3a bleeding disorders Year 4 Internal Medicine Notes

3a bleeding disorders Year 4 · Internal Medicine Collection: 4TH YEAR ALL NOTES / IMED / IMED 4.2 / Mogere -- Slide 1 BLEEDING DISORDERS Dr Alex Mogere Consultant Physician Slide 2 HEMOSTASIS 1. VASCULAR PHASE 2. PLATELET PHASE 3. COAGULATION PHASE 4. FIBRINOLYTIC PHASE Slide 3 Hemostasis Lab Tests CBC-Plt BT,(CT) PT PTT Plt Study Morphology Function Antibody Slide 4 NORMAL CLOTTING Response to vessel injury 1. Vasoconstriction to reduce blood flow 2. Platelet plug formation (von willebrand factor binds damaged vessel and platelets)\n3. Activation of clotting cascade with generation of fibrin clot formation 4. Fibrinolysis (clot breakdown) Slide 5 Normally the ingredients, called factors, act like a row of dominoes toppling against each other to create a chain reaction.\nIf one of the factors is missing this chain reaction cannot proceed. CLOTTING CASCADE Slide 6 VASCULAR PHASE WHEN A BLOOD VESSEL IS DAMAGED, VASOCONSTRICTION RESULTS. THIS IS CAUSED BY TXA2 FROM ACTIVATED PLTS, AND INJURED EPITHELIAL CELLS, NERVOUS SYSTEM REFLEXES FROM PAIN, DIRECT INJURY TO VASCULAR SMOOTH MUSCLE Slide 7 PLATELET PHASE PLATELETS ADHERE TO THE DAMAGED SURFACE AND FORM A TEMPORARY PLUG. Slide 8 COAGULATION PHASE THROUGH TWO SEPARATE PATHWAYS THE CONVERSION OF FIBRINOGEN TO FIBRIN IS COMPLETE. Slide 9 THE CLOTTING MECHANISM INTRINSIC EXTRINSIC PROTHROMBIN THROMBIN FIBRINOGEN FIBRIN (II) (III) (I) V X Tissue Thromboplastin Collagen VII XII XI IX VIII Slide 10 FIBRINOLYTIC PHASE ANTICLOTTING MECHANISMS ARE ACTIVATED TO ALLOW CLOT DISINTEGRATION AND REPAIR OF THE DAMAGED VESSEL. Slide 11 HEMOSTASIS DEPENDENT UPON: -Vessel Wall Integrity -Adequate Numbers of Platelets -Proper Functioning Platelets -Adequate Levels of Clotting Factors -Proper Function of Fibrinolytic Pathway Slide 12 LABORATORY EVALUATION -BLEEDING TIME (BT) -PROTHROMBIN TIME (PT) -PARTIAL THROMBOPLASTIN TIME (PTT) -PLATELET COUNT -THROMBIN TIME (TT) Slide 13 PLATELET COUNT NORMAL 100,000 - 400,000 CELLS/MM3 \n< 100,000 Thrombocytopenia \n50,000 - 100,000 Mild Thrombocytopenia \n< 50,000 Severe Thrombocytopenia Slide 14 BLEEDING TIME PROVIDES ASSESSMENT OF PLATELET COUNT AND FUNCTION Evaluates how well a pt’s blood is clotting. Evaluates how long it takes the vessels damaged to constrict, And how long it takes for platelets in the blood to seal off the hole.\n\nNORMAL VALUE\n2-8 MINUTES Slide 15 PROTHROMBIN TIME -Measures Effectiveness of the Extrinsic Pathway. -measures how long blood takes to clot -can be used to check bleeding issues -also used to check whether anticoagulant is working What does it mean when its high?\n\nNORMAL VALUE\n10-15 SECS Slide 16 PARTIAL THROMBOPLASTIN TIME(PTT)/aPTT -Measures Effectiveness of the Intrinsic\nPathway -the coagulation factors measured: 1,2,5,7,10,11,12 Also used to monitor the Tx effect of heparin NORMAL VALUE\n25-40 SECS Slide 17 THROMBIN TIME Time for Thrombin To Convert Fibrinogen to Fibrin -measures the time it takes for a clot to form in the plasma of a blood sample containing an anticoagulant after an excess of thrombin has been added -used to assess blood coagulation disorders -the test is repeated with pooled plasma from normal pts A Measure of Fibrinolytic Pathway NORMAL VALUE\n9-13 SECS Slide 18 So What Causes Bleeding Disorders? -VESSEL DEFECTS -PLATELET DISORDERS -FACTOR DEFICIENCIES -OTHER DISORDERS ? ? Slide 19 VESSEL DEFECTS Vitamin c deficiency Bacterial & viral infections \nAcquired & Hereditary conditions Slide 20 Vascular defect - cont. Infectious and hypersensitivity Vasculitides\n- Rickettsial and meningococcal infections\n- Henoch-Schonlein purpura (immune) Slide 21 PLATELET DISORDERS Thrombocytopenia Thrombocytopathy Slide 22 THROMBOCYTOPENIA Inadequate number\nof platelets Slide 23 THROMBOCYTOPATHY adequate number but abnormal function Slide 24 THROMBOCYTOPENIA -drug induced\n-bone marrow failure -hypersplenism -other causes Slide 25 -OTHER CAUSES Lymphoma HIV Virus Idiopathic Thrombocytopenic Purpura (ITP) Slide 26 THROMBOCYTOPATHY UREMIA INHERITED DISORDERS-eg VWB dse,thrombasthenia, Bernard-Soulier syndrome MYELOPROLIFERATIVE DISORDERS DRUG INDUCED Slide 27 FACTOR DEFICIENCIES (CONGENITAL) -HEMOPHILIA A\n -HEMOPHILIA B -Von WILLEBRAND’S DISEASE Slide 28 FACTOR DEFICIENCIES -HEMOPHILIA A (Classic Hemophilia) 80-85% of all Hemophiliacs Deficiency of Factor VIII Lab Results - Prolonged PTT -HEMOPHILIA B (Christmas Disease) 10-15% of all Hemophiliacs Deficiency of Factor IX Lab Test - Prolonged PTT Slide 29 FACTOR DEFICIENCIES -VON WILLEBRAND’S DISEASE Deficiency of VWF & amount of Factor VIII Lab Results - Prolonged BT, PTT Slide 30 OTHER DISORDERS (ACQUIRED) ANTICOAGULANTS COUMARIN HEPARIN LIVER DISEASE MALABSORPTION BROAD-SPECTRUM ANTIBIOTICS Slide 31 INHIBITORS Upto 30% of people with severe haemophilia A develop an antibody to the clotting factor they are receiving for treatment. These antibodies are known as inhibitors. These patients are treated with high doses of FVIIa for bleeds or surgery.