time
poor clot retraction

11

Causes of thrombocytopenia (3)

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

12

Decreased or ineffective production of platelets

marrow hypoplasia: all cells decreased, decreased megakaryocytic in the Bone marrow

Ineffective megakaryopoiesis: megakaryocytic fail to survive or to normally release platelets, normal looking bone marrow

13

Increased destruction or utilization of platelets causes

Excessive consumption of platelets: Thrombotic thrombocytopenic purpura (TTP): ADAMTS 13 deficiency, DIC, Hemolytic ureic syndrome (HUS)

Platelet antibodies: Immune thrombocytopenic purpura (an abnormal antibody with specificity for 1 or more platelet membrane glycoproteins)

Transfusions

14

Abnormal distribution of platelets causes

increased splenic pooling

spleenomegaly

15

Functional disorders include (inherited and acquired) 3

Thrombopathies
Thrombasthenia
Bernard-Soulier Syndrome

16

Thrombopathies and 2 types

Are inherited defects of the platelet release reaction:
Storage pool disease: deficiency of alpha and/or dense granules, platelets cannot aggregate

Primary secretion Defects: causes of release defects due to deficiencies of enzymes and other secondary messengers that transmit signals to cause the release

17

Thrombasthenia

Glanzmann disease, failure of primary aggregation, reduced amounts of GPIIb/IIIa

18

Bernard-Soulier

giant platelet syndrome, failure of platelet adhesion, reduced amounts of GPIb

19

Glanzmann's Thrombasthenia lab results

Platelet count: Normal
Platelet morphology: Normal
Closure/bleeding time: Prolonged
Platelet aggregation with Ristocetin: Normal
Platelet glycoprotein defect: GPIIb/IIIa

20

Bernard-Soulier Syndrome lab results

Platelet count: Normal/decreased
Platelet morphology: Giant
Closure/bleeding time: Prolonged
Platelet aggregation with Ristocetin: Abnormal
Platelet glycoprotein defect: GPIb/IX

21

Most common acquired platelet defect is due to

aspirin

22

Enzyme inhibited by aspirin

cyclooxygenase