Hematological III

Question 1

What is hemotasis

Answer 1

is a sequence/chain reaction of events leading to the cessation of bleeding bt formation of stable fibrin platelet plug

Question 2

Formation of hemostasis (4)

Answer 2

1. Vascular constriction
2. formation of platelet plug (within mins)
3. Formation of blood clot (occurs within mins to hours
4. Tissue repair (occurs within days-weeks of initial impact)

Question 3

What happens in step 1: vascular contraction/vascular wall injury

Answer 3

• Vessel contracts as result of initial injury
• Vasoconstriction causes blood flow turbulence and stasis
• this then causes release of thrombogenic factors release (thromboplastin, vWF)
• coagulation initiation

Question 4

What happens in step 2: platelet phase of hemostasis (3 subphrases)

Answer 4

Endothelial cells begin platelet phase of clot formation

1. Adhesion- vWF binds to CD42 receptor on surface of damaged enothelium (leading to adhesion of thrombocytes), adhesion causes platelets to degranulate
2. activation- the release of alpha granules and dense bodies causes activation of the GP-3A receptor nd initiates binding of fibrinogen
3. Aggregation- formation of platelet chain begins

Question 5

What constitutes thrombocytopenia and thrombocytosis

Answer 5

Throbocytopenia- platelet count below 150 000

Thrombocytosis- platelet count above 400 000

Question 6

what happens in step 3: formation of Blood clot

Answer 6

1. activation of prothrombin (makes thrombin)
2. Thrombin then acts on soluble form of fibrinogen into insoluble fibrin
3. Fibrin allows proper formulation of blood clot which activates fibrinolytic system
4. fibrinolytic system works to dissolve and reorganize clot

Question 7

What is the intrinsic vs extrinsic clotting pathway

Answer 7

Instrincic pathway- surface contract (abnormalities within endothelial vessel lining occur as a result of turbulent flow)

Extrinsic pathway- Actual damage occurs- Physical damage over a vessel causing release of thrombus

Question 8

What is the fibrinolytic system

Answer 8

Both the intrincic and extrincic path lead to common pathway which eventually leads to the formation of fibrin

Fibrin clot activates fibrinogen system which acctivates plasminogen and then plasmin which reorganizes clot

Question 9

What are the different types of bleeding disorders (4)

Answer 9

1. Due to vascular wall abnormalities
2. Thrombocytopenias
3. Thrombasthenias (defective platelets)
4. Abnormalities in clotting factors (hemophilia etc)

Question 10

Ex of vascular wall abnormalities

Answer 10

• Ehlers danlos
• Marfan syndrme
• Scurvy
• infextious and hypersensitive vasculidies

Question 11

What is idiopathic thromocytoopenic purpura

Answer 11

type 2 hypersensitivity reaction against GPIIb-IIIa and GPIb-IX platelet antigens

Question 12

what is thrombotic thrombocytopenia purport a def in

Answer 12

Def in ADAMTS13 enzyme

Causes clinical presentation of thrombocytopenia

Question 13

What is heparin induced thrombocytopenia and pathogenesis

Answer 13

thrombocytopenia due to unfractionated heparin tx

-IgG antibodies bind PF4-herapin complex and cause platelets activation and thrombosis

Question 14

What is the mc thrombotic condition

Answer 14

Hemolytic uremic syndrome (hamburger disease)

Question 15

What is hemolytic ureic syndrome due to

Answer 15

Mc initial stage is gastro-enteritis w bloody diarrhea caused by E.Coli

Question 16

What is Virchow Triad (3)

Answer 16

triad of factors involved in thrombosis

1. Hypercoaguality
2. Hemodynalic alterations
3. Endothelial or vessel wall injury

Question 17

What is antiphospholipid antibody syndrome and clinical features

Answer 17

Antibodies against several negatively charged phospholipids (autoimmune disorder)

clinical fx- arterial and venous thrombosis, spontaneous abortion, immune mediated thrombocytopenia

Question 18

What is hemophilia A and what is it due to

Answer 18

X linked recessive condition
Due to def in Factor VIII

(affects mosltly males)

Question 19

What is the signs and symptoms of hemophilia A

Answer 19

Severe prolonged bleeding during surgical procedures
spontaneous hemorrhages in mm + jts
Easy bruising and hematomas

Question 20

What is Hemophilia B and what is it due to

Answer 20

X linked

Deficiency in Factor IX

Question 21

What is disseminated intravascular coagulation due to

Answer 21

Always due to or secondary to preceding disorder

Hemmorage, thromboembolism, sepsis, AML, Adenocarcinoma

Question 22

Pathogenesis of DIC

Answer 22

Massive tissue destruction, sepsis and endothelial injury activate and release endothelial derived thromboplastin

leads to widespread microvascular thrombosis

Question 23

Clinical presentation of DIC

Answer 23

multiorgan failure
adrenal cortex hemmorages
Manifests quick

Question 24

What causes a hemolytic transfusion reaction

Answer 24

Primary exposure to RBC carrying antigen

secondary exposure to RBC carrying the antigen

Question 25

What is a non hemolytic transfusion reaction

Answer 25

HLA or major histocompatibility complex system

Prior exposure to hLA by transfusion or preg `

Question 26

What is circulatory overload

Answer 26

May result from transfusion of excessive volume hemorrage

Question 27

What is transfusion related acute lung injury

Answer 27

Non cardiac pulmonary edema within 6 hrs of tranfusion

Question 28

What is transfusion associated graft versus host disease

Answer 28

Transfusion of competent lymphocytes into an immune incompetent recipient
Transfused cells engraft over around 10 days and then moont immune attack on the donor due to histoincompatibiliy