Anemia and its type

  • A condition in which the number of red blood cells, the normal concentration of hemoglobin, or the hematocrit is below normal is called anemia.
  • It decreases the blood’s oxygen carrying capacity.
  • Anemia is usually a symptom of underlying diseases.
  • There is usually an abnormally high amount of bilirubin in the plasma when anemia is due to the excessive destruction of erythrocytes.
  • It results in producing characteristics jaundice of the skin and darkening of the feces.
  • The various types of anemia are:

1. Hemorrhagic anemia

  • Results from heavy blood loss.
  • Can be acute and chronic type.
  • Might be seen in some cases like heavy blood loss in menstrual bleeding.
  • Also in severe wounds, or the sort of internal bleeding that accompanies a serious stomach ulcer.

In acute type

  • Hemodilution occurs due to less number of RBC’s.
  • After loss of blood, plasma of blood replaces within 24 hour.
  • But, RBC’s takes at least 4-6 weeks.
  • RBC’s are normocytic and normochromic morphologically.
  • Decrease RBC’s results to hypoxia.
  • Thus, hypoxia causes production of more number of RBC’s by stimulating bone marrow.
  • Correction in the count of RBC’s occurs within 4-6 weeks.

In chronic type

  • Results due to long time loss of blood either externally or internally.
  • Lot of iron is lost resulting to iron deficiency.
  • Hemoglobin synthesis thus affected decreasing its amount in cells.
  • This results to decrease in cell size.
  • RBC’s are microcytic and hypochromic morphologically.

2. Iron-deficiency anemia

  • It is the most common type of anemia.
  • It may be caused by long-term blood loss, low intake of iron, or faulty iron absorption.
  • A hypochromic (low concentration of iron in erythrocytes) microcytic (small erythrocytes) anemia develops if there is deficiency of iron to make erythrocytes.

3. Aplastic anemia

  • Characterized by failure of bone marrow to function normally.
  • Generally caused by poisons such as lead, benzene or arsenic that hampers the production of RBC’s.
  • It might be caused by radiation such as x-rays or atomic radiation that damages the bone marrow.
  • Improper functioning of bone marrow results in drastic decrease in total count of erythrocytes and leukocytes.
  • Viral infections, bacterial toxins, tuberculosis also cause this anemia.
  • Morphologically, RBC’s are normocytic and normochromic.


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4. Hemolytic anemia

  • It occurs in case of infecting organisms such as the malarial parasites.
  • As it enters the blood cells it reproduces until the cells actually burst.
  • Such a rupture is called hemolysis (blood destruction), which causes the anemia.
  • It might be hereditary or due to sickle cell anemia or an adverse reaction to a drug.
  • Thalassemia is the name of group of hereditary hemolytic anemias.
  • Impaired hemoglobin production is noticed which results in impaired erythrocyte production.
  • It is most common in people of Mediterranean descent.
  • Sickle cell anemia is another hereditary hemolytic anemic condition.
  • Classified into two types.

Extrinsic hemolytic

  • External factors destroy RBCs in this type.
  • Antibodies, chemicals and drugs outside the blood cells hemolize healthy RBCs.
  • Also called autoimmune hemolytic anemia.

Causes of external hemolytic anemia

  • renal disorder
  • hyper-splenism
  • burns
  • hepatitis, malaria and septicemia like infections
  • various drugs like penicillin, sulfa drugs
  • chemical substances poisoning like lead, coal and tar
  • iso-aglutinins like anti-Rh
  • autoimmune diseases like ulcerative colitis.
  • liver failure, etc.

Intrinsic hemolytic anemia

  • defective RBCs cause destruction of other normal RBCs.
  • production of unhealthy RBCs with short life occurs in this type.
  • destruction of these unhealthy RBCs takes place soon.
  • often inherited type of anemia which includes sickle cell anemia and thalassemia.
  • in this type, RBCs become more fragile(weak) and susceptible for hemolysis.


