CME: Bleeding disorders - Diagnostic Approach
- 1. DR.G BALAJI . PROF.DR.G. SUNDARAMURTHY’S UNIT
- 2. Disorders of blood coagulation : Inherited or acquired coagulation disorders. Disorder of vessels Disorders of platelets- quantity or function
- 3. Hemostasis BV Injury Platelet Aggregation Platelet Activation Blood Vessel Constriction Coagulation Cascade Stable Hemostatic Plug Fibrin formation Reduced Blood flow Damage/contact. Primary hemostatic plug Neural CBC- Plt BT ,(CT) PT PTT Platelet study Antibody tests Factor Assay Contact
- 4. Type of Bleeding ecchymoses petechiae epistaxis deep soft tissue bleed hemarthroses GI bleeding
- 5. Tests of Hemostasis: Screening tests : Bleeding.T - 10m. Platelet & BV function Prothrombin.T – Extrinsic, aPTT – Intrinsic Thrombin.T – common path. Specific tests : Factor assays – hemophilia. Tests of thrombosis – TT, FDP, Platelet function studies: Adhesion, Aggregation, Release tests. Bone Marrow study
- 6. Pre-analytic errors Problems with blue-top tube Partial fill tubes Vacuum leak and citrate evaporation Problems with phlebotomy Heparin contamination Wrong label Slow fill Underfill Vigorous shaking Biological effects Hct ≥55 or ≤15 Lipemia, hyperbilirubinemia, hemolysis Laboratory errors Delay in testing Prolonged incubation at 37°C Freeze/thaw deterioration
- 7. Bleeding time Measure of efficiency of vascular or platelet phases . Do not discriminate between vascular defects , thrombocytopenia or platelets dysfunction. Not reproducible. Not a screening test . normal bleeding time do not exclude a bleeding disorder - american society of clinical pathologists.
- 8. Platelets enumeration Direct or automated methods. Normal: 1.5 lakhs- 4.5 lakhs Falsely low platelets counts- PSEUDOTHROMBOCYTOPENIA platelets agglutinins, paraproteinemias, giant platelets, lipemia, EDTA induced platelets clumping. Flasely high platelets counts: Microspherocytes, WBC/RBC fragments, pappenheimer bodies.
- 9. Platelets function assays Platelets aggregation using platelets rich plasma.- standard method. Nephelometric or photometric measurements. ADP- produce platelets aggregation directly irrespective of release of ADP from platelets. RISTOCETIN - antibiotic that induce platelets aggregation in presence of von Willebrand factor. Collagen, epinephrin, thrombin- cause platelet aggregation by release reaction.
- 10. Platelet function analyser- PFA 100 hemoSTATUS SYSTEM- modified activated clotting time test. To monitor cardio pulmonary bye-pass system. Verify now system Hemostasis analysis system. DiaMed- Impact-R System
- 11. Coagulation tests All tests on citrated plasma except D- Dimer. Nine parts of blood to one part of citrate. 3.2% sodium citrate. Blue topped vacuum blood collection tubes.
- 12. Blood Coagulation & Tests
- 13. Activated partial thromboplastin time Intrinsic and common pathway . When mixture of plasma and phospholipid platelets substitute is re calcified, fibrin is formed in the presence of factors in intrinsic pathway and common pathway. Platelet substitute -chloroform extract of brain, Inosithin- soyabean. Partial thromboplastin . Do not activate the extrinsic pathway which require complete tissue thrombo plastin.
- 14. APTT PTT is used to detect factor deficiency , screen for lupus anti coagulant Monitor heparin anti coagulation. More sensitive to deficiency of VIII and IX. Yields abnormal results if any factor level is < than 15-30% of normal. PTT may be shortened by a high level of any single factor. m/c is factorVIII.
- 15. APTT Contact activation was provided by the glass tube. Activators - ellagic acid, particulate silicates such as celite or kaolin. No significant differences between adult and children between 7-17 years. Shortened PTT Values is an independent risk factors for death, thrombosis ,bleeding and morbidity.
- 16. PROTHROMBIN TIME : Extrinsic and common path way. Tissue factor, factor VII,X,V, prothrombin, fibrinogen. Plasma is recalcifed in the presence of tissue factor. Independent of platelet count. PT is used for controlling anti coagulant therapy . More sensitive to deficiency of VII and X.
- 17. Prothrombin time Children between 7-17 years have PT value 1 second longer than adults. Use INTERNATIONAL NORMAL RATIO. STYPVEN time- Russel viper venom directly initiate coagulation with out factor VII. Used to differentiate factorVII deficiency from factor- X deficiency.
