Question

Intravascular hemolysis occurs in:

• A. Hereditary spherocytosis
• B. Autoimmune haemolytic anemia
• C. Paroxysmal nocturnal hemoglobinuria
• D. Thalassemia

Hint:

Remember — PNH = intravascular hemolysis with hemoglobinuria (dark urine in the morning).

Answer 1

The Correct Option is C

Intravascular hemolysis refers to the destruction of red blood cells within the blood vessels, releasing hemoglobin directly into the plasma.
Paroxysmal nocturnal hemoglobinuria (PNH) is a classic condition causing intravascular hemolysis due to a defect in the red cell membrane which makes cells susceptible to complement-mediated lysis.
Hereditary spherocytosis and autoimmune hemolytic anemia usually cause extravascular hemolysis where RBCs are destroyed primarily in the spleen.
Thalassemia also primarily involves extravascular hemolysis and ineffective erythropoiesis within the bone marrow.
Therefore, intravascular hemolysis is characteristic of PNH.