Interactive Session on Clotting Profile

1. Interactive Session onClotting Profile Dr P T R Makuloluwa MBBS (Col), MD (Anaesthesiology), FRCA (Lond)

2. What are the steps in haemostasis ? • vascular response • formation of platelet plug • formation of fibrin clot

3. Formation of platelet plug • what tests can be done to assess the formation of platelet plug ? • platelet counts & bleeding time (BT) • what conditions are likely to interfere with this function ? • thrombocytopaenia, thrombasthenia • dengue fever ( platelet count) • what clinical features are seen in these patients with defective function of platelets ? purpuric rash, ecchymosis, bleeding gums

4. Fibrin clot formation • name the clotting pathways involved • intrinsic & extrinsic pathways • what clotting tests are available to assess the integrity of pathways ? • intrinsic pathway - APTT • extrinsic pathway - PT, INR • what pathway is defective in haemophiliacs • intrinsic pathway (due to deficiency of Factor V111)

5. how could deficiency of vitamin k interfere with clotting ? • vitamin k is necessary for the hepatic synthesis of Factors 11, V11, IX, X • deficiency of vitamin k, therefore interferes with the activity of both pathways

6. Fibrinolytic system • what tests can be used as indicators of of excessive fibrinolysis ? •  FDPs (fibrin degradation products) • D – dimers • what agents can be used for fibrinolysis ? • t - PA, streptokinase, urokinase • how does a patient with excessive fibrinolysis present ? • excessive bleeding

7. Practical on Clotting Profile Objectives: • Skills Student should be able to • perform the ward tests to measure BT & CT • interpret the results of clotting profile with reference to haemostatic derangements • analyze the results of clotting profile in the light of underlying clinical condition

8. Scenario 1 • A diagnosis of dengue fever was made in a child presented with bleeding gums & a purpuric rash on the skin • His bleeding time was 15 min. • what is the likely reason for prolonged BT low platelet counts • what other test could confirm the abnormality in haemostasis? platelet counts

9. Clinical Scenario 2 • 5 years old child presented with pain & swelling of right knee following a trivial injury • a similar episodes in the past with a diagnosis of haemophilia • comment on the haemostatic abnormality in this child • clotting defect due to deficiency of Factor VIII

10. comment on the likely results of clotting profile • platelet count: normal • bleeding time: normal • clotting time : prolonged • PT : normal • APTT: prolonged • what is the reason for prolonged APTT? • anabnormality in intrinsic clotting pathway

11. Clinical Scenario 3 • A heavy alcoholic having cirrhosis of liver presented with multiple bruises on the skin & bleeding from the nose (epistaxis) • what abnormalities are expected in the clotting profile & why? • prolonged PT • increased INR ratio due to defective extrinsic clotting pathway

12. prolonged APTT due to defective intrinsic pathway deficiency of all the clotting factors synthesized by liver

13. Scenario 4 • a patient with an artificial heart valve, on anticoagulant warfarin, awaiting major surgery • what are the most useful clotting tests to assess his state of coagulation & why? • PT • INR defective extrinsic pathway warfarin inhibit the synthesis of vitamin k dependent factors II, VII,IX,X

14. Scenario 5 • a patient on heparin, following an epidsode of deep vein thrombosis after surgery for fractured hip bone • what clotting test is useful in the assessment of haemostatic mechanisms & why ? • APTT heparin affects the activity of intrinsic pathway