CLASSIFICATION OF ANEMIA

Javid IqbalBSc(Hons)Medical Laboratory TechnologyTrainee Technologist

Definition of Anemia Deficiency in the oxygen-carrying capacity

of the blood due to a diminished erythrocyte mass.

May be due to: Erythrocyte loss (bleeding) Decreased Erythrocyte production

low erythropoietin Decreased marrow response to erythropoietin

Increased Erythrocyte destruction (hemolysis)

Measurements of Anemia Hemoglobin = grams of hemoglobin per 100 mL of

whole blood (g/dL) Hematocrit = percent of a sample of whole blood

occupied by intact red blood cells RBC = millions of red blood cells per microL of whole

blood MCV = Mean corpuscular volume

If > 96 → Macrocytic anemia If 76 – 96→ Normocytic anemia If < 76 → Microcytic anemia

RDW = Red blood cell distribution width = (Standard deviation of red cell volume ÷ mean cell

volume) × 100 Normal value is 11-15% If elevated, suggests large variability in sizes of RBCs

Laboratory Definition of Anemia

Hgb: Women: <11.5 Men: < 13.7

Hct: Women: < 36 Men: <41

Symptoms of Anemia Decreased oxygenation

Exertional dyspnea Dyspnea at rest Fatigue Bounding pulses Lethargy, confusion

Decreased volume Fatigue Muscle cramps Postural dizziness syncope

RBC Life Cycle In the bone marrow, erythropoietin

enhances the growth of differentiation of burst forming units-erythroid (BFU-E) and colony forming units-erythroid (CFU-E) into reticulocytes.

Reticulocyte spends three days maturing in the marrow, and then one day maturing in the peripheral blood.

A mature Red Blood Cell circulates in the peripheral blood for 100 to 120 days.

Under steady state conditions, the rate of RBC production equals the rate of RBC loss.

Classification of Anemia Anemia can be either acute or chronic. In acute anemia (sudden loss of blood), the lack of blood

volume in the circulatory system is more important than the deficiency of hemoglobin. A loss up to 10% of blood volume, as that taking place upon blood donation, is well tolerated. Losses between 10 and 20% cause postural hypotension, dizziness and faint. In losses above 20%, there's tachycardia, cold extremities, extreme paleness and hypotension, followed by shock; should the loss surmount 30%, without immediate replacement of intravenous fluids, the shock rapidly becomes irreversible and fatal.

In chronic anemia, there's no decrease in blood volume, which is compensated by an increase in plasma volume

Classification of Anemia on the Basis of MCV

Microcytic anemia(MCV<76) Normocytic anemia(MCV=76-96) Macrocytic anemia(MCV>96)

Classification Based on underlying Process

Blood loss or def. of nutrients Hemolysis Failure of production

Classification of Anemia One way to classify anemia is by RBC size (i.e., MCV), as

microcytic, macrocytic, or normocytic. For the microcytic anemias, the etiologic possibilities are iron deficiency, thalassemia, sideroblastic anemia, and the anemias of chronic disease. Severe microcytic anemia (MCV <70 fL) is caused mainly by iron deficiency or thalassemia. Macrocytic anemia may be the result of megaloblastic (folate or vitamin B12 deficiency) or nonmegaloblastic causes. Folate deficiency can in turn be due to either reduced intake or diminished absorption. Severe macrocytic anemia (MCV >96fL) is almost always megaloblastic. In some rare cases, macrocytic anemia is related to the myelodysplastic syndromes prior to or after chemotherapy.

The causes of normocytic anemias include aplastic anemia, bone-marrow replacement, pure red-cell aplasia, anemias of chronic disease, hemolytic anemia, and recent blood loss. A number of anemias have a genetic etiology. Examples of such inherited disorders include hereditary spherocytosis and sickle-cell (SC) anemia

Hypochromic Microcytic Anemia

Microcytic anemias the etiologic possibilities are Iron deficiency Thalassemia Sideroblastic anemia Anemias of chronic disease. Severe microcytic anemia (MCV <76 fL) is caused mainly by iron deficiency or thalassemia.

