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Definition of Anemia

Anemia classification on the basis of RBC morphology:

  1.  Normochromic and normocytic anemias are due to:
    1. Anemia of acute hemorrhage.
    2. Hemolytic anemia.
    3. Anemia due to chronic diseases.
  2. Hypochromic and microcytic anemias are due to:
    1. Iron deficiency anemia.
    2. Thalassemia.
  3. Normochromic and macrocytic anemias are due to:
    1. Vit. B12 deficiency.
    2. Folate deficiency.

Anemia classification on the basis of physiological abnormality:

  1. Defective maturation of erythropoiesis.
  2. Hemolytic anemia where this is the increased breakdown of the RBCs.
  3. Defect due to an increase in RBC precursors as compared to the degree of anemia.

Amenia classification on the basis of etiology:

  1. Increased RBCs destruction due to intra or extra red blood cells defects.
  2. Increased blood loss which may be acute or chronic.
  3. Defective RBCs formation due to Lake of factors necessary for erythropoiesis.

Indications for the tests of Anemias:

  1. Hemoglobin when it is less than 12 to 13 G/dL.
  2. Hematocrit when it is less than 36 to 41%.
  3. Reticulocytes count were normal 0.5 to 1.5%.
  4. If MCV is high then advise:
    1. Reticulocytes count.
    2. Vit.B12.
    3. Folate level.
  5. If MCV is low advised:
    1. Serum Iron.
    2. Iron binding capacity (TIBC).
    3. If the above two tests are low then advise Ferritin and Bone marrow examination.
    4. If normal then advise electrophoresis.
  6. If MCV is normal then advise:
    1. Serum Iron.
    2. Iron Binding Capacity. (TIBC).
    3. Comb's test.
    4. Peripheral blood for RBC morphology.

Routine workup of the patient with anemia, advise:

  1. Hemoglobin and hematocrit.
  2. Red blood cell count.
  3. Blood indices.
  4. peripheral blood smear.
  5. Reticulocyte count.
  6. White blood cells count and platelets count.

Types of Anemias

Normochromic, Normocytic Anemia findings are:

  1. Low hemoglobin.
  2. Normal MCV 80 to 95 fL.
  3. Normal MCH ≥27 pg.
  4. Normal MCHC.
    1. Mostly these are due to acute blood loss.
  5. Causes are:
    1. Iron deficiency in the early stages.
    2. Acute blood loss.
    3. Chronic diseases like neoplasia and infections.
    4. Drugs like chloramphenicol cause aplastic anemia.
    5. Acquired hemolytic anemia which may be from the prosthetic surgery of heart.

Microcytic, hypochromic anemia finding is:

  1. Low hemoglobin.
  2. Low MCV <80 fL.
  3. MCH < 27 pg.
  4. Causes are:
    1. Iron deficiency anemia.
    2. Lead poisoning.
    3. Thalassemia.

Microcytic, normochromic anemia findings are:

  1. Low hemoglobin.
  2. The cause is renal diseases.

Macrocytic Anemia findings are:

  1. Low hemoglobin.
  2. MCV > 99 fL.
  3. Peripheral blood smear shows macrocytosis and many hypersegmentation of neutrophils.
  4. Occasionally may see leucopenia and thrombocytopenia.
  5. Causes are:
    1. Vitamin B12 deficiency.
    2. Folic acid deficiency.
    3. Chemotherapy side effects.
    4. In the case of hydantoin therapy.

Megaloblastic Anemia findings are:

  1. Hemoglobin is typically low (may reach 2 g/dL)
  2. Increased MCV (>95 fl)
  3. Peripheral blood smear show anisocytosis, poikilocytosis with the presence of Macrocytes.
    1. May see nucleated RBCs.
    2. There are hypersegmented neutrophils.
    3. This is due to B12 and Folate deficiency.

                                                             

 Hemolytic Anemia findings are:

  1. There is raised bilirubin level.
  2. There are increased reticulocytes.
  3. There is polychromasia. 

                                                           

                                                                                            Polychromasia in Hemolytic anemia

Iron deficiency Anemia findings are:

  1. Low hemoglobin.
  2. Low Ferritin.
  3. Low serum iron.
  4. Low transferrin.
  5. Raised TIBC.
  6. Low MCV.
  7. Low MCHC or normal.
  8. Generally increased RDW.
  9. Peripheral blood smear shows:
    1. Microcytosis and hypochromasia.
    2. There is anisocytosis, poikilocytosis.
    3. There are pencil cells (elliptical RBCs).

