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Overview of Hematology

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1 Overview of Hematology
Dr. Gamal Badr PhD in Immunology (Paris Sud University, France) Associate Professor of Immunology Assiut University, Egypt Tel: Fax: s: or Websites:

2 Hematology Hematology, also spelled haematology, is the branch of internal medicine, physiology, pathology, clinical laboratory work, and pediatrics that is concerned with the study of blood, the blood-forming organs, and blood diseases. Hematology includes the study of etiology, diagnosis, treatment, and prevention of blood diseases.

3 Topics Hematopoiesis Transfusion Complete blood count (CBC) Anemia
Polycythemia Leukopenia Leukemia and lymphoma Myeloma Coagulation

Transportation Oxygen Nutrients Hormones Waste Products Regulation Fluid, electrolyte Acid-Base balance Body temperature Protection Coagulation Fight Infections

5 Components of Blood Blood components are:
Suspension of cells in a solute of water, proteins, and electrolytes Average volume is 5 liters 70mL per kg body weight Blood components are: A. Liquid component -Plasma (55%) Plasma is a yellow colored solution containing a mixture of water, amino acids, proteins, clotting factors, carbohydrates, lipids, vitamins, hormones, electrolytes, and cellular wastes.

6 B. Cellular component (45%)
Thrombocytes/Platelets Leukocytes/ white blood cells (WBCs) Erythrocytes/ red blood cells (RBCs)

7 Complete Blood Count (CBC)
White blood cells (WBCs) Normal 4, ,000 /µℓ Differential cells: Neutrophils, lymphocytes, monocytes, eosinophils, basophils, Dendritic cells. Red blood cells (RBCs) ♂ 4.5 – 5.5 x 106/µℓ ♀ 4.0 – 5.0 x 106/µℓ Hemoglobin (Hgb), Hematocrit (Hct) The hematocrit is the percent of whole blood that is composed of red blood cells. The hematocrit is a measure of both the number of RBCs and the size of red blood cells. Mean corpuscular volume (MCV) is a measure of the average volume of a red blood corpuscle Platelets (PLT) Normal 15, ,000 /µℓ

8 Hematopoiesis Development of all blood cells and other formed elements
Sites vary throughout development Before birth: liver, spleen Adult: bone marrow (BM) of axial skeleton. Stem cells Primitive; self-replicate and differentiate to become increasingly specialized progenitor cells which form mature cells Process regulated by growth factors (interleukins, erythropoietin, thrombopoietin, G-CSF) Early lineage division between progenitors for lymphoid and myeloid cells

9 Hematopoiesis

10 Thrombocytes/Platelets
Must be present for clotting to occur Involved in hemostasis

11 Leukocytes/White Blood Cells (WBCs)
Granulocytes Contain granules in their cytoplasm Basophils Eosinophils Neutrophils Agranulocytes Contain no granules in their cytoplasm Monocytes Lymphocytes

12 Types and Functions of Leukocytes
CELL FUNCTION Granulocytes Neutrophil Eosinophil Basophil Phagocytosis: early phase of inflammation Phagocytosis: parasitic infections Inflammatory response, allergic response Agranulocytes Lymphocyte Monocyte Cellular and humoral immune response Phagocytosis: cellular immune response

13 Erythrocytes/Red Blood Cells (RBCs)
Immature RBC (circle and nucleated), while mature RBC is circle and non nucleated Composed of hemoglobin (Hb or Hgb) Erythropoiesis is the production of RBCs Stimulated by hypoxia (decrease of O2 in the blood) Controlled by erythropoietin (hormone synthesized in kidney) Hemolysis is the destruction of RBCs Releases bilirubin into blood stream Normal lifespan of RBC = 120 days

14 Structures of the Hematologic System
Bone Marrow a primary lymphoid organ (Hematopoiesis) Soft connective tissue in core of bones The production of all types of blood cells (Hematopoiesis) generated by a remarkable self-regulated system that is responsive to the demands put upon it. Liver Receives 24% of the cardiac output (1500 ml of blood each minute) Liver has many functions. The hematologic functions: Liver synthesis plasma proteins including clotting factors and albumin Liver clears damaged and non-functioning RBCs/erythrocytes from circulation Spleen a secondary lymphoid organ exerts many functions: Hematopoietic function: Produces fetal RBCs Filter function: Filter and reuse certain cells Immune function: Lymphocytes, monocytes Storage function: 30% platelets stored in spleen

15 RBCs (erythrocytes) Mature RBCs are biconcave disks that contain oxygen-carrying hemoglobin, discard their nuclei during development and so cannot reproduce or produce proteins. In the embryo and fetus, RBCs production occurs in the liver and spleen; but after birth, it occurs in the bone marrow. Normal lifespan = 120 days Reticulocytes (Immature red blood cells) Calculating proportion within circulation assists in determining cause of anemia Normal % is 1-2% Low % (< 0.4%) suggests decreased production (i.e. nutritional or marrow problem) High % (< 3%) suggests bleeding or premature destruction of red blood cells (i.e. hemolysis)

16 Red Blood Cells Blood RBCs Bone marrow 1 – 2%

17 RBC Production and Its Control
The total number of red blood cells remains relatively constant due to a negative feedback mechanism utilizing he hormone erythropoietin, which is released from the kidneys and liver in response to the detection of low oxygen levels.

