Hemolytic Anemias From Changes Outside Of The RBC
Hemolysis can also occur outside of the red blood cells (RBC). Whatever the process is that leads to destruction of RBC’s, eventually the spleen will filter out these damaged RBC’s leading to swelling of the spleen (splenomegaly) and anemia (a lowered RBC count in the blood). When more severe damage has occurred to the RBC’s the live will help the spleen in the task of removing the damaged RBC’s. This can lead to inflammation of the liver and in chronic cases even to cirrhosis of the liver.
There are several reason’s why a person would develop hemolytic anemia outside of the RBC.
Autoimmune hemolytic anemia
This is one of the causations. I am discussing this in detail under the link accessible under “Related Topics” below. Briefly, there can be cold agglutinins, which are antibodies produced by such diverse conditions like infections with mononucleosis, in a patient with mycoplasma pneumonia or in association with certain abnormalities in the lymphatic tissues. But there are also warm antibody hemolytic anemias that lupus or certain drugs like levodopa can produce. Levodopa is the drug of choice for treatment of Parkinson’s disease. There are many other drugs that can lead to these complexes with RBC’s. Antibodies directed against these complexes can lead to autoimmune hemolytic anemia.
Traumatic hemolytic anemia
This is another cause of hemolytic anemias from changes outside of the RBC. In this case a variety of different factors discussed in detail under this link can lead to schistocytes. The spleen and liver remove these damaged and fragmented RBC’s from the circulation.
Splenomegaly and Hypersplenism
Splenomegaly and hypersplenism are another reason why hemolytic anemias from changes outside of the RBC occur. There are a variety of causes for a large spleen to develop. These are outlined under this link. Briefly, Hodgkin’s disease and polycythemia vera can cause splenomegaly, but so can chronic infectious diseases like tuberculosis, malaria, syphilis and brucellosis. When the splenomegaly becomes chronic, hypersplenism sets in , which means that the chronically enlarged spleen is now so effective in removing RBC’s that this condition becomes a new entity and removal of the enlarged spleen may become part of the treatment plan. Needless to say that there must be close consultation between the hematologist and the surgeon.
1. The Merck Manual: Hemolytic anemia
2. Noble: Textbook of Primary Care Medicine, 3rd ed., Mosby Inc. 2001
3. Goldman: Cecil Medicine, 23rd ed., Saunders 2007: Chapter 162 – APPROACH TO THE ANEMIAS