Lecture 7 - PDF

Normocytic, normochromic anemia: Lecture 6: Hemolytic Anemia in general Lecture 7: 1. Hereditary Spherocytosis: RBCs Membrane defects 2. Glucoze-6-Phosphate- Dehydrogenaze (G6PD) deficiency RBCs Metabolic defects. 3. Hemoglobinopathies Lecture 8: Sickle cell anemia and Thalassaemias...

Normocytic, normochromic anemia: Lecture 6: Hemolytic Anemia in general Lecture 7: 1. Hereditary Spherocytosis: RBCs Membrane defects 2. Glucoze-6-Phosphate- Dehydrogenaze (G6PD) deficiency RBCs Metabolic defects. 3. Hemoglobinopathies Lecture 8: Sickle cell anemia and Thalassaemias 0 0  To know spherocytes and the difference between them and normal Biconcave red cells. To review red cell membrane constituents. To know H.S as one of the Hemolytic anemias. To know the lab. Diagnosis of H.S and the principle of Osmotic fragility Test. 0 What is Hereditary Spherocytosis? 0 Etiolog y 0 RBCs breakdown 0 0 0 0 The osmotic fragility test 0  Normal results in osmotic fragility test Isotonic Hypotonic Hpertonic solutions: solutions: solutions: Cells will Cells Cells remain will swell will shrink 0 0  The blood Film Anisocytosis = cells vary in size Spherocytes.(less in diameter, greater thickness, no central pallor). Polychromatic cells. 0  When polychromatic RBCs are Polychromatic red stained with a supravital dye cells are larger than (new methylene blue or cresyl mature erythrocytes violet) ribosomes clump to form and still contain a blue stained granulars called ribosomes and reticulum. These are called mitochondria, giving reticulocytes. the cell a blue tint. 0 Supravital stain of blood from a patient with hemolytic anemia. The reticulocytes are the cells with the dark blue dots and curved linear structures (reticulum) in the cytoplasm 0 Scanning electron micrograph of a Scanning electron micrograph of a spherocyte. It is normal biconcave erythrocyte smaller, round, and lacks concavities 0  G6PD Deficiency (Glucose 6 phosphate dehydrogenase Deficiency) Objectives To review the role of G6PD enzyme, and the red cell metabolism. To define G6PD deficiency as a hemolytic anemia. List the lab. Findings in G6PD deficiency.  Enzyme defects: Glucose 6- Phosphate Dehydrogenase Deficiency  What is G6PD? FUNCTION OF G6PD What happens in G6PD deficiency? What is favism? CLINICAL features  Lab. Diagnosis 1. Between crisis, blood count is normal. 2. During crisis, features of intravascular hemolysis. 3. Reticulocytosis during hemolysis. 4. Blood film: Bit/Blister red blood cells 5. Heinz bodies 6. Screening Tests for G6PD Deficiency 7. Enzyme assay 4. Blood film examination: - Contracted & fragmented cells: Bite/Blister cells : loss of cytoplasm with separation of remaining Hb from cell membrane. arrow indicates a “bite” cell, or keratocyte - When the red cell membrane around the bite repairs, a blister- like structure forms, hence the term blister cell. arrows indicate “blister cells,” and arrowheads irregularly contracted cells 5. Heinz bodies: Heinz bodies are red cells’ inclusions composed of oxidized denatured hemoglobin. Heinz bodies appear as small round inclusions within the red cell, though when stained with Romanowsky stains they may appear as projections from the cell. They appear more clearly when supravitally stained 6. Screening Tests for G6PD Deficiency  7. Enzyme assay Spectrophotometric enzyme assays. The activity of the enzyme is assayed by following the rate of production of NADPH, which, unlike NADP, has a peak of UV light absorption at 340 nm. Variant types of Haemoglobinopathies 0 What are hemoglobinopathies? Classification 1. Variant Hemoglobins Common variants Hb S Hb Lepore Hb C Hb M Hb E Hb AS Hb D-Punjab Hb AC Hb O-Arab Hb ADPunjab Hb G-Philadelphia Hb AE Hb Hasharon Hb AOArab Hb Korle-Bu 2. Thalassaemias 3. Hereditary Persistence of Foetal Haemoglobin (HPFH)  The abnormality in Haemoglobinopathies may occur in the heterozygous or the homozygous form. Zygosity refers to the similarity of genes for a trait (inherited characteristic). If both genes are the same, the person is homozygous for the trait. If both genes are different, the person is heterozygous for that trait Laboratory diagnosis