Hemolytic anemia

Hemolytic anemia is anemia due to hemolysis, the abnormal breakdown of red blood cells either in the blood vessels (intravascular hemolysis) or elsewhere in the body (extravascular). It has numerous possible causes, ranging from relatively harmless to life-threatening. The general classification of hemolytic anemia is either acquired or inherited. Treatment depends on the cause and nature of the breakdown.

In a healthy person, a red blood cell survives 90 to 120 days (on average) in the circulation, so about 1% of human red blood cells break down each day. The spleen (part of the reticulo-endothelial system) is the main organ which removes old and damaged RBCs from the circulation. In health the break down and removal of RBCs from the circulation is matched by the production of new RBCs in the bone marrow.

When the rate of breakdown increases, the body compensates by producing more RBCs, but if compensation is inadequate clinical problems can appear. Breakdown of RBCs can exceed the rate that the body can make RBCs and so anemia can develop. The breakdown products of hemoglobin will accumulate in the blood causing jaundice and be excreted in the urine causing the urine to become dark brown in colour.