L20

Question 1

Blood clotting process

Answer 1

1. Vascular injury
   - vasoconstriction
   - trigger platelets and clotting factor response
   - platelets fill the loss of endothelial gaps
2. Adhesion
   - the loss of endothelial cells exposes glycoproteins
   - more platelets adhere
3. Activity of the clotting cascade
   - platelets then bind adhesive proteins (fibrinogen, vWF)
   - activate other platelets, clotting factors
4. Formation of a blood clot
   - formation of a visible fibrin clot on the platelet plug

Question 2

Factors preventing blood clotting

Answer 2

1. Physical factor:
   - continuous circulation of blood
   - smooth endothelium lining of the blood
2. Chemical factor:
   - presence of anticoagulant
   - inactivation of clotting factors
   - fibrinolysis by activation of plasminogen

Question 3

Life cycle of platelet

Answer 3

1. Megakaryocyte in bone marrow release pro-platelets
2. Pro-platelets mature in bloodstream
3. Platelet circulate in circulation for 7-10 days and apoptosis (die)
4. Decreased platelet levels stimulate increase in plasma thrompoietin
5. More megakaryocyte produced by bone marrow

Question 4

Thrombocytopenia

Answer 4

1. Normal or slightly increased PT and APTT
2. Outcome:
   - Prolonged clotting or spontaneous hemorrhage
   - idiopathic thrombocytopenia purpura
   - thrombotic thrombocytopenia purpura:
   small blood clots form in small blood vessels throughout the blood, used up platelets
3. Treatment: Fresh Frozen Plasma or plasma exchange

Question 5

Clinical manifestations of thrombocytopenia

Answer 5

1. Sudden onset of petechiae (tiny spots of bleeding under skin or in the mucous membrane) and ecchymoses (discoloration of skin due to bleeding underneath, e.g. bruising)
2. Bleeding into mucous membranes
   e.g. nosebleeds, gingival (gum) bleeding, GI, urinary, vaginal
3. Menorrhagia (prolonged and heavy menstrual flow) and metrorrhagia (irregular menstrual flow)
4. Prolonged bleeding after routine procedure

Question 6

Diagnostic test for idiopathic / immune thrombocytopenic purpura

Answer 6

• Decreased platelet count to less than 150 x 10^9 /L
• RBCs found in urinalysis

Question 7

Treatment of thrombocypenia

Answer 7

1. Corticosteroid: prevent depress antibody formation; reduce capillary leakage
2. Immunoglobulin
3. Immunosuppressants
4. Splenectomy: for patient intolerant to corticosteroids and have severe thrombocytopenia
5. Thrombopoietin receptor agonists: increase platelet production

Question 8

Nursing management of