- 18. Thrombin time: When thrombin is added to plasma the time required for clot formation is a measure at which fibrin forms. Abnormal value when fibrinogen level is <70 to 100 mg/dl. Prolonged by heparin . Prolonged in qulitatively abnormal fibrinogen, elevated FDP, paraproteinemias, hyper fibrinogenemias. REPTILASE CLOTTING TIME- un affected by heparin.
- 19. D-DIMERS and FDP: FDP results from proteolytic cleavage of fibrin by plasmin. Increased in DIC and fibrinolysis. RA factor or residual fibringen may yield false positive results. D-DIMER- specific fibrin degradation product. DDE- TRIMER . UN POLYMERISED FIBRIN MONOMER.
- 20. UREA CLOT LYSIS ASSAY : FACTOR XIII assay . XIII Stabilises fibrin. Deficiency leads to premature clot lysis. Screening test. Abnormal results should be confirmed by quantitative measurements of XIII.
- 21. TESTS FOR FIBRINOLYSIS EUGLOBULIN CLOT LYSIS TIME : Plasma euglobulin contains plasminogen activators and fibrinogen. Rate of lysis of a fibrin clot prepared from euglobin fraction is a measure of plasminogen activators. EACA can inhibit plasminogen activators but not free plasmin. Shortened euglobulin lysis time in presence of EACA indicated presence of free plasmin.
- 22. Bio assays for coagulation factors Extent to which an unknown sample corrects the abnormality in plasma with a known deficiency is proportional to the content of the deficient factor in the sample. Measured in units or percentage of normal. Normal- 50-150 units/dl or 50-150% of normal. Factor V, VIII, X , prothrombin.
- 23. Tests for inhibitors of coagulation Mixing studies or inhibitor screens. Small amount of patient’s plasma if contains inhibitors of coagulation will impair coagulation in normal samples. Based on PT or APTT. HEPARIN presence can be confirmed by thrombin time or reptilase time, or correction with protamine sulphate.
- 24. Automated coagulation methods Thrombo elasto graph- demonstrates changes during blood coagulation and fibrinolysis. Used in surgical settings. Activated clotting time- whole blood clotting assay. Used to monitor intrinsic pathway. In cardio pulmonary bye pass, dialysis, cardiac catheterisation.
- 25. Chromogenic and flurogenic methods Artificial substances when cleaved by coagulation factors release chromogenic or fluroscopic peptides. Prothrombin, VII, IX, X, anithrombin, heparin, plasmin. More precise and less time consuming. Used mainly in research and large reference labs.
- 26. Evaluation of the patient History Physical Examination Laboratory Evaluation
- 27. History Are you a bleeder? surgical challenges accidents & injuries dental extractions menstrual history
- 28. History Generalized haemostatic defect or local defect Bleeding from multiple sites, spontaneous bleeding or excessive bleeding after injury Inherited defect or acquired Family H/O bleeding disorder, age of onset of disease or any other event ppting. the bleeding
- 29. Is Bleeding suggestive of – Vascular, Platelet or coagulation disorder Vascular /platelet disorders – Easy bruising , spontaneous bleeding from small vessels esp into skin – Purpura and echymosis . Mucous membrane bleeding – Epistaxis, mouth –gums and Menorrhagia. Coagulation disorders – Hemarthrosis, muscle bleeds, bleeding after injury or surgery
- 30. Does it sound genetic? duration of bleeding history congenital v. acquired family history examine pedigree determine inheritance
- 31. Medical History liver disease renal disease malignancies poor nutrition (Vit. K or C deficiency)
- 32. FIVE DRUGS THAT INTERFERE WITH HEMOSTASIS ASPIRIN ANTICOAGULANTS ANTIBIOTICS ALCOHOL ANTICANCER
- 33. Laboratory Assessment Guided by history Screening tests PT aPTT platelet count fibrinogen thrombin time
- 34. Partial Thromboplastin Time (PTT) Prothrombin time (PT) Intrinsic pathway Extrinsic pathway Common pathway Thrombin time Thrombin Surface activating agent (Ellagic acid, kaolin) Phospholipid Calcium Thromboplastin Tissue factor Phospholipid Calcium Fibrin clot Fibrin Clot
- 35. Initial Evaluation of a Bleeding Patient - 1 Normal PT Normal PTT Consider evaluating for: Mild factor deficiency Monoclonal gammopathy Abnormal fibrinolysis Platelet disorder ( 2 anti-plasmin def) Vascular disorder Elevated FDPs Urea solubility Normal Abnormal Factor XIII deficiency
