Introduction to anemia

1. Introduction to anemia Gülay ÇİLER ERDAĞ,MD

2. Hematopoiesis • Begins in the embryo during the third week of gestation • Developmental hematopoiesis occurs in three stages • Mesoblastic • In the yolk sac first produces erythrocytes and leukocytes • Hepatic • By the 12th week of gestation liver and the spleen are the predominant sites • Myeloid • By the 30 weeks gestation, the bone marrow assumes its ultimate role as the major site of production of the formed elements of the blood

5. The predominant cellular element in the blood is eryhtrocyte: RBC (red blood cell) • Under the stimulus of erhythropoietin and other humoral factors • erythroid burst forming units (from the pluripotent stem cells) and colony forming units give rise to identifiable erythroblasts • Begin to synthesize Hb • Nucleated RBC • Nucleus extruded Young erythrocyte

8. Hb • Binds to oxygen in the lungs and transports it to the tissues • Tetramer consisting of two pairs of unlike polypeptide chains each attached to a HEME ( molecule of protoporphyrin ferrous iron) • The primary Hb • in the postnatal life is HbA (2α2β) • Initial months of gestation HbF (2α2γ)

11. At the time of birth γ and β chain synthesis is approximately equal and 60%-80% of the total Hb is HbF • γ glb synthesis almost ceases during the initial months of life • By 6 months of age the percentage of HbF approximates that of adults(<2%) • HbF is resistant to both alkali and dilute acid. It binds less avidly than does HbA to 2,3 diphosphoglycerate • an organic phosphate in the erythrocyte important in modulating oxygen uptake and release by Hb • The affinity of HbF for oxygen is high

13. Because of intrauterine hypoxia and the high affinity of HbF for oxygen(resulting in a shift to the left of oxygen-Hb dissociation curve) • Erythropoietin secretion is enhanced during fetal life • During the final months of gestation and at birth values for Hb and Hct are higher than those for older children

14. Hemoglobin F (Hb F), composed of 2 alpha and 2 gamma globin chains, is the normal hemoglobin of the fetus and newborn. Normally in the second trimester, gamma chain production (and Hgb F levels) decrease and beta chain production increases, resulting in increasing levels of hemoglobin A (Hb A), the major normal adult hemoglobin (2 alpha and 2 beta globin chains). Hemoglobin A2 (Hb A2) (2 alpha and 2 delta globin chains) also comprises a small amount (<3.3%) of hemoglobin normally found in adults. Hb A2 values at birth are <1%. • Reference Values • HEMOGLOBIN A2 • 1-30 days: 0.0-2.1% • 1-2 months: 0.0-2.6% • 3-5 months: 1.3-3.1% • > or =6 months: 2.0-3.3% • HEMOGLOBIN F • 1-30 days: 22.8-92.0% • 1-2 months: 7.6-89.8% • 3-5 months: 1.6-42.2% • 6-8 months: 0.0-16.7% • 9-12 months: 0.0-10.5% • 13-17 months: 0.0-7.9% • 18-23 months: 0.0-6.3% • > or =24 months: 0.0-0.9%

15. Newborns less than one week old have hemoglobin of 14-22 g/dl. • By six months of age, hemoglobin runs between 11 and 14 g/dl. • Between 1 year and 15 years of age hemoglobin runs between 11-15 g/dl. • Normal adult hemoglobin depends on gender: • ♀ 12-16 g/dl • ♂ 14-18 g/dl • In geriatric age group, men and women have same hemoglobin range:  12-16 g/dl.

16. Anemia • A reduction in RBC volume or Hb concentration below the range of values occurring in healthy person • Although a reduction in the amount of circulating Hb decreases the oxygen carrying capacity of the blood few clinical disturbances occur until Hb levels fall below 7-8gr/dl • Below this level pallor becomes evident in the skin and mucous membranes

17. Physiologic adjustments to anemia • Increasedcardiacoutput • Increasedoxygenextraction • Shunting of bloodflowtowardvitalorgansandtissues • Inadditiontheconcentration of 2,3 DPG increases • Shifttotheright of oxygendissociationcurve, reducingtheaffinity of Hbforoxygen • results in morecomplete transfer of oxygentothetissues

