Intravascular heamolysis occurs in: (A) Hereditory spherocytosis, (B) Antoimmune haemolytic anemia, (C) Paroxysmal nocturnal hemoglobinuria, (D) Thalassemia
Answer is C. Paroxysmal noctural hemoglobunuria (PNH) is the only hemolytic anemia caused by an acquired intrinsic defect in the cell membrane. It is associated with intravascular hemolysis. Rest all conditions causes extravascular heamolysis.