What causes Hemolytic anemia?

Hemolytic anemia occurs when red blood cells (RBCs) are destroyed faster than the bone marrow can replace them. Several factors can cause this:

Abnormal RBCs: Some inherited conditions, such as sickle cell anemia, thalassemia, and enzyme deficiencies, can cause RBCs to be abnormally shaped or function improperly, leading to their premature destruction.

Autoimmune disorders: In autoimmune hemolytic anemia, the immune system mistakenly attacks the body's own red blood cells, leading to their destruction. This can occur due to various conditions like autoimmune diseases (e.g., systemic lupus erythematosus), certain medications, and infections.

Mechanical damage: RBCs can be mechanically damaged when passing through abnormal heart valves (valvular heart disease), blood vessel abnormalities, or artificial devices (such as heart valves or blood pumps). This damage can cause the cells to rupture and be removed from circulation.

Infections: Some infections, such as malaria and babesiosis, directly invade and destroy RBCs. Additionally, certain bacterial infections can produce toxins that damage red cells, contributing to hemolysis.

Drugs and toxins: Certain medications (e.g., antimalarials, chemotherapy drugs, antibiotics), as well as exposure to toxins (like lead, arsenic, benzene, and snake venom), can cause oxidative damage to RBCs, leading to their breakdown.

Blood transfusions: In some cases, receiving incompatible blood during a transfusion can cause an immune response that destroys the transfused red cells, leading to hemolytic transfusion reactions.

Rare causes: Some rare conditions, such as paroxysmal nocturnal hemoglobinuria (PNH), can cause red cell destruction through complement activation. Additionally, certain metabolic disorders (e.g., glucose-6-phosphate dehydrogenase deficiency) can make RBCs more susceptible to damage in response to triggers like infection, certain drugs, or oxidative stress.