18 Factors Affecting RBCs Production
Dietary Vitamins B12 and folic acid are needed for DNA synthesis, so they are necessary for the reproduction of all body cells, especially in hematopoietic tissue. Dietary Iron is needed for hemoglobin synthesis. Destruction of RBCs with age, RBCs become increasingly fragile and are damaged by passing through narrow capillaries. Macrophages in the liver and spleen phagocytize damaged red blood cells. Hemoglobin from the decomposed RBC is converted into heme and globin. Heme is decomposed into iron which is stored or recycled and biliverdin and bilirubin which are excreted in bile.

19 Hematological Disorders
RBCs Disorders &Others Anemias Benign & Malignant WBCs Disorders Hemostatic Disorders 1ry & 2ry Transfusion Medicine


21 RBCs Disorders Anemia Almost 1/3 of the world population is anemic!
Anemia is defined as a reduction in one or more of the major RBC measurements: Hgb, Hct, or RBC count Normal Hgb concentration– 15 in males ; 14 in females Patients are “anemic” when Hgb is < 12 g/dL Determining reticulocyte count and MCV are first steps in determining etiology MCV  = 10 x HCT(percent) ÷ RBC numbers (millions/µL) Almost 1/3 of the world population is anemic! Increase in hgb that occurs in men is mostly related to effect of androgens on release of erythropoietin ; gender disparity becomes less significant in advanced age

22 RBCs Disorders - Anemia
Manifestations related to duration and severity of anemia: May provide important clues as to etiology Body has physiologic responses to chronic anemia such that many patients are asymptomatic until Hgb < 8 g/dL Fatigue, pallor, dyspnea, dizziness, ischemic pain, cognitive abnormalities Two main approaches that are not mutually exclusive: Morphological approach. Biologic or kinetic approach.

23 Anemia - (Morphological approach)
By calculation from an independently-measured RBCs count and hematocrit: MCV  (femtoliters) = 10 x HCT(percent) ÷ RBC (millions/µL) The normal MCV ( fL) Microcytosis – small cells (MCV <80) – microcytic anemia Macrocytosis – large cells (MCV >100) – macrocytic anemia Normocytic anemia is defined as an anemia with a MCV of which is the normal range, but the HCT and Hbg is decreased

24 Microcytic Anemia (MCV <76 fL)
The normal MCV ( fL) Microcytosis – small cells (MCV <80) Most common type of anemia encountered in primary care Differential diagnosis Hemoglobinopathy (inherited) Iron deficiency Chronic disease (may also be normocytic) Inflammation Lead poisoning

25 Microcytic Anemia Peripheral blood smear
Microcytosis, Hypochromic (are paler than usual)

26 Macrocytic Anemia Macrocytosis – large cells (MCV >100)
Differential diagnosis B12 deficiency Pernicious anemia: (Biermer's anemia, Addison's anemia) is caused by loss of gastric parietal cells, which are responsible for the secretion of factors that are responsible for absorption of vitamin B12 in the ileum. Folate deficiency Check vitamin B12, RBC folate, fasting homocysteine (HC), and methylmalonic acid (MMA) HC and MMA are elevated in subclinical B12 and folate deficiency Medications associated with elevated MCV include…

27 Anemia - (kinetic approach)
Abnormality? Production of RBCs (hypoproliferation) Survival/Destruction of RBCs The key test is the reticulocyte count Mechanisms of Anemia Decreased erythrocyte production Erythrocyte loss Decreased erythropoietin production Hemorrhage Inadequate marrow response to erythropoietin Hemolysis

28 Anemia - (kinetic approach)
Mechanisms Short survival/Destruction of RBCs/ loss of RBCs Blood loss / hemorrhage Accidents Ulcer or surgery in Gastrointestinal tract (GI), menstruation Hemolysis Shortened RBC survival time. Decreased production (hypoproliferative) Nutritional deficiency (iron, B12, and folate) Systemic illness (chronic kidney disease (CKD), cancer, rheumatologic disease, etc.) Bone marrow disorders

