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Anemia Pathophysiology & Schematic Diagram

A. Definition

Anemia is a condition where red blood cells are not providing adequate oxygen to body tissues. Red blood cells provide oxygen to body tissues. There are many types and causes of anemia.

B. Causes

Anemia is caused by many different things at it has a lot of subtypes. However, the main presenting factor is the lack of healthy circulating red blood cells to carry oxygen systemically. Here is a quick overview of the different subtypes of anemia:

1. Iron Deficiency Anemia

Iron is needed for healthy production of red blood cells. Iron is a building block of healthy red blood cells. A deficiency in iron would result in immature, microsomic, and hypochromic red blood cells. Also, fewer RBCs will be produced by the marrow. This type of anemia is the most common type of anemia.

2. Folic-Acid Deficiency Anemia

Folate is also known as Folic Acid. This type of anemia results from a deficiency of this B vitamin. This particular type of anemia is particularly common among pregnant women as the developing fetus uses up the mother’s folate stores. In folate deficiency anemia, the red blood cells are macrosomic and are called megalocytes or megaloblasts. This is the reason why this form of anemia is called Megaloblastic Anemia

3. Thalassemia

Thalassemia is a form of anemia that is inherited. In this type of anemia, the body makes an abnormal form it hemoglobin, the major protein in RBCs that carry oxygen. In alpha-thalassemia, the genes related to alpha globin are mutated or are missing. In beta thalassemia, a gene defect also affects the production of beta globin. Thalassemia major is categorized if you inherit the genetic defect from both parents. If only one parent however transmits the defect, it is termed Thalassemia minor. Both conditions result to an abnormal form of hemoglobin and leads to excessive RBC destruction leading to anemia.

4. Vitamin B12 Deficiency Anemia

This form of anemia is due to lack of sufficient cyanocobalamin or Vitamin B12. This type of anemia results to macrosomic, hypochromic RBCs. This is often referred to as Pernicious anemia. The cause of this type of anemia could be a dietary deficiency, or a disease that impairs its proper absorption such as  Celiac disease or Crohn’s disease.

5. Hemolytic Anemia

Hemolytic Anemia is a type of anemia that results from excessive lysis or destruction of RBCs. This type of anemia has a lot of causes and it also has different subtypes. The destroying factor may be intrinsic, or extrinsic, depending on the specific cause. In this type of anemia, RBCs are rapidly destroyed, resulting to a low number of oxygen-carrying RBCs leading to anemia. This type of anemia does not occur though if the bone marrow is capable of producing much more RBCs than those destroyed.

6. Aplastic Anemia

In Aplastic anemia, there is a deficiency in sufficient production of red blood cells by the bone marrow. There are two types of this: idiopathic, or secondary. In idiopathic aplastic anemia, there is no clear cause as to why the bone marrow is unable to produce new, mature red blood cells. In secondary aplastic anemia, the failure results as a sequel from another disorder such as renal disease (where there is decreased erythropoietin), chemotherapy, radiation, and others.

7. Sickle-Cell Anemia

This type of anemia is caused by a particular type of hemoglobin called hemoglobin S. Hemogloin S changes the shape of red blood cells especially during times of low oxygen saturation of the blood. Hemoglobin S causes cells to become shaped like sickles or crescents. These RBCs are unable to properly carry oxygen, and they often get lodged into capillaries and block them.

C. Symptoms

Symptoms of anemia may vary from the specific subtype, but these are some of the general signs and symptoms:

  • Fatigue
  • Pallor
  • Cyanosis
  • Low hematocrit and RBC levels on a Complete Blood Count
  • Chest pain
  • Dizziness and Headaches
  • Paresthesia
  • Skin mottling
  • Shortness of Breath
  • Confusion and restlessness
  • Cold hands and feet
  • Tachycardia

D. Management

Management of anemia depends on the specific deficiency or the specific subtype. Nonetheless, conventional management includes:

  1. Supplementation with Iron, Folate, or Vitamin B 12
  2. Use of corticosteroids in anemias where there is destruction of RBCs
  3. Blood Transfusions
  4. Erythropoietin supplementation
  5. Rest
  6. Treatment of the underlying condition that causes the anemia

E. Prevention

Prevention of anemia is possible. Ensuring that you eat a proper diet is one of the keys towards prevention of this disease. Supplement your diet with foods rich in iron, folate, vitamin B12 and vitamin C such as green leafy vegetables, dairy, eggs, organ meats, lentils, beans, meat, and others. If there is an underlying medical condition that may cause anemia, consult your doctor as to how to manage this condition.

Anemia Pathophysiology & Schematic Diagram

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