Iron Deficiency Anemia

Iron Deficiency Anemia - koilonychia

Iron Deficiency Anemia – Lab Findings

Serum Iron LOW (< 60 micrograms/dL)

Total Iron Binding Capacity (TIBC) HIGH ( > 360 micrograms/dL)

Serum Ferritin LOW (< 20 nanograms/mL) Can be “falsely”normal in inflammatory

states

TEST Iron def ThalMin An of ch dis S.Iron - low normal normal S.Ferritin - low N/H N/H Marrow iron - low N/H N/H Hb A2 or F - N H=Bthal N N=Athal RDW - high normal N/H

Thalassemia Microcytic anemia Defects in either the alpha or beta chains of

hemoglobin, leading to ineffective erythropoiesis and hemolysis -thalassemia:

Prevalent in Africa, Mediterranean, Middle East, Asia

-thalassemia: Prevalent in Mediterranean, South East Asia,

India, Pakistan Smear shows microcytosis with target cells

Thalassemia

Normochromic Normocytic Anemia

Chronic inflammatory disease—(1)infection (2)collagen vascular disease (3)inflammatory bowel disease

Recent blood loss Malignancy/Marrow infiltration Chronic renal failure Transient erythroblastopenia of chidhood Marrow aplasia/hypoplasia HIV infection

The causes of normocytic anemias include aplastic anemia, bone-marrow replacement, pure red-cell aplasia, anemias of chronic disease, hemolytic anemia, and recent blood loss. A number of anemias have a genetic etiology. Examples of such inherited disorders include hereditary spherocytosis, sickle-cell (SC) anemia, and thalassemia

Normochromic Normocytic

Macrocytic Anemia Megaloblastic anemias • Vit.B12 def. - (1) pernicious anemia (2) malabsorption • Folate def. - (1) malnutrition (2) malabsorption (3) chronic hemolysis (4)drugs - phenytoin, sulfa Hemolysis Myelodysplastic syndrome Marrow failure - Aplastic anemia Chronic liver disease Hypothyroidism

Vitamin B12 Deficiency

Macrocytic anemia may be the result of megaloblastic (folate or vitamin B12 deficiency) or nonmegaloblastic causes. Folate deficiency can in turn be due to either reduced intake or diminished absorption. Severe macrocytic anemia (MCV >125 fL) is almost always megaloblastic.

Folate Deficiency

Vitamin B12 Deficiency Versus Folate Deficiency

Vitamin B 12 Deficiency

Folate Deficiency

MCV > 100 > 100

Smear Macrocytosis with hypersegmented neutrophils

Macrocytosis with hypersegmented neutrophils

Pernicious anemia Yes NO

Homocystine Elevated Elevated

Methylmalonic Acid Elevated NORMAL

Anemia due to Destruction of Red Blood Cells

Hemoglobinopathies Sickle Cell Anemia

Aplastic Anemia Decrease in all lines of cells – hemoglobin,

hematocrit, WBC, platelets Parvovirus B19, EBV, CMV Acquired aplastic anemia

Hemolytic Anemia

Hemolytic Anemias Hereditary spherocytosis Glucose-6-phosphate

dehydrogenase (G6PD) Deficiency

Most common enzyme defect in erythrocytes

X-linked Brisk hemolysis when patients

exposed to oxidative stress from drugs, infections or toxins.

Thrombotic Thrombocytopenic Purpura (TTP)

Thrombocytopenia and microangiopathic hemolytic anemia, fever, renal insufficiency, neurologic symptoms

Schistocytes on smear Hemolytic Uremic Syndrome

Thrombocytopenia, Microangiopathic hemolytic anemia, renal insufficiency

Autoimmune Hemolytic Anemia Warm-antibody mediated

IgG antibody binds to erythrocyte surface

most common Diagnosed by POSITIVE Coomb’s

Test (detectgs IgG or complement on the cell surgace)

Can be caused drugs Treated with corticosteroids or

splenectomy if refractory Cold agglutinin Disease

IgM antibodies bind to erythrocyte surface

Does not respond to corticosteroids, but usually mild.

Infections Malaria Babesiosis Sepsis

Trauma Includes some snake, insect bites

Sickle Cell Anemia

Spherocytosis

Malaria