29 RBCs Disorders - Anemia
Marrow production Thalassemias Myelodysplasia Myelophthisic Aplastic anemia Nutritional deficiencies Red cell destruction (hemolytic) Hemoglobinopathies Enzymopathies Membrane disorders Autoimmune

30 RBCs Disorders - Red cell destruction
Causes: Elevated reticulocyte count Mechanical Autoimmune Drug Congenital

31 Red cell destruction -Hemolytic Anemia
History and physical findings Hemolytic anemias are either acquired or congenital. The laboratory signs of hemolytic anemias include: Increased LDH (Lactate dehydrogenase). Increased bilirubin. Increased reticulocyte count. Decreased haptoglobin. Urine hemosiderin Jaundice is common Occasional pain in the left upper abdominal region. (splenomegaly)

32 Red cell destruction -Hemolytic Anemia
Congenital Membrane defects Hereditary spherocytosis : auto-hemolytic anemia characterized by the production (RBCs) that are sphere-shaped, rather than bi-concave disk shaped Hereditary elliptocytosis: also known as ovalocytosis, is an inherited blood disorder in which an abnormally large number of the patient's RBCs are elliptical rather than the typical biconcave disc shape. Enzyme defects Glucose-6-phosphate dehydrogenase (G6PD) deficiency: X-linked recessive hereditary disease. Pyruvate kinase deficiency: is an inherited metabolic disorder of the enzyme Pyruvate kinase which affects the survival of RBCs and causes them to deform into echinocytes on peripheral blood smears.

33 Red cell destruction -Hemolytic Anemia
Congenital Hemoglobin defects: diagnosed by hemoglobin electrophoresis. Thalassemias: Genetic defect in hemoglobin synthesis decreased synthesis of one of the 2 globin chains ( or ) Imbalance of globin chain synthesis leads to depression of hemoglobin production and precipitation of excess globin (toxic) “Ineffective erythropoiesis” Found in people of African, Asian, and Mediterranean heritage Fe stores are usually elevated The only treatments are stem cell transplant and simple transfusion. Chelation therapy (administration of chelating agents to remove heavy metals from the body) to avoid iron overload has to be started early.

34 Red cell destruction -Hemolytic Anemia
Congenital Hemoglobin defects: Sickle cell disease Single base pair mutation results in a single amino acid change. Under low oxygen, Hgb becomes insoluble forming long polymers This leads to membrane changes (“sickling”) and vasoocclusion OXY-STATE DEOXY-STATE

35 Red cell destruction -Hemolytic Anemia
Aquired Classified according to site of RBC destruction and whether mediated by immune system Intravascular Extravascular Autoimmune Non-immune Many causes… be aware of these – Transfusion of incompatible blood Prosthetic valves Cancer Drugs

36 RBCs Disorders - Anemia
Marrow production Thalassemias Myelodysplasia Myelophthisic Aplastic anemia Nutritional deficiencies Red cell destruction (hemolytic) Hemoglobinopathies Enzymopathies Membrane disorders Autoimmune

37 Marrow Production - Aplastic Anemia
Aplastic anemia is a disease in which the bone marrow, and the blood stem cells that reside there, are damaged. This causes a deficiency of all three blood cell types: red blood cells (anemia), white blood cells (leukopenia), and platelets (thrombocytopenia). Acquired Immunological Toxins – Benzene Drugs – methotrexate, chloramphenicol Viruses – EBV, hepatitis Hereditary Fanconi anemia (FA) is the result of a genetic defect in a cluster of proteins responsible for DNA repair

38 Marrow Production - Aplastic Anemia
All lineages affected. Most patients require red cell transfusions. Transplant when possible. Transfusions should be used selectively to avoid sensitization (no family donors!).

39 Polycythemia / Erythrocytosis
Polycythemia is increased total RBC mass - Hct > 65% Above 65% blood viscosity rises exponentially Complications: Polycythemic hyperviscosity is increased viscosity of the blood resulting from increased numbers of RBCs Polycythemia occurs in 2-4% of newborns, half of them are symptomatic Clinical signs result from regional effects of hyperviscosity and from the formation of microthrombi Tissue hypoxia, Acidosis, Hypoglycemia Organs affected: CNS, kidneys, adrenals, cardiopulmonary system, GI tract Treatment Phlebotomy (to cut a vein) is the process of making an incision in a vein . Myelosupressive agents: new therapeutic agents such as: interferon alfa-2b (Intron A) therapy, agents that target platelet number (e.g., anagrelide [Agrylin]), and platelet function (e.g., aspirin).