18. Anemia can be defined as a reduction in the hemoglobin, hematocrit or red cell number • The pathophysiologic effects of anemia depend upon the rate at which the anemia progresses

19. In an acute hemorhage • the arterial pressure falls, cardiac output decreases, peripheral vasculature collapses and the patient rapidly enters hypovolemic shock • The sudden rapid loss of 30% of the total blood volume often results in death unless there is immediate medical intervention

20. In a slowly developing anemia • cardiac output increases, blood shunted from nonvital organs and hemoglobin oxygen affinity decreases due to increased levels of 2,3 DPG. • Total blood volume remains remarkably constant. More than 50% of the red cell mass can be lost slowly with minimal effects

21. It must be remembered that anemia is not a disease rather it’s a sign of disease • The clinical effects (lack of oxygen) include • Tiredness, lassitude, weakness, pallor • Dyspnea and anginal pain are not uncommon after exercise • Jaundice may occur in some anemias

22. Classification of Anemias • Have a variety of ways - depending on criteria used: • Functional • Morphological • Clinical • Quantitative

23. Functional Classification of Anemias • Decreased RBC production (hypoproliferative) • Defective hemoglobin synthesis • Fe deficiency • B12 deficiency • Folate deficiency • Impaired bone marrow or stem cell function, as in leukemia • Increased RBC destruction, as in sickle cell anemia or hemolytic anemia • Combination of the two (sometimes called “ineffective erythropoiesis”)

24. Morphological Classification of Anemias • Morphological based on sizes and color of RBCs • NormochromicNormocytic • HypochromicMicrocytic • NormochromicMicrocytic • NormochromicMacrocytic

25. Clinical Classification of Anemias • According to their associated causes: • Blood loss • Iron deficiency • Hemolysis • Infection • Nutritional deficiency • Metastatic bone marrow replacement

26. QuantitativeClassification of Anemias • Quantitatively by: • Hematocrit • Hemoglobin • Blood cell indices • Reticulocyte count

27. Hemoglobin and Hematocrit 1 of 2 • Anemia usually diagnosed on either hemoglobin or hematocrit values. • Remember, normal ranges vary depending on age, gender, state of hydration, patient positioning and local patient population.

28. Hemoglobin and Hematocrit 2 of 2 • On basis of H&H, anemia can be classified as mild, moderate, or severe. • On basis of duration of onset, anemia can be classified as either chronic or acute. • Rules of Three: • RBC X 3 = Hemoglobin • Hemoglobin X 3 = Hematocrit • Ratio of Hb and Hct will vary with cause of anemia and affect the RBC indices, particularly the MCV (Mean Corpuscular Volume). • Microscopic examination of peripheral blood smear is required for evaluation of anemia.  Bone marrow aspirates and smear evaluation may also be needed.

29. RBC Indices • RBC indices include: • Mean Corpuscular Volume (MCV) • Mean Corpuscular Hemoglobin (MCH) • Mean Corpuscular Hemoglobin Concentration (MCHC) • RBC Distribution Width (RDW)

30. MCV • Mean cell volume • MCV is average size of RBC • MCV = Hct x 10 RBC (millions) • If 80-100 fL, normal range, RBCs considered normocytic • If < 80 fL are microcytic • If > 100 fL are macrocytic • Not reliable when have marked anisocytosis

31. MCH • MCH is average weight of hemoglobin per RBC. • MCH = Hgb x 10 RBC (millions)

32. MCHC • MCHC is average hemoglobin concentration per RBC • MCHC = Hgb x 100 Hct (%) • If MCHC is normal, cell described as normochromic • If MCHC is less than normal, cell described as hypochromic • There are no hyperchromic RBCs

33. RDW • Most automated instruments now provide an RBC Distribution Width(RDW) • An index of RBC size variation • May be used to quantitate the amount of anisocytosis on peripheral blood smear • Normal range is 11.5% to 14.5% for both men and women

34. RBC Indices and Other Tests • RBC indices are automatically calculated by instruments. • Microscopic evaluation will determine if RBCs are normocytic, microcytic, or macrocytic and normochromic or hypochromic. • Use of RBC indices in differential diagnosis can provide picture of what is occurring clinically. • If anemia caused be bone marrow failure, requires information about RBC production. Information obtained from reticulocyte count. Reticulocyte count measures effective RBC production. • As study different anemias, will learn morphology.

