MLAB 1315- Hematology Keri Brophy-Martinez

1. MLAB 1315- HematologyKeri Brophy-Martinez Unit 8: Morphological Changes Associated with Disease

2. MORPHOLOGICAL CHANGES ASSOCIATED WITH DISEASE • Evaluating and reporting anisocytosis (size) and poikilocytosis (shape) • RDW (red cell distribution width) is a measure expressed in percent of the variation in the red cell volume distribution. • Normal range: 11.5-14.0% • Grading scale • Normal slight variation from normal red cell • Slight 5-10% of cells vary in size or shape from normal red cell • 1+ 10-25% of cells vary in size or shape from normal red cell (Few) • 2+ 25-50% of cells vary in size or shape from normal red cell (Moderate) • 3+ 50-75% of cells vary in size or shape from normal red cell (Many) • 4+ >75% of cells vary in size or shape from normal red cell (Marked)

3. Size variations (correlate with MCV and RDW) • Causes of macrocytes • Caused by impaired DNA synthesis which leads to decreased number of cell divisions resulting in a larger red cell • Accelerated erythropoiesis which results in increased reticulocytes (retics are larger than mature red cells). • Causes of microcytes • Impaired hemoglobin synthesis which may be caused by iron problems • Decreased or defective globin synthesis

4. Stain variations • Hypochromia (correlate with MCHC) • 1+ area of central pallor is ½ of cell diameter • 2+ area of central pallor is of cell diameter • 3+ area of central pallor is ¾ of cell diameter • 4+ thin rim of hemoglobin • Polychromasia • Describes the blue-gray color of immature RBC’s which have left the bone marrow prematurely. • These RBC’s are larger than normal. • .he blue-gray color is due to residual RNA. When stained with a supravital stain such as methylene blue, they are called reticulocytes

5. Shape variations • Target cell (codocyte) • RBC’s have a centrally stained area and resemble a shooting target. • Caused by excess membrane cholesterol or decreased hemoglobin content. • Seen in liver disease, hemoglobinopathies, iron deficiency anemia, post-splenectomy. Can also be artifactual. • Spherocyte • Appear as small red cells with no central pallor; they have the lowest surface area-volume ratio; shape change is irreversible. • Caused by loss of membrane due to aging, antibody coating or genetic defect • Seen in autoimmune hemolytic anemia, transfusion reaction, hereditary spherocytic anemia.

6. Ovalocyte/Elliptocyte • Oval or cigar shaped red cells. May be normochromic or hypochromic, normocytic or macrocytic. • Exact mechanism for deformity is not well defined. • Ovalocytes seen in myelodysplastic syndrome, thalassemia, pernicious anemia, B12 or folate deficiency. • Elliptocyes seen in iron deficiency anemia, hereditary elliptocytosis, idiopathic myelofibrosis. • Stomatocyte • Normal size red cell with “slitlike” area of central pallor resembling a mouth. • Exact mechanism for abnormality not well defined. Usually artifactual • Seen in hereditary spherocytosis, hereditary stomatocytosis, acute alcoholism, Rh null phenotype.

7. Sickle Cell (drepanocyte) • Red cell is in the shape of a sickle or crescent. • Caused by hemoglobin S polymerization into rigid inflexible cells with at least one pointed projection. Polymerization occurs in lowered oxygen level or decreased pH. • Seen in hereditary condition called sickle cell disease. Can be homozygous or heterozygous. Also seen in hereditary Hemoglobin C disease or combination of both. • Acanthocyte • Red cell of normal or slightly small size with 3-8 thorny, spine-like projections that are irregularly spaced around the cell. The projections may vary in length. • Exact mechanism is unknown, but it is known that they have excess cholesterol and increased surface membrane. • Seen in congenital abetalipoproteinemia, alcohol intoxication, severe hepatic disease and post-splenectomy

8. Fragmented red cells (Schistocytes, Burr cells, Helmet cells) • Schistocytes • Red cells appear as fragment of irregular size and shape. • Caused by loss of membrane by mechanical means. • Seen in patient with prosthetic heart valves, clostridial infections, microangiopathic hemolytic anemia, hemolytic uremic syndrome (HUS), thrombotic thrombocytopenia purpura (TTP), disseminated intravascular coagulation (DIC) • Helmet cells(also called bite cells) • Red cells resemble an army helmet with short straps. • Caused by splenic pitting. • Seen in G6PD deficiency, pulmonary emboli and DIC.

9. Burr cells (echinocytes) • Red cells have regular sharp projections around the membrane. • Caused by various factors such as dehydration or a change in the tonicity of the intravascular fluid. Also can be artifactual. • Seen in renal disease, liver disease and burn patients

10. Variations in red cell distribution • Agglutination • Red cells clump together when cooled to room temperature. Saline will not disperse the clumps, but warming usually will. • Caused by red cell antibodies • Seen in cold antibody syndromes, paroxysmal cold hemoglobinuria. • Rouleaux • Red cells are arranged in groups resembling stacks of coins. Saline will disperse the formations. • Caused by elevated globulins or fibrinogen in the plasma. • Seen in multiple myeloma and Waldenstroms’s macroglobulinemia

11. Red cell inclusions • Howell-Jolly bodies • Single round, solid-staining purple dot composed of DNA located on the periphery of the RBC. • Caused by accelerated or ineffective erythropoiesis in which chromosome fragments are left in the cytoplasm. • Seen following splenectomy and in thalassemias, hemolytic anemias and megaloblastic anemia. • Basophilic stippling • Tiny, round, solid-staining blue granules composed of RNA. Can be diffuse, coarse or punctate • Usually artifactual caused by precipitation of RNA during staining of the smear. • Seen defective or accelerated heme synthesis, lead poisoning and thalassemias.

12. Pappenheimer bodies (Siderotic granules in Prussian blue stain) • Purplish irregular aggregates of granules composed of ferric(Fe3) iron. • Caused by excess available iron throughout the body. • Seen in sideroblastic anemia, alcoholism, thalassemia, asplenism. • Heinz Bodies • May not be seen on Wright’s stain. When stained with a supravital stain such as crystal violet or brillian cresyl blue, they appear as large blue inclusions that are rigid and distort the cell membrane. • Cause by denatured or precipitated hemoglobin. • Seen in alpha thalassemia, G6PD deficiency and unstable hemoglobin syndromes.

13. Cabot ring • Purplish ring-shaped, figure-eight, or loop-shaped structures composed of nuclear membrane remnants. Rarely seen. • Exact mechanism unkown • Seen in pernicious anemia, lead poisoning, homozygous thalassemia and post-splenectomy.