Anemia

Objectives

What is anemia? Diagnostic basis of classification Types and Classification Etiology or Causes of disease Compare and contrast different types of

anemias Polycythemia Why polycythemia occurs

Anemias Diagnostic Classification

1. Kinetic Approach Production vs. destruction or loss

Reticulocyte Production Index (RPI)

2. Morphological Approach Red blood cell size

Microcytic (Cells Smaller than normal size i.e. MCV< 80 fl) Normocytic (Cells Normal sized i.e. MCV = 80-100 fl) Macrocytic (Cells bigger than normal size i.e. > 100 fl)

Concentration of Hb Hyperchromic (Increased Hb Concentration) Normochromic (Normal Hb Concentration) Hypochromic (Decreased Hb Concentration- cells paler

than normal)

Anemia Anemia means deficiency of hemoglobin in the blood

Cause Too few red blood cells or Too little hemoglobin in the cells.

Classification1. Aplastic or Hypoplastic Anemia2. Nutritional Anemia3. Hemolytic Anemia

1. Aplastic or Hypoplastic Anemia Aplastic Loss of bone marrow function Hypoplastic Reduced bone marrow function Anemia due to lack of functioning of Bone Marrow or bone

marrow aplasia. Aplastic anemia patients have lower counts of all three blood cell types: termed pancytopenia.

Characterstics: Decreased Red blood cells Diminished immunity Tendency to bleed

Aplastic Anemia– Causes

– Drugs e.g. (Cytotoxic drugs, some anti convulscent drugs etc)– Radiations (X-Rays)– Chemicals (Benzene and its derivatives)– Viral diseases– Invasion of bone marrow (fibrosis or Leukemia)

Hereditary Congenital hypoplastic anemia (or constitutional aplastic anemia) a

type of aplastic anemia which is primarily due to a congenital disorder (defects or damage to a developing fetus). Examples include:

Fanconi anemia (Caused by short Stature, Skeletal Abnormalities)

Diamond-Blackfan anemia (Congenital Erythroid Aplasia- Characterized by anemia with decreased erythroid progenitors in bone marrow)

Acquired Pure Red cell Aplasia (PRCA) Sideroblastic anemia (Sideroachrestic anemia)1 The body has iron available, but

cannot incorporate it into hemoglobin Myelophthisic anemia2 (Normal marrow space is replaced by nonhematopoietic or

abnormal cells). Cause e.g. tumors

Nutritional Anemia2. Nutritional Anemia

Type of anemia that can be directly attributed to nutritional disorders

Iron Deficiency Anemia (Microcytic) Megaloblastic Anemia (Macrocytic)

Iron Deficiency Anemia (Microcytic) Sideropenic Anemia, cells are smaller in size and paler in colour

Causes: Parasitic Infections

e.g. Hook worms Normal Requirement, Deficient intake

Weight reducing diets, Vegetarian diets High Requirements, Normal or deficient intake

Pregnancy Chronic blood loss (peptic ulcers, menorrhagia,

haemorrhoids, GI carcinoma) Low iron absorption or malabsorption

GI abnormalities Increase in pH (removal of part of stomach) Loss of absorbing surface area (intestine removal)

Nutritional Anemia

Megaloblastic Anemia (Macrocytic) Inhibition of DNA synthesis during erythropoiesis Large, immature RBCs (Megaloblasts)

Characterstics: Immature, fragile cells, Life span b/w 40-50 days Size larger than normal cells, Might contain nucleus

Causes: Hypovitminosis (B12, B9) Antimetabolites that inhibit DNA synthesis e.g.

Purine & Pyrimidine Antagonists (6-Mercaptopurine, Cytosine)

Nutritional Anemia Vitamin B12 deficiency Anemias

Deficient intake in diet (vegetarians) Deficient intrinsic factor (Gestractomy & Pernicious Anemia) Selective B-12 malabsorption (removal of Terminal ileum) Increased needs: pregnancy, infant, rapid cellular proliferation.

Pernicious Anemia Most common form of Vitamin B12 deficiency Anemias Occurs more often in females Cause:

Autoimmune disease results in production of antibodies directed against Intrinsic Factor (IF)* and parietal cells in stomach.

Impaired absorption of vitamin B-12 due to the absence of intrinsic factor as a result of loss of gastric parietal cells.

Treatment IV injections of Vitamin B-12

Complications of B-12 deficiency anemia Appear before the signs of anemia Includes Irreversible neurological damage commonly in spinal

cord (B-12 needed for formation and maintenance of Myelin by schwann cells)

Nutritional Anemia

Vitamin B9 (Folic Acid) deficiency Anemias Deficiency causes megaloblastic anemia but not

associated with neurological damage Causes

Dietary Deficiency e.g. in infants absence or delay of establishing mix diets.

Alcoholism Anorexia (Loss of appetite) Pregnancy (Raised requirement) Malabsorption from jejunum (tropical sprue) Interference with Folate metabolism

Folic acid Antagonists (Methotrexate) Trimethoprim (Antimicrobial agent)

Deficiency Causes neural tube defects during pregnancy*

Folic acid Metabolism

Hemolytic Anemias3. Hemolytic Anemias

Occur when RBCs are destroyed in circulation or removed prematurely from circulation because of abnormal cells or overactive spleen

Hereditary or Congenital hemolytic AnemiasHereditary or Congenital hemolytic Anemias Hemolytic anemia which is primarily due to congenital

disorders Types include:

Genetic conditions of RBC Membrane Hereditary spherocytosis (Sphere shaped RBCs) Hereditary elliptocytosis (Elliptical RBCs) (Also known as ovalocytosis)

Genetic conditions of RBC metabolism (enzyme defects) Glucose-6-phosphate dehydrogenase deficiency (G-6-PD) 1

Pyruvate kinase deficiency (No energy) Hemoglobinopathies / genetic conditions of hemoglobin

Sickle cell anemia Thalassaemia

Hemolytic Anemias Acquired hemolytic anemia

No familial or racial factors have been identified Causes:

Chemical Agents: These agents may cause excessive or early hemolysis

Some Drugs, if taken for long time & in large doses e.g. Sulphonamides

Chemicals faced in general or work environment e.g. lead, arsenic compounds

Toxins produced by certain microbes. e.g. streptococcus pyogenes

Autoimmunity Production of antibodies against self antigens

Blood transfusion Reactions Parasitic Disease e.g. malaria Physical damage to cells by e.g. artificial heart valves, dialysis

machines.

Polycythemia An increase in RBCs number or hematocrit. (65%)

1. Absolute Polycythemia The overproduction of red blood cells in the bone marrow Causes:

Myeloproliferative syndrome, (MPDs)1

Reaction to chronically low oxygen levels Rarely, a malignancy.

Types:1. Primary Polycythemia (Polycythemia vera)

Excess red blood cells are produced as a result of an abnormality of the bone marrow e.g. (Malignancy), (Mutations in JAK2)2

2. Secondary Polycythemia Secondary polycythemia is caused by either natural or artificial increases

in the production of erythropoietin, hence an increased production of erythrocytes.

3. Chuvash Polycythemia (patients from Chuvashia- C598T mutations in (VHL) gene.

Polycythemia

2. Relative Polycythemia Relative Polycythemia is an apparent rise of the erythrocyte level

in the blood Cause: The underlying cause is reduced blood plasma. caused by

loss of body fluids, e.g. in burns, dehydration stress

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