Hematology Part 2: Anemia Overview

Hematology Part 2

• Topic covered in this part of the course is hematology.
• The presenter is Dorothy Maka, DNP, APN, FNP-BC, from DePaul University, NSG 422.

Section 1.0 - Alterations in Erythrocytes, Overview of Anemia, and Red Blood Cell Measures

• Erythrocytes are altered in anemia.
• Anemia is defined as a reduction in the total number of erythrocytes (RBCs) in the circulating blood or in the quality or quantity of hemoglobin.
• Many various causes of anemia exist.

Anemia

• Anemia is classified by size and hemoglobin.
• Size classifications include macrocytic, microcytic, and normocytic.
• Hemoglobin content classifications include normochromic and hypochromic.
• Classic symptoms include fatigue, weakness, dyspnea, and pallor.
• Reduced oxygen-carrying capacity leads to hypoxia.

Red Blood Cell Measures for Anemia

• Hemoglobin (HB): Amount of hemoglobin in the blood (12-17.4 g/dL)
• Hematocrit (HCT): Proportion of red blood cells to total blood cells (36-52%)
• Mean corpuscular hemoglobin (MCH): Average mass of hemoglobin per red blood cell (27-34 pg).
• Mean corpuscular hemoglobin concentration (MCHC): Concentration of hemoglobin in select volume of packed RBCs (32-36 g/dL)
• Mean corpuscular volume (MCV): Average red blood cell size (80-100 fL)
• Red blood cell count (RBC): Number of RBCs (4.2-6.1 million cells/mcL)
• Red blood cell distribution width (RDW): Range of RBC sizes (11.5-14.5).

Section 2.0 - Macrocytic Anemias

• Types include Vitamin B12 deficiency, pernicious anemia, and folate acid deficiency.
• Macrocytic anemia is characterized by large red blood cells.
• The cause is defective DNA synthesis, while RNA synthesis occurs normally.
• Causes are due to deficiencies in vitamin B12 or folate.
• Subtypes include vitamin B12 deficiency and folate deficiency.
• Causes of B12 deficiency include gastric abnormalities, pernicious anemia, gastric resection/bariatric surgery, strict vegetarianism, and small bowel disease.
• Clinical manifestations of Vitamin B12 deficiency anemia include vague initial symptoms (weakness, fatigue), a sore tongue that appears beefy red, neurological symptoms (difficulty walking, paresthesia of feet and fingers), and nerve demyelination.
• Evaluation involves complete blood count to observe increased MCV and decreased HCT, decreased serum vitamin B12, and assessment of antibodies.
• Treatment includes parenteral or high oral doses of vitamin B12. Treatment depends on the cause.

Macrocytic Anemia - Folate Deficiency

• Folate deficiency causes macrocytic anemia.
• Causes include absorptive etiologies (chronic malnutrition) and dietary deficiency.
• Sources of folate include meats, enriched breads/cereals, fortified grain products, leafy green vegetables, and citrus fruits.
• Clinical manifestations may include general anemia symptoms, cheilosis, stomatitis, or oral mucosal ulcerations
• Evaluation involves increased MCV and decreased folate levels.
• Treatment includes oral folate supplementation and increasing folate-rich foods.

Section 3.0 - Microcytic-Hypochromic Anemias - Iron-Deficiency Anemia

• Microcytic-hypochromic anemias include iron deficiency.

• Iron deficiency anemia is the most common type of anemia globally.

• Deficiencies include inadequate dietary intake, blood loss, chronic blood loss (e.g. GI bleed, ulcers), use of medications (e.g. aspirin, NSAIDS), and menorrhagia.

• Clinical manifestations include symptoms that appear when hemoglobin drops to 7-8 g/dl, such as fatigue, weakness, shortness of breath, and pallor. Additional symptoms include brittle, thin, and spoon-shaped nails, stomatitis, and painful ulcerations in the mouth.

• Evaluation involves complete blood count showing decreased MCV, decreased MCH/MCHC, and decreased HCT, and serum ferritin.

• Treatment includes identifying and eliminating blood loss sources, iron replacement therapy (e.g., oral ferrous sulfate, parenteral iron dextran), and a duration of therapy generally lasting 6-12 months.

Section 4.0 - Normocytic-Normochromic Anemia

• Types include aplastic, post-hemorrhagic, hemolytic, and anemia of chronic disease.
• Aplastic anemia causes reduction in all types of blood cells due to autoimmune diseases or chemical exposures (e.g., cancer chemotherapy). Clinical manifestations include anemia, fatigue, pallor, dyspnea, neutropenia, fever, thrombocytopenia, and symptoms of bleeding. Treatment depends on the cause.
• Post-hemorrhagic anemia results from acute blood loss from the vascular space. Clinical manifestations and treatment depend on the severity of the blood loss. Treatment will involve intravenous administration of saline, dextran, albumin, or plasma for volume replacement, and fresh whole blood in cases of large volume losses.
• Hemolytic anemia includes transfusion related hemolysis and sickle cell anemia. Sickle cell anemia is an autosomal recessive disorder with a genetic mutation resulting in structural changes in hemoglobin (hemoglobin S). The disease process involves vaso-occlusion leading to tissue ischemia and infarction. Clinical manifestations include jaundice, vaso-occlusive pain crisis, and tissue infarct complications. Treatments include medications (e.g., hydroxyurea), blood transfusions, hydration, and oxygen.
• Anemia of chronic disease is associated with mild-to-moderate anemia from decreased erythropoiesis resulting from chronic inflammation or chronic systemic disease such as chronic kidney disease. Causes include decreased erythrocyte lifespan, suppressed bone marrow response, and altered iron metabolism in macrophages. Kidney damage affects erythropoietin production in the anemia of chronic disease.

Section 5.0 - Polycythemia

• Polycythemia is an overproduction of red blood cells. This can be relative or primary.
• Relative polycythemia is caused by blood hemoconcentration due to dehydration.
• Primary polycythemia (polycythemia vera) is a blood cancer in which the bone marrow produces too many red blood cells.
• Manifestations include splenomegaly, abdominal pain, and a hypercoagulable state.
• Treatment includes phlebotomy and medications.

Application Exercise

• A patient, Mrs. Joan Cass, presented with fatigue, pallor, dyspnea, and palpitations.
• Her lab results indicated low hematocrit, hemoglobin, reticulocyte count, high MCV, and normal MCH and MCHC.. This suggested pernicious anemia.
• The nurse practitioner should ask about neurologic symptoms such as paresthesia due to the potential for nerve damage.
• Intramuscular injection rather than oral administration of vitamin B12 is used due to poor intestinal absorption in pernicious anemia.