Clinical Relevance of Hemostasis David Lillicrap Dept Pathology & Molecular Medicine
The Hemostatic Balance Bleeding Clotting
EASY BRUISING How easy? Where are the bruises? How many bruises? How large are the bruises? How frequent?
OTHER MUCOCUTANEOUS BLEEDING Epistaxis How Frequent? Duration of bleeding? Both nostrils? Gum Bleeding
Other Mucocutaneous Bleeding Menorrhagia Duration Amount of bleeding Pads/ Tampons “Flooding” Clots Anemia/ Iron replacement
MUSCULOSKELETAL BLEEDING Joint bleeds (hemarthroses) Soft Tissue/Muscle Bleeds
GASTROINTESTINAL BLEEDING GENITOURINARY BLEEDING Beware intrinsic lesions
PREVIOUS CHALLENGES TO THE HEMOSTATIC SYSTEM Surgery Tonsillectomy Wisdom teeth extraction In contrast - minor abdominal surgery may be uneventful
FAMILY HISTORY X-Linked recessive: Hemophilias Autosomal dominant: VWD Autosomal recessive: Others
MEDICATION HISTORY Anticoagulants Coumadin Heparin Platelet Antagonists
MEDICATION HISTORY Platelet Antagonists Aspirin NSAIDS Alcohol Antihistamines Beta blockers Nitrates Calcium blockers
ACQUIRED DISORDERS OF COAGULATION Does the patient have symptoms or signs of liver disease? Is there a reason why the patient should be vitamin K deficient? Malnutrition Biliary obstruction Broad Spectrum antibiotics
ACQUIRED DISORDERS OF COAGULATION Does the patient have a co-existent systemic disease? Sepsis Disseminated malignancy Obstetric problems Burns Snake Bite
Which one of the following proteins is NOT involved in platelet plug formation? • Von Willebrand Factor. • Collagen • Glycoprotein Ib • Prothrombin
Which one of the following functions is NOT performed by von Willebrand Factor? • Stabilization of FVIII in plasma. • Attachment of platelets to the subendothelium. • Promotion of platelet-platelet interaction. • Activation of Factor X.
FVIII - VWF Stabilizing complex in plasma
Physiological protein-based hemostasis is initiated by which one of the following phenomena? • Thrombin generation. • Fibrinogen binding to platelets. • Activation of FXI • Exposure of tissue factor to FVIIa
The prothrombin time (PT) coagulation test evaluates which one of the following hemostatic pathways? • The intrinsic pathway. • Conversion of fibrinogen to fibrin. • The extrinsic pathway. • Factor X activation.
Extrinsic Pathway (prothrombin time - PT)
Which one of the following coagulation proteins is NOT evaluated by the Activated Partial Thromboplastin time (aPTT)? • Factor VII. • Factor VIII. • Factor XI. • Factor IX.
Intrinsic Pathway (aPTT)
The thrombin clotting time measures which one of the following coagulation reactions? • Activation of Factor X. • Conversion of Prothrombin to thrombin. • Factor IX activation. • Conversion of fibrinogen to fibrin.
Which one of the following coagulation proteins is not a serine protease enzyme? • Factor X • Factor IX • Factor VIII • Factor XI
Which one of the following proteins is NOT a natural anticoagulant? • Protein C. • Protein S • Factor XII. • Antithrombin.