8 Types of Anemia | Based on Morphology & Causes

“Anaemia is an+aemia (no+blood). It is a condition wherein there is decreased oxygen-carrying capacity by the blood.”

Red blood cells carry oxygen to different parts of the body. They have an iron pigment namely hemoglobin to do that.

Anemia can occur either due to a decreased RBC count, decreased hemoglobin or the decreased blood volume. All these lead to the insufficient oxygen-carrying capacity to the tissues and cells by the blood.

RBC’s per deciliter of blood is kept constant to aid proper respiration. When RBC count per mm of blood falls, we experience anemia.

This anemia is mostly found in women and children. The rate of incidence is as below.

  1. Pregnant women (38%)
  2. Children below two years of age (14%)
  3. Elderly people above 65 years (10%)
  4. Women aged between 12 to 49 years (9%)

But of them, anemia is seen mostly in women with abnormal menstruation, during pregnancy and also in children with poor nutrition.

Clinically anemia is of following types like

  1. Normocytic anemia
  2. megaloblastic anemia
  3. microcytic anemia

When blood is examined under a microscope, there are three types of anemia like

Normocytic anemia

Here the Red blood cell size is normal with sufficient levels of hemoglobin. This types of anemia occur due to a decrease in erythrocyte count rather than the changes in RBC. This is caused due to blood loss in injury, menstruation, etc. in many cases. However, it can also be caused due to deficiency of erythropoietin where there is less synthesis or red blood cells in the bone marrow.

Megaloblastic anemia

In this type, the red blood cells are of enormous. They can have sufficient hemoglobin or less. These cells are not fully matured. They are formed with incomplete cell division in the bone marrow leading to bulk than the normal size.

Microcytic anemia is one where the RBC cells are smaller in size than the normal ones. This is mostly due to insufficient hemoglobin levels.

The oxygen-carrying capacity of the blood depends on the hemoglobin portion situated inside red blood cells (RBC’s). So if there is anemia we experience weakness and lack of strength.

These RBC’s are formed in the red bone marrow of the large bones in the body. They have a life span of 120 days. They become fragile due to wear and tear during circulation and get destroyed in the liver and spleen.

The dead ones are replaced by the new RBC’s. The cells formed in the bone marrow are quite large than normal RBC’s and hence vitamins like folic acid and Vit-B12 help in their multiplication to RBC’s.

The causes of anemia are

a) Iron deficiency

b) Vitamin B12 Deficiency

c) Vitamin B9 (folate) deficiency

d) A decrease in blood cell formation

e) Blood loss due to hemorrhage

f) Excessive and premature destruction of red blood cells.

So anemia can occur when there is less volume of blood (in cases like severe bleeding). Due to malnutrition, a decrease in RBC count can occur due to a decreased supply of Vitamins B12 and B9. Decreased hemoglobin content can occur due to lack of iron supplement in food.

Types of anemia scientifically:

1. Aplastic anemia: This is a condition that indicates damage to the red bone marrow of long bones. As we know, the red bone marrow is the site of erythropoiesis, i.e., the formation of blood cells. But due to the effect of radiation or drugs this bone marrow gets damaged. Hence, there is an inability to produce enough RBC’s required for sufficient oxygenation. In severe cases, it may require bone marrow transplantation.

2. Megaloblastic Anemia: As the name indicates, the cells formed are very large.

Types of Anemia
Image showing large sized RBC cell among normal RBC cells.

This is due to the lack of vitamin-12 or folic acid leading to mega RBS. This again happens due to improper multiplication of large cells formed in the bone marrow.

Hence RBC count is low due to improper cell multiplication and production.

Further due to a large size they easily get destroyed and hence their life span is small, unlike normal RBC’s 120 days. Thus overall RBC count falls due to lack of above vitamins. This is otherwise called pernicious anemia if the Vitamin-B12 is deficient. So it is advised to take vitamin supplements after consulting physician.

3. The genetic or hereditary based anemia is less common, but the patient suffers the issue for entire life. This condition can be termed as hemolytic anemia (haemo-related to RBC and Lytic- means breakage), i.e., RBC cells formed are broken down before normal life span of 120 days. This destruction in a short time leads to decreased RBC count. The damage is due to their weak or fragile and abnormal structure instead of normal biconcave. Examples include

Types of anemia-sickle anemia4. Sickle cell anemia: As the name indicates the RBC’s formed are sickle-shaped instead of biconcave.

Due to abnormal shape, they are easily susceptible to endoplasmic reticulum destruction in the liver and spleen.

Thus their life span is small and less than usual RBC’s of 120 days.

They get destroyed and have a short life span, so the RBC count remains low leading to anemia.

5. Spherocytosis anemia: Here the cells are spherical shaped, and they follow the pattern of sickle cell anemia. Similar to above they have short life spans.

6. Decreased Hemoglobin content: Here the RBC cells are devoid of sufficient hemoglobin. This can be due to dietary protein insufficiency or else decreased iron content.

Ex: Hypochromic or microcytic anaemia+ hypo+chromic=less colored and mircocytic= small cell size. As we see, this is type anemia due to low iron levels in the body. There are moderate amounts of hemoglobin due to iron deficiency such that cells are small and blood looks pale.

7.Hemorrhagic Anemia; This happens when there is hemorrhage due to an accident or during delivery etc. Here total blood volume including RBC number is low. This is seen in women in most cases as they lose blood even due to the menstrual cycle. This blood loss anemia can be rectified by transfusion.

8. Anemia due to less RBC count:  This is a type of anemia where there is no sufficient number of red blood cells. This is due to a lack of production of RBC or excess destruction of RBC.

This type of anemia includes aplastic anemia megaloblastic, pernicious anemia.  Further types include genetic related anemic conditions like sickle anemia, hereditary spherocytosis, erythroblastosis fetalis, etc.

For immediate rescue, RBC cells are transfused to the patient. But in the long run, the effort is to enhance new RBC formation.

Symptoms of anemia include:

Most symptoms go unnoticed, but sometimes there can be

1. Fatigue: Exhaustion due to physical exertion as blood is unable to supply needed oxygen for chemical energy production.

2. Headache: This could be due to an insufficient supply of oxygen to the brain.

2. Paleness of mucous membranes like that below the eyelids etc.

3. In extreme conditions during exercise, the heart rises the cardiac output (volume of blood pumped) to meet the excess oxygen demands of the body. In doing so, there can be chances of cardiac failure and death.

One can avoid anemia by proper diet, leafy vegetable consumption and also iron supplements. If one has a vitamin deficiency, it has to be corrected immediately. Sometimes though vitamin-B12 is consumed by external supplements, still the gut may not observe it. So it is advised to consult a physician if the symptoms are troublesome.

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