Hematologic Systems PDF

Chapter 17: Hematologic Systems Hematologic system: causes of microcytic anemia ○ Decreased hemoglobin production: Iron deficiency anemia Sideroblastic anemia Lead poisoning Thalassemia Anemia of Chronic disease LISAT Microcytic Anemia : Iron deficiency anemia ○ Iron Absorbed in the duodenum Carried...

Chapter 17: Hematologic Systems Hematologic system: causes of microcytic anemia ○ Decreased hemoglobin production: Iron deficiency anemia Sideroblastic anemia Lead poisoning Thalassemia Anemia of Chronic disease LISAT Microcytic Anemia : Iron deficiency anemia ○ Iron Absorbed in the duodenum Carried in blood by transferrin Stored in ferritin and hemosiderin Found in hemoglobin (Hb) and myoglobin The ion in the center of heme (O2 carrying molecule) ○ Irone (Fe) Increased iron = increased heme = increase in O2 carrying capacity = increase in oxygen saturation Decreased iron = decreased heme = decrease in O2 carrying capacity = decrease in oxygen saturation ○ Decreased iron/ decreased oxygen Fatigue, weakness, pallor SOB, DOE, increased respirations Koilonychia ‘ spoon nails’ PICA Increased heart rate → palpitations Glossitis Gastric atrophy and achlorhydria ○ Iron studies Serum iron (Fe) is circulating iron Serum ferritin is stored iron Total iron binding capacity (TIBC) is the “capacity to bind” Transferrin saturation is the serum Fe/ TIBC % Iron deficiency → decreased saturation of ferritin binding sites → increased Total iron binding capacity Iron overload → increased saturation of ferritin binding sites → decrease in total iron binding capacity Microcytic anemia: sideroblastic anemia ○ Sideroblastic anemia: Genetic disorder (or part of myelodysplastic syndrome) Bone marrow produces ringed sideroblasts (rather than healthy RBCs) Iron is present but cannot be incorporated into hemoglobin Sideroblasts are nucleated erythroblasts (precursors to erythrocytes) with granules of iron in the mitochondria surrounding the nucleus Ringed sideroblasts are iron laden mitochondria form ring around nucleus ○ Low: RBC, Hb, HCT, MCV, TIBC, Transferrin saturation ○ High: Iron, Ferritin ○ RBC dimorphism ○ RBC stippling ○ Iron deficient anemia→ Low: MVC, Fe, Ferritin High: TIBC ○ Sideroblastic anemia → Low: MVC & TIBC High: FE & Ferritin Microcytic anemia: thalassemia ○ Thalassemia → “blood of the sea” ○ Inherited AR disorder ○ More common in mediterranean area ○ Causes abnormal Hb formation ○ Abnormal formation = increased destruction of RBCs ○ May confer protection against malaria ○ Two major types: alpha and beta Microcytic anemia: anemia of chronic disease ○ Decreased hemoglobin production ○ Impaired erythropoiesis: Decreased production of EPO Decreased marrow response to EPO ○ Impaired intracellular iron metabolism: Iron retained by reticuloendothelial cells ○ Liver: Increased hepatic synthesis of hepcidin → increased hepcidin → inhibits iron release from RES ○ Kidneys: Inhibits erythropoietin release → decreased erythropoietin ○ Bone marrow: Inhibited erythroid proliferation is caused by decreased erythropoietin ○ Hemophagocytosis Hematologic system: Causes of macrocytic anemia ○ Decreased nuclear maturation: Folic acid anemia Vitamin B12 deficiency anemia Pernicious anemia (decreased intrinsic factor) Alcoholism Liver disease Hypothyroidism Medications Macrocytic anemia: Megaloblastic anemia ○ Megaloblastic anemia Abnormally large RBCs that don’t function appropriately Due to deficiency of B12 (cyanocobalamin) or folate (B9) Etiology: Poor diet → decreased leafy green vegetables (folate deficiency) or vegan (B12 deficiency) Alcoholism Medications (anticonvulsants, PPIs) Congenital (rare) Clinical presentation Fatigue, SOB, DOE, lethargy, muscle weakness Glossitis (sore red tongue), mouth ulcers neurologic - neuropathy; tingling/burning/ pins and needles (paresthesia) Psychiatric → irritability, depression, dementia/memory