Disorders of Hemostasis PDF

Disorders of Hemostasis Thromboembolic conditions thrombi and emboli thrombus: clot that develops and persists in unbroken blood vessel May block circulation, leading to tissue death embolus: thrombus freely floating in bloodstream embolism:...

Disorders of Hemostasis Thromboembolic conditions thrombi and emboli thrombus: clot that develops and persists in unbroken blood vessel May block circulation, leading to tissue death embolus: thrombus freely floating in bloodstream embolism: embolus obstructing a vessel ex: pulmonary or cerebral emboli risk factors: atherosclerosis, inflammation, slowly flowing blood or blood stasis from immobility © McGraw Hill, LLC 55  Blood Grouping Transfusion: transfer of blood or blood components from one individual to another Infusion: introduction of fluid other than blood transfusion success determined by antigens (agglutinogens) on surface of RBCs Antibodies (agglutinins) can bind to RBC antigen → agglutination or hemolysis of RBCs Groups: ABO, Rh, Lewis, Duffy, MNSs, Kidd, Kell, and Lutheran © McGraw Hill, LLC 56  ABO Blood Groups © McGraw Hill, LLC 57  Agglutination Reaction a) no agglutination reaction © McGraw Hill, LLC 58  Agglutination Reaction b) Agglutination reaction © McGraw Hill, LLC 59  Rh Blood Group Rh-positive: D antigen present on surface of RBCs (very common) Rh-negative: lack D antigen (rarest blood type is AB-) Hemolytic disease of the newborn (HDN) Rh+ fetus & Rh- mother late in pregnancy Rh antigens of fetus cross placenta (through tear in placenta or during delivery) mother creates anti-Rh antibodies (primary response) 2nd Rh+ pregnancy can initiate HDN potentially fatal to fetus since fetal RBCs destroyed by mother’s Abs RhoGAM injection for mother contains antibodies against Rh antigens Abs attach to fetal R B Cs and inactivate antigens prevents sensitization to fetal RBCs by mother’s immune system © McGraw Hill, LLC 60  Hemolytic Disease of the Newborn (HDN) © McGraw Hill, LLC 61  Diagnostic Blood Tests Blood typing determines ABO and Rh blood types. Red cells tested against antibodies Crossmatch: donor blood cells mixed with recipient’s serum and vice versa; look for agglutination. Jarun011/iStock/Getty Images © McGraw Hill, LLC 62  Hematocrit Complete blood count (CBC) Red blood count: number of RBCs/ μL of blood Hemoglobin measurement: g of hemoglobin / 100 mL of blood (for males = 14 - 17 g/100 mL; females = 12 - 15 g/100 mL) Hematocrit measurement: % of blood that is RBCs (look for normocytes, microcytes & macrocytes) White blood cell count: 4,500 to 11,000 / μL of blood © McGraw Hill, LLC 63  Other Tests Differential white blood count: determines % of each of WBCs Normal values: Neutrophils: 55 - 70% Lymphocytes: 20 - 40% Monocytes: 2 - 8% Eosinophils: 1 - 4% Basophils: 0.5 - 1% Clotting assessment: Platelet count: 150,000 - 400,000/ μL reduced = thrombocytopenia Prothrombin time measurement: how long it takes for blood to start clotting (normal = 9 to 12 sec) thromboplastin added to whole plasma to test Blood chemistry: composition of materials dissolved or suspended in plasma used to assess functioning of many body systems © McGraw Hill, LLC 64  Diseases & Disorders of Blood: Sickle-Cell Anemia mutated hemoglobin 1 amino acid incorrect in a β globin chain of 146 amino acids RBCs become crescent shaped when O2 levels are low (during exercise) misshapen RBCs rupture easily & block small vessels → poor O2 delivery & pain prevalent in people of African malarial belt & their descendants possible benefit: people w/ sickle-cell do not contract malaria kills 1 million / year 2 copies of Hb-S can develop sickle-cell anemia 1 copy leads to milder disease & better chance of surviving malaria © McGraw Hill, LLC 65  Sickle-Cell Anemia treatment: acute crisis treated w/ transfusions or inhaled nitric oxide prevention of sickling: hydroxyurea induces formation of fetal hemoglobin (does not sickle) stem cell transplants gene therapy nitric oxide for vasodilation © McGraw Hill, LLC 66  Representative Diseases and Disorders of Blood TABLE 19.4 Representative Diseases and Disorders of Blood Condition Description Erythrocytosis Relative erythrocytosis Overabundance of red blood cells due to decreased blood volume, as may result from dehydration, diuretics, or burns