ANEMIA

PRERNA FOR IAS

ANEMIA

1. Anemia – Definition

Anemia is a condition in which the number of red blood cells (RBCs) or the level of hemoglobin (Hb) in the blood is lower than normal. Since hemoglobin carries oxygen from the lungs to body tissues, anemia reduces the blood’s oxygen-carrying capacity. As a result, the body receives less oxygen, causing symptoms such as fatigue, weakness, pale skin, dizziness, and shortness of breath. Anemia is not a disease itself but a sign of an underlying health problem. It may result from nutritional deficiencies, blood loss, bone marrow disorders, inherited conditions, or increased destruction of red blood cells.

2. Iron Deficiency Anemia

Iron Deficiency Anemia is the most common type of anemia worldwide and occurs due to insufficient iron, which is essential for hemoglobin synthesis. It produces microcytic, hypochromic red blood cells, meaning they are smaller and paler than normal. Common causes include poor dietary intake, chronic blood loss, pregnancy, and intestinal malabsorption. Symptoms include fatigue, weakness, pale skin, dizziness, brittle nails, and pica, a craving for non-food substances like clay or ice. Laboratory findings include low serum iron, low ferritin, increased total iron-binding capacity (TIBC), and reduced hemoglobin levels. Treatment involves iron supplementation and correcting the underlying cause.

3. Megaloblastic Anemia

Megaloblastic anemia develops due to a deficiency of Vitamin B₁₂ or folic acid, both of which are essential for DNA synthesis. The bone marrow produces unusually large, immature red blood cells called megaloblasts, resulting in macrocytic anemia. Patients experience fatigue, weakness, pale skin, and glossitis (inflamed tongue). Vitamin B₁₂ deficiency may also cause neurological symptoms such as numbness, tingling, poor balance, and memory problems. Laboratory findings include increased mean corpuscular volume (MCV), decreased serum Vitamin B₁₂ or folate levels, and hypersegmented neutrophils. Treatment consists of replacing the deficient vitamin and addressing the underlying cause.

4. Aplastic Anemia

Aplastic anemia is a rare but serious disorder in which the bone marrow fails to produce sufficient blood cells, including red blood cells, white blood cells, and platelets. Causes include certain medications, radiation exposure, toxic chemicals, viral infections, and autoimmune disorders. Patients develop pancytopenia, leading to fatigue, frequent infections, easy bruising, and excessive bleeding. Blood tests show low counts of all blood cells, while bone marrow examination reveals hypocellular marrow with reduced stem cells. Treatment may include blood transfusions, immunosuppressive therapy, antibiotics, and bone marrow transplantation, which offers the best chance of long-term cure in suitable patients.

5. Hemolytic Anemia

Hemolytic anemia occurs when red blood cells are destroyed faster than the bone marrow can replace them. The destruction may be inherited, such as sickle cell disease, or acquired due to autoimmune diseases, infections, drugs, or toxins. Symptoms include fatigue, pallor, jaundice, dark-colored urine, enlarged spleen (splenomegaly), and rapid heartbeat. Laboratory findings show increased reticulocyte count, elevated lactate dehydrogenase (LDH), increased indirect bilirubin, and decreased haptoglobin levels. Treatment depends on the cause and may include corticosteroids, immunosuppressants, blood transfusions, folic acid supplements, or removal of the spleen in selected cases.

6. Sickle Cell Anemia

Sickle Cell Anemia is an inherited autosomal recessive blood disorder caused by a mutation in the HBB gene on chromosome 11. This mutation produces abnormal hemoglobin called Hemoglobin S (HbS). Under low oxygen conditions, HbS polymerizes, causing red blood cells to become rigid and sickle-shaped. These abnormal cells break down easily, causing hemolytic anemia, and block small blood vessels, leading to painful vaso-occlusive crises. Patients experience anemia, pain episodes, jaundice, recurrent infections, delayed growth, and organ damage. Management includes hydroxyurea, blood transfusions, folic acid, antibiotics, and bone marrow transplantation in selected cases.

7. Thalassemia