Aplastic anemia is a type of bone marrow failure. The disease is rare but extremely serious. It is a condition in which the body stops making new blood cells. The disease is commonly found amongst the lower age bracket, specifically amongst late teens and early 20s, but it can occur later on in life, too, especially amongst the elderly.
The condition revolves around the failings of the bone marrow, which is a spongy tissue inside the bones, responsible for making white blood cells, red blood cells, and platelets. This trifecta of cells has a crucial role to play in the workings of the human body, with the white blood cells fighting infection, the red blood cells supplying oxygen and nourishment to other organs and tissues around the body, and the platelets clotting blood.
When the old blood cells die naturally, they are replenished by new blood cells formed in the boner marrow. In aplastic anemia, the bone marrow fails to produce new cells to replace the old ones, making the body prone to uncontrolled bleeding and infection. Sometimes, the bone marrow stops making just one type of blood cells, but more often than not, the body becomes low on all three of the blood cells.
There are two different types of aplastic anemia. It can be acquired or inherited, with the former being a more common occurrence. Inherited forms are caused by gene defects and are common in younger children and young adults. Inherited aplastic anemia creates higher chances of developing leukemia and other types of cancers. This form usually comes to the fore in the first decade of life.
On the other hand, acquired aplastic anemia is more commonly found in adults. It is believed by researchers that something triggers problems in the immune system. Commonly, it is believed to result from an attack mediated by the immune system at the hematopoietic progenitor cells, which are stem cells that turn into different types of blood cells. The immune system’s white blood cells interpret them as invaders and attack the hematopoietic stem cells leading to cell death.
It is believed that something external triggers the problems; the possible culprits include certain medications, toxic chemicals, radiation, or chemotherapy treatment for cancer or viruses like Epstein-Barr or HIV. In most cases, the cause of the disease can not be distinguished. This is why the disease is also called idiopathic aplastic anemia in some cases.
Moreover, it has been discovered that most of the severe cases of aplastic anemia are autoimmune disorders in which the body’s immune system mistakenly targets its organs and cells. Researchers argue that abnormal immune cells or autoreactive cells, known as lymphocytes, restrict blood cell production and the further division of cells.
While aplastic anemia is not classified as cancer, the treatment used for treating the disease follows courses and therapies similar to blood-forming cancers like lymphomas and leukemias.
Patients with aplastic anemia usually experience an extremely low quantity of each of three blood cells found in the body. This is the first sign that points to the likelihood of the disease. Commonly, people are low on all three blood cells, but each blood cell has a different symptom.
Symptoms of low red blood cell count are tiredness, dizziness, pale skin, headaches, shortness of breath, chest pain, and irregular heartbeat. Low white blood cell symptoms include infection. Symptoms of a low platelet count are nosebleeds, easy bruising, and bleeding. In light of any of these symptoms, a complete blood count test may be ordered. In addition, the doctor may order a biopsy of the bone marrow as well.
Patients may also be identified early through abnormalities caught via routine laboratory testing, but they usually have no symptoms. Overall, the most common symptoms are fatigue, weakness, recurring infections, the appearance of small red dots under the skin and headaches,
Aplastic anemia is a serious disease that needs immediate medical attention. Diagnosing the disease is a multi-step process. Physicians need to examine the blood and the bone marrow under a microscope. In order to do this, they order blood and laboratory tests as well as a bone marrow biopsy and aspiration.
For a bone marrow biopsy, a sample of bone marrow is removed from the hip bone with a special needle while the patient is under anesthesia. The doctor checks the overall blood count, which includes white cells known as neutrophils, the platelets or clotting cells, and the red blood cells, which are also called reticulocytes.
Additionally, the physician may also study kidney function and other tests associated with diagnosing aplastic anemia. HLA-typing, which is a laboratory blood test, is also performed to make sure that the patient will receive immune system compatible blood and marrow products over the course of their treatment.
The classification of aplastic anemia depends on the composition of your blood cell count in the blood tests and the bone marrow biopsy. There are three subgroups. The disease is classified as moderate aplastic anomia, also written as MAA or nSAA, severe aplastic anemia or SAA, and very severe aplastic anemia, also written as vSAA.
Severe aplastic anemia and very severe aplastic anemia are targeted and treated via aggressive treatment by doctors, while moderate aplastic anemia can simply be observed in a handful of situations.
How the disease is treated depends on its severity. Patients with severe aplastic anemia must be subject to immune system suppressing therapy or stem cell transplants. There is no established standard of care for moderate aplastic anemia.
Severe aplastic anemia patients younger than 40 years are usually treated with a bone marrow transplant with a blood-matched sibling. Those over 40 or without blood-matched siblings go down the drug therapy route. The various types of drug treatments are discussed in further detail below.