35. Treatment of Anemias • Treated according to cause; Should know cause before beginning treatment. • Patient can have more than one cause of anemia. • Must use diagnostic tests to determine cause(s). • Do diagnostic tests before transfusions, because transfusions obscure and confuse findings.

36. Hgb (In the Diagnosis of Anemia) • Hbg is the main component of RBCs and carries oxygen to tissues. • Three methods to measure hemoglobin: • Cyanmethemoglobin (recommended method) • Oxyhemoglobin • Iron Content 

37. Hct (In the Diagnosis of Anemia) 1 of 3 • Is packed RBC volume • Is ratio of RBC volume to volume of whole blood • Usually expressed in percentage (42%) or as decimal fraction (.42) • Venous and arterial hematocrits closely agree • Specimen of choice is EDTA (ethylenediaminetetra acetic acid), oxalate or heparin

38. Hct (In the Diagnosis of Anemia) 2 of 3 • Measurement done by centrifugation or through calculations performed on many automated measurements. • Calculated hematocrit is product of MCV and RBC count. • Normal ranges are 42-52% in men and 37-47% in women. • Normal ranges also vary among age groups, institutions, and geographic locations.

39. RBC Indices (In the Diagnosis of Anemia) 1 of 2 • RBC indices are readily available from the automated hematology counting devices • MCV is measured directly or calculated from hematocrit and RBC count; MCH and MCHC are both calculated

40. RBC Indices (In the Diagnosis of Anemia) 2 of 2 • In various anemic states, indices may be altered: • Microcytic Anemia: • MCV usually 50-80 fL • MCH usually 15-25 pg • MCHC usually 22-30% • Macrocytic Anemia: • MCV usually 100-120 fL

41. Peripheral Blood Smear (In the Diagnosis of Anemia) • Very useful in diagnosing and classifying anemias • Look for: • Neutropenia • Thrombocytopenia • Hypochromia • Size and shape of RBCs • Unusual leukocytes (hypersegmentation) • Red cell inclusions: basophilic stippling, Howell-Jolly bodies…

42. Reticulocyte Count (In the Diagnosis of Anemia) • Useful in determining response and potential of bone marrow. • Reticulocytes are non-nucleated RBCs that still contain RNA. • Visualized by staining with supravital dyes, including new methylene blue or brilliant cresyl blue; RNA is precipitated as dye-protein complex. • Normal range is 0.5-2.0% of all erythrocytes. • If bone marrow responding to anemia, should see increases in retic count. • Newborns have higher retic count than adults until second or third week of life.

43. Bone Marrow (In the Diagnosis of Anemia) • Bone marrow aspiration and biopsy are important diagnostic tools in the determination of anemia.

44. Other Tests (In the Diagnosis of Anemia) • Hemoglobin Electrophoresis • Antiglobulin Testing • Osmotic Fragility • Sugar Water Test • Ham’s Test • RBC Enzymes • B12, Fe, TIBC, Folate Levels

45. Anemia is usually classified according to • Etiology • Pathophysiology • Morphology

46. Laboratory diagnosis • Initial investigation and tentative diagnosis is made with a relatively small number of tests • The precise diagnosis is made with further special tests • Screening is usually done with CBC (complete blood count) • The exact procedures in a CBC depends upon the instrumentation in the laboratory

47. Most laboratories now use automated multiparameter instruments. These are • Hb(hemoglobin) • RBC • MCV • Htc(hematocrit) • MCH • MCHC • RDW • WBC • Platelet and MPV Directly measured values Calculated values

48. Htc X10 • MCV: • MCH: • MCHC: (90±7 fl) RBC Hb X100 (30±3) RBC Hb X100 (33±2) Htc

49. spherocytosis eliptocytosis stomatocytosis poikilocytosis acanthocytosis Fragmentation hemolysis

50. Sickle cell anemia; target cells and sickled cells Normal RBC Target cells Heinz body anemia Thalassemia; severe hypochromia Anisopoikilocytosis, target cells