Alterations that render red blood cells less flexible are most closely associated with which type of hemolysis?

• A. Intravascular hemolysis
• B. Extravascular hemolysis
• C. Autoimmune hemolytic anemia
• D. Microangiopathic hemolytic anemia

Answer: (B)

Decreased deformability of red blood cells leads to their preferential clearance by the spleen. When membranes or cytoskeletal changes make RBCs more rigid, they can’t squeeze through the narrow splenic cords as effectively. The spleen’s macrophages recognize these stiff, abnormal cells and remove them from circulation, resulting in destruction outside the vessels—extravascular hemolysis. In contrast, intravascular hemolysis happens when RBCs lyse within the blood vessels, often due to complement activation or mechanical rupture, and microangiopathic hemolysis involves fragmentation of RBCs in small vessels. Autoimmune hemolysis can cause extravascular destruction as well, but the specific link here is that rigid, less deformable cells are cleared by the spleen, making extravascular hemolysis the best fit.