Primary Stem cell defect of unknown cause; results in overproduction of red blood cells, granulocytes, and platelets; signs erythrocytosis(polycyth include low erythropoietin levels and enlarged spleen; increased blood viscosity and blood volume can cause clogging of emia vera) the capillaries and hypertension Secondary Overabundance of red blood cells resulting from decreased O2 supply, as occurs at high altitudes, in chronic obstructive erythrocytosis pulmonary disease, and in congestive heart failure; decreased O2 delivery to the kidney stimulates the secretion of erythropoietin, resulting in increased blood viscosity and blood volume that can cause clogging of the capillaries and hypertension Anemia Deficiency of hemoglobin in the blood Iron-deficiency anemia Caused by insufficient intake or absorption of iron or by excessive iron loss; leads to reduced hemoglobin production Folate-deficiency Folate is important in DNA synthesis; inadequate folate in the diet results in a reduction in cell division and therefore a anemia reduced number of red blood cells Pernicious anemia Secondary folate-deficiency anemia caused by inadequate amounts of vitamin B12, which is important for folate synthesis Hemorrhagic anemia Results from blood loss due to trauma, ulcers, or excessive menstrual bleeding Hemolytic anemia Occurs when red blood cells rupture or are destroyed at an excessive rate; causes include inherited defects, exposure to certain drugs or snake venom, response to artificial heart valves, autoimmune disease, and hemolytic disease of the newborn Aplastic anemia Caused by an inability of the red bone marrow to produce red blood cells, usually as a result of damage to stem cells after exposure to certain drugs, chemicals, or radiation Thalassemia Autosomal recessive disease that results in insufficient production of globin part of hemoglobin Leukemia Cancers of the red bone marrow in which one or more white blood cell types is produced; cells are usually immature or abnormal and lack normal immunological functions © McGraw Hill, LLC 67  Representative Diseases and Disorders of Blood 2 TABLE 19.4 Representative Diseases and Disorders of Blood Condition Description Thrombocytopenia Reduction in the number of platelets that leads to chronic bleeding through small vessels and capillaries; causes include genetics, autoimmune disease, infections, and decreased platelet production resulting from pernicious anemia, drug therapy, radiation therapy, or leukemias Clotting Disorders Disseminated Clotting throughout the vascular system, followed by bleeding; may develop when normal regulation of clotting by intravascular anticoagulants is overwhelmed, as occurs due to massive tissue damage; also caused by alteration of the lining of coagulation (DIC) the blood vessels resulting from infections or snakebites Von Willebrand disease Most common inherited bleeding disorder; platelet plug formation and the contribution of activated platelets to blood clotting are impaired; treatments are injection of von Willebrand factor or administration of drugs that increase von Willebrand factor levels in blood, which helps platelets adhere to collagen and become activated Hemophilia Genetic disorder in which clotting is abnormal or absent; each of the several types results from deficiency or dysfunction of a clotting factor; most often a sex-linked trait that occurs almost exclusively in males Infectious Diseases of Blood Septicemia (blood Spread of microorganisms and their toxins by the blood; often the result of a medical procedure, such as insertion poisoning) of an intravenous tube; release of toxins by bacteria can cause septic shock, producing decreased blood pressure and possibly death Malaria Caused by a protozoan introduced into blood by Anopheles mosquito; symptoms include chills and fever produced by toxins released when the protozoan causes red blood cells to rupture Infectious Caused by Epstein-Barr virus, which infects salivary glands and lymphocytes; symptoms include fever, sore throat, mononucleosis and swollen lymph nodes, all probably produced by the immune system response to infected lymphocytes Acquired Caused by human immunodeficiency virus (HIV), which infects lymphocytes and suppresses immune system immunodeficiency syndrome (AIDS) © McGraw Hill, LLC 68