What is Aplastic Anemia?
Aplastic anemia is a rare and very serious disorder that results from the failure of the bone marrow to produce blood cells. In most cases the cause of this failure is not known. Aplastic anemia can occur at any age.
To understand aplastic anemia, you must understand the normal function of bone marrow. The central part of bone is filled with a red, spongy tissue called marrow. This marrow contains a small number of very important stem cells. These stem cells make both mature blood cells and new stem cells. These normal cells include red blood cells that carry oxygen, platelets that help to control bleeding by forming clots, and white blood cells that fight infection by attacking and destroying germs. The constant production of blood cells is needed because each cell has a limited life span after it leaves the bone marrow and enters the blood. Red cells live about 120 days, platelets about six days, and white blood cells only about four to 24 hours.
Normally, the bone marrow is an excellent factory. In aplastic anemia, normal blood cell production fails. As a result, symptoms of bleeding, infection and anemia develop. There is no common age that aplastic anemia occurs. Aplastic anemia affects males and females in equal numbers.
What are the symptoms of Aplastic Anemia?
The symptoms of aplastic anemia are related to the severity of the bone marrow failure. Symptoms of bleeding usually occur early. They include tiny red bruises about the size of a freckle, excessive bruising, nosebleeds and bleeding from the mucous membranes, such as the gums and the bladder.
As the white blood cell count falls, so does the child’s ability to fight infection. Even common germs can cause a serious infection if untreated could rapidly progress to death. Fever is usually the first sign of infection. Anemia, or low red blood cell count, is usually the last symptom to develop because the life span of the red blood cell is relatively long. Symptoms of anemia include pale appearance, fatigue, shortness of breath, and increased heart rate. Anemia may occur early if there is a lot of bleeding.
How is Aplastic Anemia diagnosed?
The diagnosis of aplastic anemia may be initially identified by a CBC. The diagnosis is suspected when all three cell lines (red cells, white cells and platelets) are very low. A bone marrow aspirate and biopsy may be needed to help confirm the diagnosis of aplastic anemia. Occasionally, leukemia can act like aplastic anemia. This happens when leukemia cells fill up the bone marrow.
This prevents the growth of normal bone marrow cells and can result in a decrease of all three types of blood cells in the blood. In aplastic anemia, the bone marrow shows a great reduction in the number of cells with a normal appearance of the few cells identified.
What is the cause of Aplastic Anemia?
The cause of aplastic anemia is often very hard to determine. In more than one half of the known cases of aplastic anemia, no cause is ever found. This is called idiopathic aplastic anemia. Some theories as to the cause of disease include defective stem cells, unregulated immune systems, excessive exposure to radiation or to certain chemicals, or certain infection may all lead to aplastic anemia.
What is the treatment for Aplastic Anemia?
A bone marrow transplant (BMT) is the treatment of choice in children with severe aplastic anemia. Unfortunately, BMTs in patients with aplastic anemia are usually successful only if there is an HLA identical match. An HLA identical match occurs when the markers on the patient’s cells are identical to the markers on the donor’s cells. Doctors look at between 6 and 10 different markers (depending on the lab at each hospital) on cells when they are looking for a match. Therefore, once the diagnosis of aplastic anemia is made, the patient’s parents and siblings have blood drawn to determine the HLA typing of each person. The HLA type classifies people according to markers on the surface of their white blood cells.
The survival rate for children with aplastic anemia who get a bone marrow transplant from an HLA identical, MLC compatible sibling is between 75-85%. Unfortunately, only about one-third of children diagnosed with aplastic anemia have an HLA identical sibling. Researchers are studying the use of unrelated matched donors. These donors are often found through the National Bone Marrow Registry. The search is a lengthy process and sometimes the chance of finding an unrelated donor is relatively small.
If your child has no donor available, treatment is often started with ATG or antithrombocyte globulin. This is given to suppress the patient’s immune system which may also be destroying the body. The immediate side-effects are due to serum sickness and include fever, rash, wheezing, joint pains, blood in the urine and, rarely a severe allergic reaction. These symptoms are treated with antihistamines and high dose steroids. It may take two to three months to see the effect of ATG on the production of bone marrow cells. During this time, supportive care with transfusions and antibiotics is very important. Slightly more than one half of patients treated with ATG are cured.
Cyclosporin A (CSA) is another drug given to suppress the immune system. Often ATG & CSA are given in combination.
Your child may need red blood cell and/or platelet transfusions. White blood cells are generally not transfused because of their very short lifespan. However, they may be used in rare cases of severe infection. Knowing the HLA typing of the donor providing the transfusion is essential.
Hand-washing helps to prevent the spread of infection to the patient. Infections can be caused from germs patients carry on and in their own body; and because the immune system is not functioning normally, the body cannot fight the germs. Prompt intravenous antibiotics need to be started at the first sign of infection, since life-threatening infections can develop quickly. Fever, pain, tenderness or bleeding may be the only signs of infection.
Without bone marrow transplantation about 50% of children with aplastic anemia survive. Research into the causes and treatment options continues.
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For additional information on this or any Health Topic, please call the Family Resource Center, 513-636-7606, or your pediatrician.
Written 11/05