Presentation on theme: "Chapter 12 Disorders of Hemostasis"— Presentation transcript:
1 Chapter 12 Disorders of Hemostasis Essentials of PathophysiologyChapter 12 Disorders of Hemostasis
2 PRE LECTURE QUIZ (TRUE/FALSE) Platelets are also known as leukocytes.Idiopathic thrombocytopenic purpura (ITP) is an autoimmune disorder that affects the normal function and formation of platelets.Disseminated intravascular coagulation is a condition that results in massive systemic bleeding, but coagulation function remains normal.The use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) has been identified as a cause of impaired platelet function.Bleeding can occur as a result of a decrease in the number of circulating platelets or because of impaired platelet function.
3 PRE LECTURE QUIZ_________________ is the orderly, stepwise process for stopping bleeding that involves vasospasm, formation of a platelet plug, and development of a fibrin clot.A decrease in the number of circulating platelets is known as _________________________.Hemophilia A is an X-linked recessive disorder that involves a deficiency of factor _________________.________________ disorders are caused by defects associated with platelets, coagulation factors, and vessel integrity.Vitamin _______________, a fat-soluble vitamin that is continuously being synthesized by intestinal bacteria, is necessary for normal activity of factors VII, IX, and X and prothrombin.Bleeding K Hemostasis thrombocytopeniaVIII
5 Platelets (Thrombocytes) ThrombopoietinMade in liver, kidney, smooth muscle, bone marrowMegakaryocytes formed in bone marrowBreak apart to form many plateletsPlatelets live 8–9 days in circulationMany are stored in spleenReleased when needed
7 QuestionAll but which of the following are true about platelets?An enzyme called erythropoietin stimulates their production.They are made from megakaryocytes.They originate from the bone marrow.They are stored in the spleen.
8 AnswerAn enzyme called erythropoietin stimulates their production.Rationale: Erythropoietin stimulates the production of RBCs (erythrocytes). The word literally means erythrocyte production. Platelet formation is stimulated by thrombopoietin (thrombus/clot production).
10 Mediators of Hemostasis Chemicals produced by plateletsReleased at an injury to:Start clotting by reacting with blood proteinsHelp platelets stick togetherStimulate wound healingHelp platelets stick to vessel wallConstrict blood vessels
11 Coagulation FactorsPlasma proteinsMost are synthesized by livervon Willebrand factor made by endotheliumCirculate as inactive procoagulation factorsCalcium
12 QuestionWhat is the effect of von Willebrand disease on the platelets?Increased platelet aggregationDecreased platelet aggregationIncreased platelet formationDecreased platelet formation
13 AnswerDecreased platelet aggregationRationale: Von Willebrand disease is the most common hereditary bleeding disorder. It is caused by a deficiency or defect in vWF (which carries a clotting factor). The result of less clotting factor is an inability to clot.
15 Cyclooxygenase Enzymes (COX) Produce Mediators of Hemostasis Celebrex is a drug that blocks COX-2Given to block inflamationPeople taking Celebrex develop increased TXA2 levelsWhat problems might they have?arachidonicacidCOX-1COX-2thromboxane A2ProstacyclinMacrophage Activation & Inflamation mediationNSAIDs inhibit both COX 1 &2COX 1 is needed for intestinal mucosaProblems here?
16 Intrinsic and Extrinsic Pathways Common Pathway
17 Platelets Activated platelets Platelet aggregate with fibrin threads Non activated plateletPlatelet aggregate with fibrin threads
19 ScenarioA man had a stroke and the doctor gave him tissue plasminogen activator (TPA).Why? What is the doctor trying to accomplish?One of the man’s relatives wondered why they did not give him heparin or warfarin insteadWhat is the difference? Why might TPA be more appropriate?
21 QuestionTrue or False. Hypercoagulability states increase the risk of thrombus formation.
22 AnswerTrue Rationale: Hyper- as a prefix means “over” or “too much.” Coagulation/coagulability means “clotting/the ability to clot.” Hypercoagulability means “increased ability to clot or form thrombi.”
23 A woman with lupus develops breast cancer. Scenario:A woman with lupus develops breast cancer.She is given radiation therapyShe begins to develop nosebleeds and bruisingHer menstrual period is abnormally heavyQuestion:Why did this happen?
24 Platelet Disorders Decreased platelet levels (thrombocytopenia) Decreased productionIncreased destructionPlatelets used up in forming clotsImpaired platelet function