What Happens in Thalassemia Major?
Other Names for thalassemia major are:
How does thalassemia major first show itself?
During pregnancy the inherited thalassemia major does not affect the fetus. This is because the fetus has a special sort of hemoglobin, called "fetal hemoglobin" (HbF for short). Children and adults have a different hemoglobin called "adult hemoglobin" (HbA for shot). When a baby is born, most of its hemoglobin is still the fetal kind, but during the first 6 months of life it is gradually replaced with adult hemoglobin. The problem with thalassemia, is that the child cannot make adult hemoglobin. Therefore children with thalassemia major are well at birth, but usually become ill before they are 18 months old. They usually become quite anemic (their Hb level is usually less than 8 g/dl). So they become pale, do not grow as well as they should, and often have a big spleen.
The number of months that can pass before a thalassemic child becomes ill, can differ quite a lot from case to case. This is because thalassemia can be caused by several different defects in the hemoglobin genes. Some cause a complete absence of adult hemoglobin. While others allow a small amount of adult hemoglobin to be made. We call the first kind beta-zero thalassemia (b0-thalassemia for short). It is usually a very severe thalassemia, so the anemia begins early, at about 6-9 months of age. We call the second type beta-plus thalassemia, (b+-thalassemia for short). It is a little less severe. So affected children may stay well for a little longer. However, nearly all children with b-thalassemia major of any type become ill before 2 years of age, and need blood transfusions.
How do the tissues of a child with thalassemia manage to breathe, if there is no adult hemoglobin?
The child's body reacts to the shortage of adult hemoglobin by making some fetal hemoglobin, so most of the hemoglobin in your own blood is HbF. But your body is programmed to make fetal hemoglobin only in the fetus. It can only make a very small amount later on - not nearly enough to keep a child alive for long.
What happens if thalassemia major is not treated?
The anemia gets worse, the child stops growing altogether, and the spleen goes on getting bigger, so the tummy gets very big. the bone marrow, the tissue that forms the red blood cells, expands inside the bones, trying to make more and more red cells. But its efforts are useless. The red cells it makes do not contain enough hemoglobin, and simply die without ever getting of the bone marrow. However, the marrow's efforts to expand make the bones weak and alters their shape. The cheek bones and the bones of the forehead begin to bulge and the child's face gets a characteristics look, so that people can see from a distance that something is wrong. As time passes, the spleen, whose normal job is to destroy old red blood cells in the circulation, begins to destroy young red blood cells too, and finally also the white blood cells and the platelets. So in the end, the spleen makes the child's illness worse.
How do we treat thalassemia major?
Two different treatments are available at present, traditional treatment, and Bone-marrow Transplantation, which we describe in Chapter 4 of this Section. Here we will describe the traditional treatment. It consists of (1) Blood Transfusion, sometimes (2) Removing the Spleen, and (3) Desferal Treatment.
1. Blood Transufion
To be precise, the treatment you need is not blood transfusion, but transfusion of red blood cells. You are only short of red blood cells, you make the other parts of the blood quite normally.
There are three reasons for blood transfusions.
(a) To correct your anemia. and make sure that your tissues get a normal amount of oxygen. This allows you to live and grow normally.
(b) To let your bone marrow rest, so that your bones can develop normally and you face looks normal.
(c) To slow down or prevent any increase in the size of your spleen, and to prevent hypersplenism.
When the spleen becomes too active and starts to destroy the red blood cell, transfusions become less and less effective. Then it may become necessary for a surgeon to take the spleen out. This operation is called "Splenectomy".
3. Desferal Treatment
Every ml1 of red cells transfused brings 1mg2 of iron into the body. This iron can't be taken out of the blood because it is part of the hemoglobin, which is what your body needs. On its own, your body can only get rid of a tiny amount of iron, so if you have transufusions regularly, iron gradually accumulates in your body. It is stored in certain organs, especially the liver, the heart, and the "endocrine" glands (Figure 7). The iron behaves like a foreign body, and in the end would damage the organs where it is deposited. Fortunately, there are drugs that can pick up the iron, and carry it out of your body in your urine and feces. The only one that is used regularly at present is desferrioxamine, which is also called "Desferal". If you se Desferal regularly, you can keep the amount of iron in your body down to a safe level.
1ml stands for milliliter, one thousandth of a liter. You can see how much it is from the syringe you use for your Desferal infusions.
2One mg stands for one thousandth of a gram. Since one gram is one thousandth of a kilogram, you can see that one milligram is one millionth of a kilogram! It is not very much, but it adds up with time.
What happens when thalassemia is treated correctly?
For a well-treated patient thalassemia is quite different from the untreated disease. There is no anemia, growth is normal, and the face and the bones look nonmoral. However, there can be complications because of stored iron, or because of infections passed on in transfused blood. It is possible for viruses to get into your body with the blood and to make you ill.
In Particular, it is possible to get hepatitis, which is an infection of the liver, this way. It is also possible for the AIDS virus to be transmitted by transfusions, but this is very remote possibility, because all blood donors are first tested for AIDS. People who are found to be carriers, or who have been infected with the AIDS virus in the past are not allowed to give blood.