Image result for types of anemias

Sickle cell anemia

  • It generally occurs in Blacks i.e., It affects 1 in 600 American blacks.
  • It is a genetic hemolytic anemia.
  • It results from the inheritance of the hemoglobin S-producing gene, which results in substitution of the amino-acid valine for glutamic acid in two of the four chains that compose the hemoglobin molecule.
  • The abnormal red blood cells become rigid, rough and crescent shaped like a sickle so named sickle cell anemia.
  • Sickle cells do not carry or release oxygen as well as normal erythrocytes do.
  • Blood becomes more viscous by clogging of capillaries and other small blood vessels.
  • It reduces the blood supply to some tissues thus producing swelling, pain and tissue destruction.
  • Effective treatment has not been discovered yet.
  • It might result to chronic fatigue and pain, increased susceptibility to infection, decreased bone marrow activity, and even death.

Image result for types of anemias  Sickle Cell Anemia - The Medical Biochemistry Page

Image source: themedicalbio


  • Inherited disorder with abnormal hemoglobin.
  • Also called Cooley’s anemia or mediterranean anemia.
  • Common in countries like Thailand and some Mediterranean countries.
  • Two types: α and β thalassemia.
  • More common type is β thalassemia.
  • Number of α  and β polypeptide chains is equal in case of normal hemoglobin.
  • But, these number get imbalanced in this anemia condition.
  • This is due to synthesis of globin genes in defective way.
  • Thus, results in precipitation of polypeptide chains in the immature RBCS.
  • In turn, erythropoiesis gets disturbed.
  • Also, precipitation occurs in mature red cells resulting in hemolysis.

α- thalassemia

  • Common in fetal life or in infancy.
  • Less, absence or abnormal α- chains present.
  • β chains are more in adults and γ chains are more in children.
  • Thus, defective erythropoiesis results and finally hemolysis.
  • Death of infants may occur immediately after birth or the case of stillborn noticed.


  • β- chains less absent or abnormal and excess of alpha chains present.
  • α chains precipitate leading to defective erythropoiesis.
  • Thus, finally hemolysis occurs.

Beta thalassemia: MedlinePlus Genetics

Image source: medlineplus

5. Pernicious anemia

  • Also called Addison’s anemia.
  • Caused by improper absorption of dietary vitamin B12.
  • It is required for the complete maturation of the red blood cells.
  • Antibodies are associated in major cases which destroy intrinsic factor in the stomach mucosa.
  • Intrinsic factor is a protein that combines with vitamin B12.
  • Thus, facilitates its absorption by the small intestine.
  • In absence of intrinsic factor, immature red blood cells accumulate in the bone marrow.
  • The mature blood cells count may drop as low as below 20% of normal, and immature cells enter the circulation.
  • If diagnosed on time, it can be treated successfully with intramuscular injections of vitaminB12 and an improved diet.
  • If left untreated, the disease may affect the nervous system causing decreased mobility, general weakness, and damage to the brain and spinal cord.
  •  Common in old age and in females than in male.
  • Disorders of thyroid may also cause this type of anemia.
  • Lemon yellow colour of skin and red sore tongue are common features.
  • Sensation of numbness, tingling, burning, etc. are some associated neurological disorders.
  • Ataxia i.e., muscular incoordination observed in extreme conditions.


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6. Megaloblastic anemia

  • Folic acid deficiency causes this type of anemia.
  • One of the essential maturation factor of RBCs.
  • Deficiency condition does not allow RBCs to mature.
  • Thus, characterized by defective DNA synthesis due to which nucleus remains immature.
  • Megalobalstic and hypochromic RBCs are observed.
  • Features similar to that of pernicious anemia.
  • However, disorders related to neurons are not observed.

(Note: Nutrition deficiency anemia types are iron-deficiency anemia, pernicious anemia and megaloblastic anemia)




Anemia and its type