Anemia, Types, Causes, Symptoms, And Treatment

In anemia, the level of hemoglobin in your blood is reduced. Hemoglobin is a protein found in red blood cells. It carries iron and iron is responsible for holding oxygen. It is an important component of blood. Its normal value in females is 12 or higher and in males is 13 or higher. According to the World Health Organization, the level of hemoglobin in males is less than 13g/DL or in females less than 12g/DL is considered anemia. The oxygen-carrying capacity of blood is reduced in anemia due to a reduction in hemoglobin level. It is not a disease but a condition or result of different medical conditions. Anemia is reported in over 50% of pregnant women and over 40% of infants globally.

Most Common Types Of Anemias

The anemias are classified on the basis of mean corpuscular volume into three main types. Mean corpuscular volume is the average volume of red blood cells in a specimen of blood. Mean corpuscular volume is decreased or increased according to the size of red blood cells. The normal value of the mean corpuscular volume is 80-96 femtoliters or fL/red cells in adults.

These three types of anemias include the following,

1. Microcystic Anemias

The value of the mean corpuscular volume is decreased in these types of anemias. These types include iron deficiency anemia, anemia of chronic diseases, and sideroblastic anemia.

2. Macrocystis Anemias

The value of the mean corpuscular volume is very high in these types of anemias. They are also known as megaloblastic anemias. These types include folate deficiency anemia and vitamin B12 deficiency anemia.

3. Hemolytic Anemias

The rate of destruction of red blood cells is much faster than their production. These cells carry oxygen to all body parts. The destruction of red blood cells is called hemolysis. These types include autoimmune hemolytic anemia, thalassemia, sickle cell anemia, and glucose 6 phosphate dehydrogenase deficiency anemias.

Explanation Of These Types

1. Iron Deficiency Anemia

This type is the most common type of anemia. It is caused by hemorrhoids, nose bleeding, gastrointestinal bleeding, hemorrhage, and inadequate absorption of iron.

2. Anemia Of Chronic Diseases

It is the second most common type after iron deficiency anemia. It is caused by other inflammatory conditions such as arthritis, inflammatory bowel diseases, HIV infection, and malignancies. It is also called anemia of inflammation.

3. Sideroblastic Anemia

In this type, the bone marrow produces ringed sideroblasts rather than normal healthy red blood cells.  It may be either a hereditary condition or can be acquired from other conditions and drugs.

4. Macrocystis Anemias

The main defect in macrocytic anemia is the inhibition of DNA synthesis in maturing cells. There is also an abnormality reported in the maturation of hematopoietic cells in the bone marrow. The other causes include folate and vitamin B12 deficiency.

5. Hemolytic Anemias

The lifespan of erythrocytes in hemolytic anemias is reduced. The rate of reduction of erythrocytes exceeds the rate of production.

6. Sickle Cell Anemia

In this type, there is a different shape of hemoglobin HbS rather than the normal shape of hemoglobin HbA. It is a hereditary condition. The shape of hemoglobin becomes like the shape of a sickle. This sickle-shaped hemoglobin die before maturation leading to anemia.

7. Autoimmune Hemolytic Anemia

In this type of anemia, there is an abnormal production of antibiotics that binds to an antigen on the surface of the erythrocyte. These antibiotics reduced the life span of red blood cells.

8. Glucose 6 Phosphate Dehydrogenase Deficiency Anemias

In this type, a defect is reported in the glucose 6 phosphate dehydrogenase enzyme that causes the premature breakdown of red blood cells. This process of breakdown is called hemolysis.

9. Thalassemia

It is a hereditary condition. It is a group of autosomal recessive diseases. There are two main types of thalassemia, alpha, and beta-thalassemia. In alpha thalassemia, the production of alpha chains is absent or reduced. While in beta-thalassemia, the production of the beta chain is reduced or absent. Alpha type is more common than beta type.

Causes

The decreased level of hemoglobin in anemia is caused by two different mechanisms of action.

• First is the reduction of hemoglobin synthesis
• Second is the increased loss of hemoglobin

Synthesis of hemoglobin is reduced due to either the lack of nutrients or by the failure of bone marrow. When the synthesis of hemoglobin is reduced, the maturation of precursors defects and proliferation of precursors is reduced. The loss of hemoglobin is increased due to either hemorrhage or hemolysis. There is a great loss of red blood cells in the hemorrhage. In hemolysis, the destruction of red blood cells occurs.

Symptoms

The clinical presentation of anemia includes the following symptoms,

• Tiredness
• Lethargy
• Pale skin
• Chest pain
• Fatigue
• Dysphagia
• Shortness of breath
• Glossitis
• Pallor
• Fainting
• Dyspnoea
• Tachycardia
• Palpitations
• Worsening angina and cardiac failure
• Reduced mental performance
• Inhibition of physical exercise
• Death (in severe cases)

Treatment

Oral supplementation of iron is recommended for the treatment of iron deficiency anemia. The standard dose is 150-300mg two to three times a day in iron deficiency anemia. The underlying cause of anemia is treated in anemia of chronic diseases. The standard therapy includes intravenous iron in combination with erythropoietin analogs for patients with chronic kidney disease. Intravenous iron is recommended in patients with arthritis or inflammatory bowel disease. The drugs or vitamins used for the treatment of sideroblastic anemia include thiamine, folic acid, and pyridoxine B6. If the patient is not responding to these drugs, then blood transfusions are needed. Folic acid is used in doses of 5-15mg in a day and pyridoxine in the doses of 100-200mg daily. Folate and vitamin B6 deficiency is mainly reported in megaloblastic anemia. The standard treatment plan includes hydroxocobalamin 1mg intramuscularly three times a week for the duration of two weeks and then 1mg every three months. Folate deficiency replacement therapy for 4 months and vitamin B6 deficiency lifelong replacement therapy are also recommended. Folic acid supplements are used for the treatment of hemolytic anemia. The dose of folic acid is 5-15mg a day. If the patient does not respond to treatment, then blood transfusions are needed. Antibiotics such as penicillin and erythromycins are used for the prevention of infection in sickle anemia.  Antimetabolites, folic acid supplements, and analgesics are also used. Pneumococcal vaccination and Haemophilus influenza vaccination are also recommended. The standard treatment plan for autoimmune hemolytic anemia is high-dose corticosteroids and anti-CD20 monoclonal antibodies such as rituximab. Immunosuppressive agents such as cyclophosphamide or cyclosporine are also effective. Blood transfusions are also recommended.Blood transfusions are proved to be life-saving for the treatment of glucose 6 phosphate dehydrogenase deficiency anemia. It is better to treat the underlying cause. Offending drugs and splenectomy are not effective in this type of anemia. Blood transfusions, folic acid, and splenectomy are used for the treatment of thalassemia.