Platelet transfusions reduce the high probability of fatal hemorrhages for the patients. The transfusion of red blood cells aids in combating shortness of breath, weakness, and fatigue as experienced by patients. The process thus serves to ground and stabilize patients with severe blood cell deficiencies.
However, it’s extremely rare for patients to be set on the road to long-term recovery with blood transfusion alone. In general, people do not experience side effects from the transfusion, but possible side effects are infection, allergic reactions or fever,
A successful bone marrow transplant is a long-term cure for patients with severe aplastic anemia. There are few reported incidents of relapse. Nevertheless, bone marrow transplants are a form of aggressive and intensive therapy. They are also prone to serious immune complications as well as the growth of infections – which tend to be common.
There are some other side effects of bone marrow transplantation, but these are non-life-threatening. These effects include sterility and temporary hair loss in patients. The best-suited age bracket for bone marrow transplantation are patients under the age of 40.
The cure rates decline significantly for people beyond that age bracket, and doctors must turn to alternative treatment routes for such patients. Furthermore, bone marrow transplants from donors who are unrelated or mismatched, also known as alternative donors, are very rare.
They are usually reserved as a last resort for patients with severe or very severe aplastic anemia, provided they have not responded well to immunosuppressive drug therapy first.
Medical therapy for aplastic anemia involves immunosuppressive drug therapy with anti-thymocyte globulin, also known as ATG and cyclosporine. Drug therapy is not a cure in itself for aplastic anemia, but it does partially restore blood cell reproduction for some time.
Unfortunately, 50 percent of the patients relapse or end up developing other types of blood-forming malignancies and disorders. Sometimes, medical therapy is also administered before a bone marrow transplant.
There are a few side effects to medical therapy, and these include issues related to the kidneys, high blood pressure, and fever. In recent years, however, eltrombopag, a new drug, has been approved for severe cases of aplastic anemia. However, it must be noted that the drug has some limitations.
There is only a 20% response rate. Moreover, the likelihood of relapse remains high. Physicians usually turn to eltrombopag as an option for patients for whom a bone marrow or a stem cell transplantation is not an option.
Iron overload often becomes an issue after nearly twenty blood transfusions. Iron levels between 1000 and 2000 are deemed high, and in these cases, treatment is deemed essential. To treat iron overload, your doctor may prescribe an iron chelator, which removes the excess iron in your body.
Currently, there are two iron chelators approved for use in the U.S by the Food and Drug Administration– deferasirox, which is taken as a tablet dissolved in water, and deferoxamine which is administered by slow infusion in the vein via a portable pump. There are other drugs such as deferiprone, an oral iron chelator, which have been developed for use in Europe and other parts of the world.
There are two different types of growth factors used for treatment. The red blood cell growth factor is called EPO or erythropoietin. This is a hormone that is naturally produced by the body in the liver. There are man-made forms of erythropoietin that come in brand names like Epogen and Procrit. There are other options available as well – a hormone similar to EPO and Darbepoetin comes in a brand-name packaging called Aranesp.
On the other hand, there are some white blood cell growth factors as well. These are used in some rare cases. White blood cell growth factors include G-CSF, or granulocyte colony-stimulating factor, which is sold under brand names Neupogen and Filgrastim. A similar white cell growth factor known as a granulocyte-macrophage colony-stimulating factor or GM-CSF is sold by the name Lueking and Sargramostim.
Since fungal and bacterial infections are a common cause of death in patients that have a severe case of aplastic anemia, patients may also need routine therapy with antibiotics to treat them. In addition to antibiotics, antifungal agents and antiviral agents may also be used.
Moreover, a central venous catheter is also helpful for patients with aplastic anemia who need medication and blood transfusions on a fairly regular basis. However, it must be noted that some of these medicines have risks and side effects. Therefore, the doctor and the patient must decide whether the perceived benefits are higher than the risks.
There are some general guidelines issued to people who have been living with aplastic anemia.
Aplastic anemia is a rare disease. There are several factors in the external and internal environment that can increase the risk associated with it.
There are two known rare disorders that have been linked to aplastic anemia. Sometimes, people with aplastic anemia have another rare disorder known as paroxysmal nocturnal hemoglobinuria. In this disorder, red blood cells break down too soon. Thus, this condition can either lead to the development of aplastic anemia, or aplastic anemia can lead to paroxysmal nocturnal hemoglobinuria.
On the other hand, Fanconi’s anemia is a disease that is inherited, and it leads to the development of aplastic anemia. Children that are born with Fanconi’s anemia are usually smaller than an average healthy baby and often have birth defects like underdeveloped body parts. The disease is diagnosed after a series of blood tests.
Sarwat Makkani, MD
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Sameer Baig, MD
Yanelquis Torres, MD
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