                                                            

                                                                                               Microcytic hypochromic anemia

 

 

Hereditary Spherocytosis findings are:

  1. There is mild to moderate anemia ( 8 to 12 G/dL).
  2. Increased reticulocytes.
  3. Peripheral blood shows prominent spherocytes.
    1. Reticulocytes are seen.

                                                           

Glucose-6-Phosphate Dehydrogenase Deficiency anemia findings are:

  1. Hemoglobin is low in the hemolytic crises.
  2. Peripheral blood smear shows poikilocytosis.
    1. RBCs with punched-out defects in their shapes are seen.
    2. Spherocytes may be seen.
  3. Diagnosed by a screening test for G-6-PD deficiency.
  4. Definite diagnosis by enzyme assay.

Thalassemia findings are:

  1. Low Hemoglobin.
  2. Peripheral blood smear shows Hypochromic and microcytic anemia.
  3. Hb electrophoresis confirms the diagnosis by the near absence of the decreased level of Hb A.

  1. Thalassemia has two types:
    1. α-Thalassemia trait is due to double gene deletion.
      1. There are microcytes and hypochromasia.
    2. α-Thalassemia disease is due to three gene deletion.
      1. There are target cell, ovalocytes, microcytes, and Hb H inclusion in the TBCs.
    3. β- Thalassemia in heterozygotes and there is β gene deletion alone either alone or in combination with δ gene.
      1. There are microcytes, target cells, elliptocytes, and basophilic stippling.
    4. β- Thalassemia in homozygotes and there is β gene deletion either alone or in combination with δ gene.
      1. It is marked hypochromasia with polychromatic rims.  There are target cells, ovalocytes, basophilic stippling, and HbH crystals.

                                                      

                                                                              Hypochromic and microcytic RBC and teardrop cells

Sickle Cell Anemia findings are:

  1. Low hemoglobin (7 to 9 G/dL).
  2. Peripheral blood smear shows sickled RBCs.
  3. Electrophoresis of blood show Hb S and no normal Hb A.

Sideroblastic anemia findings are:

  1. Hemoglobin is low.
  2. MCV is variable.
  3. RDW is increased.
  4. There are normocytic and as well as microcytic and hypochromic RBCs. Occasional macrocytes are seen. 
    1. This may be congenital or drug-induced.
    2. This may be seen in malignancies or malabsorption.

Anemia due to chronic diseases findings are:

  1. There is Low hemoglobin.
  2. MCV is normal.
  3. RBCs may be normal or microcytic and hypochromic RBCs.
    1. This is seen in collagen diseases (autoimmune diseases) and inflammatory conditions.

Table showing findings in various anemias

Type of anemia Hb MCV MCH MCHC
Iron deficiency low low low low
Megaloblastic low high high normal
Thalassemia low low low low

Chronic illness

low low low low                     


Characteristic findings in various Anemias
                            

Anemia type
HB        
MCV 
MCH
MCHC        
Ferritin 
Iron binding capacity           
serum iron
 RDW
Iron deficiency           low

low <76 fl

low low/normal decreased increased decreased   increased 
Megaloblastic low high >100 fl/cell    

increased

>32 pg

low 32 to 36 g/dL

     raised/normal increased
Chronic illness low low/normal low low normal/ increased normal / decreased decreased normal
Alpha Thalassemia low or normal low low low

 normal /increased

 normal

 normal or 

increased

increased
Beta Thalassemia low low low low  increased/normal  normal  increased/normal  increased
Aplastic anemia low increased normal   normal       normal

 

Classification of anemia on the basis of RDW:

 Cell size                        
Normal RDW                         
High RDW
   Microcytosis           

Thalassemia minor, Chronic diseases,

and some hemoglobinopathy trait                    

Iron deficiency, Hb H, anemia of chronic diseases,
some cases of thalassemia.

   Normocytic


 Hereditary spherocytosis, acute bleeding,

some chronic diseases, some Hb traits

Some early or partially treated iron deficiency anemia
Sickle cell anemia
   Macrocytosis Aplastic Anemia  Autoimmune hemolytic anemia, vit.B or folate deficiency
Liver disease, thyroid disease, myelodysplasia, and alcohol use

Possible References Used

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