Hemolytic anemias

  • What is a hemolytic anemia?

Normally the bone marrow produces three types of blood cells, red cells, white cells and platelets. The produced cells enter the blood and circulate for a certain period of time.

In case of red blood cells (RBCs) millions of red cells are produced every day and millions of others get destroyed. Normaly RBCs have a life span of 120 days in the blood. After that, they get destroyed mainly in an organ called spleen.

Some times for some reasons, the RBCs instead of circulating for 120 days may get destroyed prematurely, say for example within 30-40 days. This premature destruction of red blood cells cause hemolytic anemia.

  • How is it caused?

There are innumerable causes of hemolytic anemia.

In general, this can be due to inherited defects in red cells, which are present from birth. This can be due to defect in the red cell membrane or defects in Haemoglobin formation or defects in the red cell metabolism. Any of these defects will cause the RBCs to destroy prematurely.

Some of them may be due to acquired causes. For example some people develop, antibodies to red cell membranes, which cause premature destruction of RBCs.

  • What are the consequences?

Normally if the Red blood cell destruction is minimal, the bone marrow can compensate for it, by increased production. But, if the red cell destruction is moderate or severe, increased production in the bonemarrow cannot compensate for the increased destruction of RBCs.

This produces anemia.

In addition, when RBCs are destroyed in increased numbers, there is increased release of hemoglobin(Hb) from the RBCs. Normally this Hb is converted to bilirubin and excreted in the liver. The liver has limited capacity of handling the bilirubin. If there is excess production due to increased destruction of RBCs, the liver cannot cope up with that, resulting in increased bilirubin which spills over into the blood, producing jaundice.

This jaundice, is different from the jaundice produced due to liver diseases. Here the jaundice, is due to increased production of bilirubin (these are forms of indirect bilirubin).  The jaundice in these patients will not produce loss of appetite or liver damage. So, the jaundice need not be treated. Some people with moderate hemolytic anemia may have persistent jaundice. In these people, the hemolytic anemia has to be controlled to reduce the jaundice.

Sometimes, due to increased bilirubin production these people can form gall stones.

In severe cases, increased marrow production to compensate destruction can cause expansion of marrow space, which can cause bony deformity and fractures.

  • How is hemolytic anemia managed?

Management is entirely dependant on the cause of hemolytic anemia.

In congential hemolytic anemias, repeated packed cell transfusions may be necessary.

In acquired hemolytic anemias, esp. in autoimmune hemolytic anemia, which is due to destruction of RBCs due to antibodies, treatment is immunosuppression to prevent the antibodies from destroying the red cells. Blood transfusion can be harmful in auto immune hemolytic anemias, as they may destroy the transfused blood as well, and may become more jaundiced.

There are various therapeutic options available depending on the cause of hemolytic anemia, such as removal of spleen (which is the major site of destruction of RBCs). In some cases, this can be due to toxins, drugs or even due to mechanical such as valvular obstruction in the heart. Treatment should be specific depending on the  cause.

Some of the congenital hemolytic anemias such as thalassemias may be benefited by allogenic stem cell transplantation.

  • How is auto immune hemolytic anemia treated?

Usually these anemias respond to immuno suppressive therapy with steroids. However, in many patients the disease may recur later after the steroids are stopped or while reducing the dose of steroids. These patients may need additional immunosuppression. These patients are continued with immuno suppression for a longer time to keep the disease under control.

  • What is the natural course of auto immune hemolytic anemia?

In some patients it will be an one time event. In many patients, they have to take some immunosuppressive drugs for a much longer time to keep the disease under control. (To find out which immunosuppressive durg best suits a patient may be a longer exercise sometimes). 

In few patients the disease remains quiescent for a long time, (for years) and gets exacerbated at times (during viral infections, pregnancy etc)

  • What precautions should I have to take?

Two things are important to remember.

As the disease may come back or exacerbated at any time, you should know to identify it much earlier.

In auto immune hemolytic anemia, sudden onset palpitations, vomiting or unexplained tiredness are the warning signs.

Second thing, if you are on treatment esp immuno suppressive medications, during  any infections such as fever, cough, diarrohea etc, you have to get immediate and appropriate antibiotics. Contact your family Physcician immediately.

Department of Hemato oncology,

Amended on Dec 14th, 2014 @VNCC, GKNM by Dr Suthanthira kannan,

Amended on 2nd Nov, 2016 @ Coimbatore Kidney centre by Dr Suthanthira Kannan

 
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