loss Macrocytic anemia: pernicious anemia ○ Pernicious = exceedingly harmful, in a gradual way ○ Pernicious anemia Inability to absorb B12 due to absence of intrinsic factor (IF) Intrinsic factor – glycoprotein secreted by gastric parietal cells Binds to B12– for absorption of B12 at terminal ileum Intrinsic factor deficiency – chronic gastritis/atrophic gastritis, gastrectomy Autoimmune condition (antibodies attack gastric parietal cells) ○ Test: anti-IFAB (intrinsic factor antibody test) + Test= pernicious anemia Schilling test– rarely used ○ Treatment: B12 injections, intrinsic factor supplement Note: vitamin C helps absorb iron large doses interfere with absorption of B12 Normocytic Anemia: Hemolysis ○ Hemolysis= heme lysis = rupture of red blood cells ○ May be due to: infections (gram + bacteria; parasites), autoimmune disorders (drug induced hemolytic anemia), and genetic disorders (sickle cell disease; G6PD deficiency) ○ 1. Intrinsic and extrinsic causes Intrinsic: defect of RBC membrane (ex: hereditary Spherocytosis) Defect in Hb production (ex: thalassemia, Sickle cell disease) Defect in RBC metabolism (ex: G6PD deficiency) Extrinsic Immune mediated; hypersplenism; burns; infections; poisoning; runners (foot-strike hemolysis) ○ 2. Intravascular and extravascular hemolysis Intravascular = hemolysis in the vasculature Extravascular= hemolysis occurring in liver, spleen, bone marrow, lymph nodes Hemosiderin deposits in spleen, bone marrow, kidneys, liver Normocytic anemia: sickle cell disease ○ Clinical presentation: anemia, hemolysis (increased bilirubin= jaundice), pain, swelling of hands and feet, bacteria infections ○ Sickle cell crisis is brought on by temperature change, stress, dehydration, high altitude ○ Complications: chronic pain, aseptic bone necrosis, leg ulcers, stroke ○ Treatment: antibiotics, vaccinations, folic acid supplements, pain medications, blood transfusions Chapter 16: Hematologic system Functions of the hematologic system ○ Functions of blood: 1. Transportation Oxygen (from lungs to left side of heart to cells) Carbon dioxide (from cells to right side of the heart to lungs) Hormones (from endocrine glands to cells) Waste products (To kidneys and liver) Nutrients (from GI tract to cells) Immunoglobulins Clotting factors 2. Regulation 3. Protection Function of blood cells ○ Blood =plasma + blood cells ○ Blood cells: Red, white and platelets Erythrocytes (RBCs) ○ Most abundant cells in the body ○ Account for 40-45% of blood volume ○ Biconcave disks with flattened centers ○ No nucleus, can easily change shape ○ Lifespan of 120 days Function: Contain hemoglobin (O2 carrying protein) to ○ Carry O2: lungs → body ○ Carry CO2: body → lungs Leukocytes (WBCs) Thrombocytes (platelets) Physiologic processes: hematopoiesis and Erythropoiesis ○ Hematopoiesis All cells originate from one hematopoietic stem cell RBCs, WBCs, and platelets all come from the same STEM CELL Process originates in the bone marrow Greatest bone marrow activity occurs in… Adults: vertebrae, Sternum, ribs Children: long bones ○ Erythropoiesis Originates in bone marrow Leads to formation of reticulocytes and erythrocytes (RBCs) Stimulated by erythropoietin (EPO) that is produced in the kidney EPO produced in response to blood flow and levels of oxygen Hematologi system: anemia ○ Anemia, from the greek “lack of blood” Most common blood disorder Reduction in number of red blood cells or hemoglobin Reduced ability to deliver oxygen Onset slow: tiredness, weakness, SOB, headaches, exercise intolerance, DOE Rapid: confusion, synco[e, LOC, increased thirst Causes: Blood loss (trauma, GI loss, …) Decreased RBC production (deficiencies, bone marrow pathologies) Increased RBC breakdown/hemolysis (genetics, infections, autoimmune) Tests: Complete blood count (CBC) Serum ferritin, serum B12 Reticulocyte count Blood smear Bone marrow aspirate