Disorders of Hemostasis

1. Thromboembolytic Disorders (undesirable clotting)
   

• thrombus - blood clot in normal blood vessel
• embolus - blood clot/gas bubble floating in blood

• TPA, streptokinase - can dissolve a clot
• aspirin - inhibits Thromboxane formation
• heparin - inhibits thrombin & platelet deposit
• dicumarol - anticoagulant, blocks Vitamin K
  

2. Bleeding Disorders
   

• thrombocytopenia - reduced platelet count; generally below 50,000 per cubic millimeter; can cause excessive bleeding from vascular injury
  
• impaired liver function - lack of procoagulants (Clotting Factors) that are made in liver
  

• vitamin K - essential for liver to make Clotting Factors for coagulation
  

3. Hemophilias - hereditary bleeding disorders that occur almost exclusively in males
   

• hemophilia A - defective Factor VIII (83%)
• hemophilia B - defective Factor IX (10%)
• Genentech, Inc. - now produces genetically engineered TPA and Factor VIII; patients do not need transfusions as often.

Category: Pathology Notes