MLAB 1315- Hematology Keri Brophy-Martinez Unit 8: Morphological Changes Associated with Disease

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)

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

Stain variations Hypochromia (correlate with MCHC) Polychromasia 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

Shape variations Target cell (codocyte) Spherocyte 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.

Exact mechanism for abnormality not well defined. Usually artifactual 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.

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

Fragmented red cells (Schistocytes, Burr cells, Helmet cells) 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.

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

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

Red cell inclusions Basophilic stippling 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.

Cause by denatured or precipitated hemoglobin. 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.

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.