Blood Disorders 1 PDF

Blood disorders 1 University of Jordan, faculty of medicine Manar Hajeer, MD, FRCPath Subtypes:  Red Cell Disorders (anemia, polycythemia)  White Cell Disorders (neoplastic and nonneoplastic)  Bleeding disorders (thrombocytopenia and coagulation) Red Cell Disorders Ane...

Blood disorders 1 University of Jordan, faculty of medicine Manar Hajeer, MD, FRCPath Subtypes:  Red Cell Disorders (anemia, polycythemia)  White Cell Disorders (neoplastic and nonneoplastic)  Bleeding disorders (thrombocytopenia and coagulation) Red Cell Disorders Anemia  Reduction in the oxygen-transporting capacity of blood, resulting from a decrease in the red cell mass, resulting in tissue hypoxia.  Measured by hemoglobin concentration (Hg) and hematocrit (Hct).  Classification (cause):  Bleeding (blood loss).  Increased red cell destruction (hemolytic anemias)  Decreased red cell production. Anemia and erythropoietin: Hypoxia triggers increased erythropoietin. Compensatory erythroid hyperplasia in BM. In acute bleeding or hemolysis in healthy patient, increased production of red cells 5x to 8x. Increased numbers of newly formed red cells (reticulocytosis). In severe cases, extramedullary hematopoiesis (liver, spleen, and lymph nodes). Exceptions (anemia of renal failure and chronic inflammation) RBC indices:  Hematocrit: percentage of RBCs in blood  MCV: average volume per RBC, in femtoliters (cubic microns)  MCH: average mass of hemoglobin per RBC, in picograms.  MCHC: average concentration of hemoglobin in a given volume of packed RBCs, in grams per deciliter  RDW: variation of RBC volume.  Reticulocytes: Aregenerative anemia (reticulocytopenia), hemolytic anemia (reticulocytosis).  Indices are measured quantitatively or on blood film. Peripheral blood film Classification of anemia (morphology of RBCs)  Size: reflected by MCV (normo, micro, macrocytic)  Color: reflected by MCH (normo, hypochromic)  Shape: reflected by RDW (aniso-poikelocytosis: spherocytes, sickle, schistiocytes) Morphology:  Microcytic: impaired Hg synthesis (iron deficiency, thalassemia)  Macrocytic: impaired maturation (folate or vitamin B12 deficiency)  Normocytic but with abnormal shapes (hereditary spherocytosis, sickle cell disease) Other blood tests to evaluate anemia  Microcytic anemia: Serum iron indices (iron levels, iron-binding capacity, transferrin saturation, and ferritin concentrations)  Hemolytic anemia (Plasma unconjugated bilirubin, haptoglobin, and lactate dehydrogenase levels).  Megaloblastic anemia: (folate and vitamin B12 concentrations)  Abnormal hemoglobin (hemoglobin electrophoresis) Clinical Manifestations  Acute: shortness of breath, organ failure, shock.  Adaptive changes with slow onset anemia:  Increased heart rate (tachycardia)  Increased respiratory rate (tachypnea).  Symptoms worse with pulmonary or cardiac disease. Clinical manifestations  Chronic  Pallor, fatigue.  With hemolysis: jaundice and gallstones  With ineffective erythropoiesis (premature death of marrow erythroid progenitors) >> increase iron absorption from gut >> iron overload, heart and endocrine failure (secondary hemochromatosis)  If severe and congenital (thalassemia and sickle cell anemia): growth retardation, bone deformities due to reactive marrow hyperplasia  Extramedullary hematopoiesis (splenomegaly, hepatomegaly) Jaundice and gallstones with hemolytic anemia. Skeletal deformities and cardiac hemochromatosis ANEMIA OF BLOOD LOSS: HEMORRHAGE (acute and chronic)  Acute bleeding  Massive loss of intravascular volume, leads to cardiovascular collapse, shock and death.  If blood loss exceeds 20% of blood volume, the immediate threat is hypovolemic shock rather than anemia.  Hemodilution achieves full effect 2 to 3 days (dilutional anemia)  Normocytic normochromic anemia with reticulocytosis.  Compensatory rise in erythropoietin level >> increased red cell production (5 to 7 days). Chronic blood loss  Gastrointestinal bleeding (ulcer, hemorrhoids, cancer) and menstruation.  Iron stores are gradually depleted.  Iron deficiency leads to a chronic anemia of underproduction.  Microcytic, hypochromic, with low reticulocytes.