- 36. Initial Evaluation of a Bleeding Patient - 2 Normal PT Abnormal PTT Test for factor deficiency: Isolated deficiency in intrinsic pathway (factors VIII, IX, XI) Multiple factor deficiencies (rare) Repeat with 50:50 mix 50:50 mix is normal 50:50 mix is abnormal Test for inhibitor activity: Specific factors: VIII,IX, XI Non-specific (anti-phospholipid Ab)
- 37. Initial Evaluation of a Bleeding Patient - 3 Abnormal PT Normal PTT Test for factor deficiency: Isolated deficiency of factor VII (rare) Multiple factor deficiencies (common) (Liver disease, vitamin K deficiency, warfarin, DIC) Repeat with 50:50 mix 50:50 mix is normal 50:50 mix is abnormal Test for inhibitor activity: Specific: Factor VII (rare) Non-specific: Anti-phospholipid (rare)
- 38. Initial Evaluation of a Bleeding Patient - 4 Abnormal PT Abnormal PTT Test for factor deficiency: Isolated deficiency in common pathway: Factors V, X, Prothrombin, Fibrinogen Multiple factor deficiencies (common) (Liver disease, vitamin K deficiency, warfarin, DIC) Repeat with 50:50 mix 50:50 mix is normal 50:50 mix is abnormal Test for inhibitor activity: Specific : Factors V, X, Prothrombin, fibrinogen (rare) Non-specific: anti-phospholipid (common)
- 39. Laboratory Evaluation of Bleeding Overview CBC and smear Platelet count Thrombocytopenia RBC and platelet morphology TTP, DIC, etc. Coagulation Prothrombin time Extrinsic/common pathways Partial thromboplastin time Intrinsic/common pathways Coagulation factor assays Specific factor deficiencies 50:50 mix Inhibitors (e.g., antibodies) Fibrinogen assay Decreased fibrinogen Thrombin time Qualitative/quantitative fibrinogen defects FDPs or D-dimer Fibrinolysis (DIC) Platelet function von Willebrand factor vWD Bleeding time In vivo test (non-specific) Platelet function analyzer (PFA) Qualitative platelet disorders and vWD Platelet function tests Qualitative platelet disorders
- 40. Liver Disease Decreased synthesis of II, VII, IX, X, XI, and fibrinogen Prolongation of PT, aPTT and Thrombin Time Often complicated by Gastritis, esophageal varices, DIC
- 41. Lab Results in Hemophilia, VWD and Vit K Def Haemophilia V W Disease Vit K Deficiency Bleeding Time Normal Increased Normal PT Normal Normal Increased APTT Increased + Increased ± Increased V111 levels Decreased ++ Decreased Normal vWF levels Normal Decreased Normal
- 42. Hemophilia A Hemophilia B Von Willebrand Disease Inheritance X linked X linked Autosomal dominant Factor deficiency VIII IV VWF Bleeding site(s) Muscle,joint Surgical Muscle ,joint Mucous Skin Prothrombin time Normal Normal Normal Activated PTT Prolonged Prolonged Prolonged Bleeding time Normal Normal Prolonged or normal Factor VIII Low Normal Normal VWF Normal Normal Low Factor IX Normal Low Normal Platelet aggregation Normal Normal Normal
- 43. Coagulation factor deficiencies Summary Sex-linked recessive Factors VIII and IX deficiencies cause bleeding Prolonged PTT; PT normal Autosomal recessive (rare) Factors II, V, VII, X, XI, fibrinogen deficiencies cause bleeding Prolonged PT and/or PTT Factor XIII deficiency is associated with bleeding and impaired wound healing PT/ PTT normal; clot solubility abnormal Factor XII, prekallikrein, HMWK deficiencies do not cause bleeding
- 44. Summary
- 45. Summary Hemostatic Disorders BT Plt PT PTT Vascular Dis - - - - PLT Disorder - - - - Factor 8/9 *Congenital - - - Vit K / Liver *Acquired - - - Combined (DIC) -
- 46. Tests are normal-Now what? simple purpura senile purpura Factor XIII deficiency alpha-2-antiplasmin deficiency mild factor deficiency amyloidosis vascular disorders
- 47. Still more? Hereditary hemorrhagic telangiectasia scurvy Ehlers-Danlos syndrome Henoch-Schonlein purpura the un-diagnosable fibrinolytic defect
- 48. Thank you
Editor's Notes
- #5: April 4, 1998 4 Approach to Bleeding
- #27: April 4, 1998 2 Approach to Bleeding
- #28: April 4, 1998 3 Approach to Bleeding
- #31: April 4, 1998 5 Approach to Bleeding
- #32: April 4, 1998 6 Approach to Bleeding
- #34: April 4, 1998 8 Approach to Bleeding
- #47: April 4, 1998 25 Approach to Bleeding
- #48: April 4, 1998 26 Approach to Bleeding