Approach to anemia

This is an overview of approach to anemia

1. Approach to patient with Anemia Oct 17. ,2017 Dep’t of Internal Medicine Melaku Yitbarek(M.D.)

2. Outline: Definition Causes of Anemia Evaluation of a patient with anemia Hx PE Lab Evaluation Approach to Anemia

3. a decrease in red blood cell (RBC) mass that can be detected by hemoglobin (Hb) concentration, hematocrit (Hct), and RBC count ƒor adult males: Hb <13g/dl or Hct <0.41 ƒor adult females: Hb <12g/dl or Hct <0.36 Definition

4. There are two general approaches one can use to help identify the cause of anemia: A kinetic approach , addressing the mechanism(s) responsible for the fall in hemoglobin concentration A morphologic approach categorizing anemias via alterations in RBC size (ie, mean corpuscular volume) and the reticulocyte response Causes of Anemia

5.  Anemia can be caused by one or more of three independent mechanisms: decreased RBC production, increased RBC destruction, and blood loss Kinetic approach  

6. Anemia will ultimately result if the rate of RBC production is less than that of RBC destruction. The more common causes for reduced (effective) RBC production include: Lack of nutrients, such as iron, B12, or folate. Bone marrow disorders (eg, aplastic anemia, pure RBC aplasia, tumor infiltration) Bone marrow suppression (eg, drugs, chemotherapy, irradiation). Low levels of trophic hormones which stimulate RBC production, such as EPO (eg, chronic renal failure), thyroid hormone (eg, hypothyroidism), and androgens (eg, hypogonadism). The anemia of chronic disease/inflammation, associated with infectious, inflammatory, or malignant disorders, is characterized by reduced availability of iron due to decreased absorption from the gastrointestinal tract and decreased release from macrophages, Decreased RBC Production

7. A RBC life span below 100 days is the operational definition of hemolysis Hemolytic anemia will ensue when the bone marrow is unable to keep up with the need to replace more than about 5 percent of the RBC mass per day Inherited hemolytic anemias (eg, hereditary spherocytosis, sickle cell disease, thalassemia major) Acquired hemolytic anemias (autoimmune hemolytic anemia, thrombotic thrombocytopenic purpura,hemolytic uremic syndrome, malaria) Increased RBC Destruction

8. Blood loss is the most common cause of anemia and may take any one of a number of forms: Obvious bleeding (eg, trauma, melena, hematemesis, menometrorrhagia) Occult bleeding (eg, slowly bleeding ulcer or carcinoma). Induced bleeding (eg, repeated diagnostic testing ,, excessive blood donation) Blood Loss

9. The causes of anemia can also be classified according to measurement of RBC size The normal RBC has a volume of 80 to 96 femtoliters (fL) and a diameter of approximately 7 to 8 microns, equal to that of the nucleus of a small lymphocyte. Thus, RBCs larger than the nucleus of a small lymphocyte on a peripheral smear are considered large or macrocytic, while those that appear smaller are considered small or microcytic Based on Size RBCs are Classified as microcytic,macrocytic and normocytic Morphologic approach

10. Macrocytic Anemia: Macrocytic anemias are characterized by an MCV above 100 fL An increased MCV is a normal characteristic of reticulocytes Any condition causing marked reticulocytosis will be associated with an increased MCV. Abnormal nucleic acid metabolism of erythroid precursors (eg, folate or cobalamin deficiency and drugs interfering with nucleic acid synthesis, such as zidovudine and hydroxyurea ). Other common causes include alcohol abuse, liver disease, and hypothyroidism. Morphological…

11. Microcytic Anemia: Microcytic anemias are characterized by the presence of "small" RBCs (ie, MCV below 80 fL). Microcytosis is usually accompanied by a decreased hemoglobin content within the RBC, with parallel reductions in MCV and MCH, producing a hypochromic (low MCH ) as well as a microcytic (low MCV ) appearance on the blood smear Morphological…

12. Microcytic Anemia Cont’d The following pathologic processes lead to the production of hypochromic microcytic red cells: Reduced iron availability — severe iron deficiency, the anemia of chronic disease, copper deficiency Reduced heme synthesis — lead poisoning, congenital or acquired sideroblastic anemia Reduced globin production — thalassemic states, other hemoglobinopathies Rare disorders due to defects in iron absorption, transport, utilization, and recycling Morphological…

13. Normocytic Anemia : Normal mean corpuscular volume ( normocytic anemia: MCV 80 to 100 fL) Acute blood loss Iron deficiency anemia (early) Anemia of inflammation/anemia of chronic disease (eg, infection, inflammation, malignancy) Chronic renal insufficiency Endocrine dysfunction Hypothyroidism Hypopituitarism Morphological…

14. Initial Approach: Is the patient bleeding (now or in the past)? Is there evidence for increased RBC destruction (hemolysis)? Is the bone marrow suppressed? Is the patient iron deficient? If so, why? Is the patient deficient in folic acid or vitamin B12? If so, why? Evaluation of a Patient

15. Hx: Is there a history of, or symptoms related to, a medical condition which is known to result in anemia (eg, tarry stools in a patient with ulcer-type pain, rheumatoid arthritis, renal failure)? Is the anemia of recent origin, subacute, or lifelong? The use of medications, both prescribed as well as over-the-counter, should be examined Evaluation…

16. PE: the presence or absence of tachycardia, dyspnea, fever, or postural hypotension should be noted. evaluation for jaundice and pallor is a standard part of the physical examination Evaluation…

17. Conjunctival Pallor

18. Initial testing of the anemic patient should include a CBC RBC indices Peripheral blood smear Reticulocyte count Laboratory Evaluation

19. Thank You…