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

Question 1

vascular and extravascular disorders are

Answer 1

disorders of blood vessels or the tissues surrounding the vessels

Question 2

vascular and extravascular disorders are due to

Answer 2

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

Question 3

Specific lab finding of vascular and extravascular disorders

Answer 3

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

Question 4

acquired vascular disorders include (3)

Answer 4

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

Question 5

Inherited disorders include (6)

Answer 5

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

Question 6

platelet disorders can be

Answer 6

quantitative (numbers)
or qualitative (function)

Question 7

Thrombocytopenia

Answer 7

decreased platelet count

Critical

Question 8

Thrombocytosis

Answer 8

increased platelet count

Question 9

Thrombocythemia

Answer 9

extreme increased platelet count

>1000 x10^9/L

Question 10

Lab finding in thrombocytopenia

Answer 10

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

Question 11

Causes of thrombocytopenia (3)

Answer 11

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

Question 12

Decreased or ineffective production of platelets

Answer 12

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

Question 13

Increased destruction or utilization of platelets causes

Answer 13

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

Question 14

Abnormal distribution of platelets causes

Answer 14

increased splenic pooling

spleenomegaly

Question 15

Functional disorders include (inherited and acquired) 3

Answer 15

Thrombopathies
Thrombasthenia
Bernard-Soulier Syndrome

Question 16

Thrombopathies and 2 types

Answer 16

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

Question 17

Thrombasthenia

Answer 17

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

Question 18

Bernard-Soulier

Answer 18

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

Question 19

Glanzmann’s Thrombasthenia lab results

Answer 19

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

Question 20

Bernard-Soulier Syndrome lab results

Answer 20

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

Question 21

Most common acquired platelet defect is due to

Answer 21

aspirin

Question 22

Enzyme inhibited by aspirin

Answer 22

cyclooxygenase