Anemia

Anemia

Definition: Anemia is a condition characterized by a decrease in the number of red blood cells (RBCs) and hemoglobin (Hb) in the blood, leading to a reduced ability to carry oxygen to the body’s tissues.

Symptoms:

• Impaired oxygen transport: Due to reduced Hb, blood becomes less efficient in carrying oxygen to the tissues, causing symptoms such as fatigue, dizziness, and shortness of breath.

• Changes in RBC structure: Anemia can lead to changes in the size, shape, and color of RBCs.

• Manifestations of underlying disease: Anemia is often a sign of an underlying medical condition, such as blood loss, hematopoietic disorders, or hemolysis.

Mechanism: Anemia occurs due to an imbalance between RBC production and destruction.

Erythropoietin (EPO):

• Role: EPO is a hormone primarily produced in the kidneys, responsible for stimulating the bone marrow to produce RBCs.

• Mechanism: EPO binds to receptors on bone marrow stem cells, triggering their differentiation and maturation into red blood cells.

Classification:

• Blood loss anemia:

• Acute anemia: Occurs due to rapid blood loss, such as trauma, gastrointestinal bleeding.

• Chronic anemia: Occurs due to gradual blood loss, such as menorrhagia, hemorrhoids, hookworm infection.

• Hemolytic anemia: Occurs when RBCs are destroyed faster than normal.

• Intrinsic hemolytic anemia: Due to defects in the structure of RBCs, such as hereditary spherocytosis, G6PD deficiency, sickle cell disease, thalassemia.

• Extrinsic hemolytic anemia: Due to external factors such as anti-red blood cell antibodies, drugs, infections.

• Anemia due to decreased production: Occurs when the bone marrow does not produce enough RBCs.

• Deficiency of RBC production materials: Iron, vitamin B12, folic acid deficiency.

• Bone marrow diseases: Leukemia, aplastic anemia.

Characteristics of each type of anemia:

• Acute blood loss anemia:

• Symptoms: Significant blood loss, decreased blood pressure, rapid pulse, pale skin, dizziness, fatigue, even shock.

• RBC characteristics: Normocytic, normochromic (normal size and color).

• Recovery: Providing blood, fluid infusion, and iron and nutritional supplements help RBCs recover after 3-4 weeks.

• Chronic blood loss anemia:

• Symptoms: Fatigue, pale skin, flattened nails, prone to breakage, smooth tongue, loss of papillae.

• RBC characteristics: Hypochromic (pale color), microcytic (small size), poikilocytosis (irregular shape), anisocytosis (varied size).

• Mechanism: The body adapts to blood loss, leading to reduced RBC production, but with smaller size.

• Hemolytic anemia:

• Symptoms: Jaundice, yellow eyes, dark yellow urine.

• Characteristics: Free Hb in the blood, Hb in urine (hemoglobinuria), increased serum iron, increased free bilirubin, increased conjugated bilirubin, increased stercobilinogen, increased urobilinogen, increased reticulocytes.

• Mechanism: RBCs are destroyed faster than normal, releasing hemoglobin into the blood, causing the above symptoms.

• Hereditary spherocytosis: A disease caused by a defect in the red blood cell membrane, causing RBCs to be round and easily broken.

• G6PD deficiency: A disease caused by the deficiency of G6PD enzyme, making RBCs susceptible to oxidation and destruction, often triggered by exposure to oxidants like drugs and foods.

• Thalassemia: A genetic disease caused by defects in the globin chain of hemoglobin, leading to reduced RBC production and easy breakage.

• Iron deficiency anemia:

• Symptoms: Pale skin, pale mucous membranes, flattened nails, prone to breakage, smooth tongue, loss of papillae.

• RBC characteristics: Hypochromic, microcytic (small size).

• Causes: Chronic blood loss, inadequate iron intake, decreased iron absorption, impaired iron distribution.

Adaptive responses of the body in anemia:

• Respiratory system: Increased pulmonary ventilation, shortness of breath to enhance oxygen delivery to the body.

• Circulatory system: Increased heart rate, increased cardiac output, enlarged heart, chest pain, fatigue, weakness, increased blood volume mobilization, increased blood distribution to the skin, reduced Hb -> pale skin, mucous membranes.

• Central nervous system: Dizziness, lethargy, fainting.

• Increased tissue oxygen utilization: The body enhances its ability to use oxygen more effectively.

• Bone marrow increases RBC production: Bone marrow attempts to increase RBC production to compensate for the deficiency.

Note: This article provides general information about anemia. For accurate diagnosis and treatment, you should consult a doctor.