G-medicine

• Hemostasis


  The normal response of the body to stop bleeding and loss of blood, keeping the blood within a damaged blood vessel
• Elements of hemostasis


  • Vessel wall
  • Platelets
  • Coagulation system (Clotting system)
  • Fibrinolytic system (Fibrinolysis)
• Mechanism of hemostasis


  1. Vascular spasm

  2. Platelet plug formation

  3. Blood coagulation or blood clotting

  4. Fibrinolytic system (Fibrinolysis)
• Successful primary hemostasis


  • Adequate vascular response
  • Adequate platelet number
  • Adequate platelet function
  • Adequate level of the Von Willebrand's Factor (factor VIII)
• Secondary hemostasis (fibrin clot)


  Through coagulation cascade
• Tertiary hemostasis


  1. Formation of plasminogen and then plasmin which is the main enzyme responsible for fibrinolysis

  2. Activation of fibrinolysis is triggered by the presence of fibrin, and tissue-type plasminogen activators (t-PA) at the site of fibrin formation

  
• Anti-fibrinolytic drugs


  Aminocaproic acid and tranexamic acid
• Achieving hemostasis other than naturally

  1. Direct pressure

  2. Ligation

  3. Hemostatic agent (chemical and/or mechanical)
• Clinical assessment of hemostasis


  • History: Family history, coexisting illness, drug therapy
  • Examination: Bruising, purpura, telangiectasia, swollen joints/hemarthrosis, hepatomegaly, splenomegaly
• Investigations for hemostasis

  • Platelet count
  • Bleeding time (BT)
  • Prothrombin time (PT)
  • Partial thromboplastin time (PTT)
  • Thrombin time (TT)
• Vessel wall abnormalities


  Hereditary hemorrhagic telangiectasia
• Platelet disorders


  • Thrombocytopenia (low platelets)
  • Increased platelet destruction; immunological (idiopathic thrombocytopenic purpura ITP), splenomegaly or disseminated intravascular coagulopathy (DIC)
• Clinical features of platelet deficiency

  • Easy bruising and easy bleeding, petechia, ecchymosis on oral mucosa and skin, postoperative hemorrhage
• Hemophilia A


  1. linked recessive disorder, factor VIII deficiency
• Hemophilia B


  Caused by a deficiency of factor IX, also an X-linked condition
• Hemophilia C


  Inherited as an autosomal dominant disorder, factor XI deficiency
• Warfarin


  Vitamin K antagonist, prolongs PT and INR
• Aspirin


  Most commonly used antiplatelet agent, inhibits platelet aggregation
• Clopidogrel (Plavix)


  Commonly used antiplatelet agent, prevents platelet aggregation
• Heparin


  Parenteral anticoagulant, blocks the conversion of fibrinogen to fibrin, reversed by protamine sulfate
• Vitamin K deficiency


  Causes decreased levels of factors II, VII, IX, and X, protein C and protein S
• Disseminated intravascular coagulation (DIC)

  Generation of intravascular fibrin clots leading to multi-organ failure, with simultaneous coagulation factor and platelet consumption causing bleeding
• Liver disease


  Causes reduced synthesis of coagulation factors or thrombocytopenia, cholestatic jaundice reduces vitamin K absorption
• Renal disease


  Advanced renal failure is associated with platelet dysfunction and bleeding
• Scurvy


  Vitamin C deficiency affects the normal synthesis of collagen and results in a bleeding disorder
• Oral findings in bleeding disorders

  • Petechiae or ecchymosis in oral mucosa, spontaneous gingival bleeding, brown deposits on teeth, higher incidence of dental caries and periodontal diseases
• Dental management of bleeding disorders

  Consult physician, factor replacement, use of local hemostatic agents and techniques, careful use of anesthesia and pain management, oral surgery, periodontal procedures, restorative and endodontic procedures, prosthodontic procedures, orthodontic procedures
• Medications affecting hemostasis


  ASA and NSAIDs can increase the effect of warfarin, certain antibiotics and antifungals also potentiate warfarin