40 Benign WBCs Disorders

41 Leukopenia (Leukocytopenia) -
Leukopenia: is a decrease in the number of WBCs Neutropenia is most common cause Absolute neutrophil count (ANC) < 1.5 x 109 cells/L Many causes Benign racial neutropenia common African Americans and Yemenite Jews may have ANC as low as 1.0 Viral infections Epstein-Barr, Hepatitis B, HIV Drugs Careful review of medications ; be suspicious of any medication recently started in patient with acute onset neutropenia Splenomegaly Autoimmune disorders SLE (lupus), Rheumatoid Arthritis, etc. Bone marrow disorders

42 Leukocytosis Leukocytosis: is an increase in the number of WBCs
WBC count > 11,000 Determine which type of WBC is leading to the leukocytosis Neutrophilia = most common Causes: Infection Connective tissue disorders Medications (especially steroids, growth factors) Cancer Myeloproliferative disorders Cigarette smoking Stress (physiologic) Pain, trauma Idiopathic (unknown cause)

43 Leukocytosis Patients with acute bacterial infection often present with neutrophilia and band formation Bands = young neutrophils Viral infections are usually associated with low WBCs ; leukocytosis may suggest complications Ex: bacterial pneumonia with underlying influenza infection

44 Leukocytosis Lymphocytosis: is an increase in the number or proportion of lymphocytes in the blood Causes: Viral infections: HBV, HCV, EBV, CMV Tuberculosis Pertussis Drug Reaction Stress (physiologic): Trauma, cardiac arrest, etc Malignancy: ALL, CLL, lymphoma

45 Malignant WBCs Disorders

46 Myeloid vs. Lymphoid Myeloid malignancies • Acute myeloid leukemia
• Chronic myeloproliferative disorders Lymphoid malignancies • B-cell malignancies • Acute lymphoblastic leukemia, B-cell type • Non-Hodgkin’s lymphoma, B-cell types • Myeloma • T-cell malignancies • Acute lymphoblastic leukemia, T-cell type • Non-Hodgkin’s lymphoma, T-cell types • Hodgkin’s disease

47 Leukemia Leukemia is a type of cancer of the blood or bone marrow characterized by an abnormal increase of immature WBCs called “blasts". Leukemia is a broad term covering a spectrum of diseases. In turn, it is part of the even broader group of diseases affecting the blood, bone marrow, and lymphoid system.

48 Chronic Leukemia Chronic myelogenous leukemia (CML)
Translocation between long arms of chromosomes 9 and 22 ; “Philadelphia Chromosome” ; bcr/abl protein

49 Chronic Leukemia Chronic lymphocytic leukemia (CLL)
Clonal malignancy of B-lymphocytes Course is usually indolent ; affects older patients, average age at diagnosis is 70 years Often found incidentally Fatigue, lymphadenopathy common Hepatosplenomegaly Immunodeficiency is major clinical concern Lymphocytes are defective ; do not make antibodies in response to antigens Treatment Observation Indications for therapy include progressive fatigue, symptomatic lymphadenopathy, anemia, or thrombocytopenia Gamma globulin (IVIG) used in patients with recurrent or severe bacterial infections Allogeneic BMT is potentially curative but reserved for select patients Prognosis improving ; survival is years with early disease

50 Acute Leukemia Acute Myelogenous Leukemia (AML) Most common in adults
Usually no apparent cause Exposure to radiation, benzene, and certain chemotherapy drugs (alkylators) associated with leukemia Underlying myelodysplastic syndrome (MDS) is risk factor Symptoms and signs Related to replacement of marrow space by malignant WBCs Patients often very ill for period of just days or weeks Skeletal pain Bleeding Gingival hyperplasia Infection Pancytopenia with circulating blasts is hallmark ; bone marrow biopsy required Auer rods on peripheral smear are pathognomonic

51 Acute Leukemia AML Acute Lymphocytic Leukemia (ALL) Management
Immediate referral to hematologist Patients often hospitalized for therapy Anthracycline (daunorubicin or idarubicin) plus cytarabine results in CR in 80% of patients < 60 years Additional high dose chemotherapy following CR leads to cure rate of 35-40% Acute Lymphocytic Leukemia (ALL) More often seen in children

52 Lymphoma Hodgkin’s disease Malignancy of B-lymphocytes
Reed-Sternberg cells Various subtypes ; “nodular sclerosing” is most common Non-Hodgkin’s Lymphoma (NHL) Heterogeneous group of cancers affecting lymphocytes Usually classified by histologic grade (low to high) Follicular lymphoma Small lymphocytic lymphoma Diffuse large B-cell lymphoma Burkitt’s lymphoma Many others

53 Myeloma Malignancy of plasma cells
Abnormal paraproteins are created leading to systemic problems IgG – 60% IgM – 20% Primarily disease of elderly (median age 65 years) Most common hematologic malignancy among African Americans ; #2 among Caucasians

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