Bone Marrow Transplantation

Bone Marrow Transplantation

Bone Marrow Transplantation operations are complex procedures employed for the treatment of severe medical conditions, once thought incurable. Transplantation is recommended for patients that are suffering from bone marrow deficiencies which occur as a result of sickle cell disease or thalassemia, or other disorders causing abnormalities in the process of red blood cell production; bone marrow deficiencies may also appear due to aggressive chemotherapy or radiation therapy in patients with certain forms of cancer (such as lymphoma or leukemia). Also, aplastic anemia may also cause bone marrow deficiencies.

Other affections which may be treated through Bone Marrow Transplantations are immunodeficiency disorders such as severe combined immunodeficiency syndrome and congenital neutropenia. This procedure may also be employed as a direct treatment for several types of cancer (myeloma, leukemia, lymphomas). Many of these disorders cause a malfunction of the stem cells in the bone marrow; these malfunctions may lead to the production of excessive numbers of immature, defective blood cells or abnormally low blood cell counts. These conditions allow the defective cells to interfere with the normal process of blood cell production and to accumulate in the bloodstream; in advanced stages of the disease, the defective cells invade other tissues, causing further disturbances in the normal functioning of the organism.

In order to treat these disorders through more conventional methods, extremely large doses of radiation or chemotherapy are required. However, these procedures also affect and destroy the normal bone marrow cells. Aggressive chemotherapeutic procedures used to treat certain types of cancer also cause the destruction of normal bone marrow cells. Bone Marrow Transplantation now offers the possibility to effectively treat these diseases through radiation and chemotherapy while at the same time allowing the replacement of the bone marrow after the treatment has completed.

At this time, the Bone Marrow Transplantation procedure does not yield 100% success rate. However, the patient’s chances at a healthy, normal life are dramatically increased. At the very least, this procedure gives the patients a prolonged period of time until the disease recurs and treatment must be started again.

Bone Marrow Transplantation Description

During Bone Marrow Transplantation, the patient’s bone marrow is replaced with the new healthy cells; this is accomplished by destroying the old, diseased cells and infusing the new cells into the patient’s bloodstream. If the transplant is successful, the healthy cells will migrate to the large bones and settle in the cavities, they will engraft and start to produce healthy blood cells.

Bone Marrow Transplantation operations where the patient receives new bone marrow from a donor are called allogeneic transplants, whereas if the marrow is received from an identical twin the transplant is syngeneic. Allogeneic transplants have the requirement that the new bone marrow must be as close as possible to the receiver’s genetic makeup – a perfect match is the ideal situation. In order to determine the compatibility between the donor and the receiver, special blood tests are performed; this is extremely important because if the two genetic makeups do not match, the new bone marrow will perceive the receiver’s entire organism as foreign material and will start attacking it. This condition is known as the GVHD – the graft versus host disease, and often results in the patient’s death. Another possibility is that the receiver’s immune system attacks the new bone marrow cells and destroys them, a condition known as graft rejection.

In some situations it is possible for the patient to be the donor as well as the receiver. Such Bone Marrow Transplantation operations are known as autologous procedures. This type of operations is possible in cases where the disease is already in remission or if the patient does not suffer from any condition affecting the bone marrow – for example breast or ovarian cancers, brain tumors, Hodgkin’s disease or non-Hodgkin’s lymphoma. In other situations, the bone marrow can be extracted from the patient and cleansed of any malignant cells before transplanting it back.

Bone Marrow Transplantation Related Medication

Bone Marrow Transplantation operations involve a high risk for the receiver. Around 10% of the cases result in the patient’s death, and this causes the treatment to be limited to patients whose chances of survival are already very low. Apart from the difficulties related to finding a suitable donor, the patient is also exposed to a number of side effects and complications.

Infection is a severe threat to the receiver, due to the fact that they must undergo myeloablation (the process through the patient’s bone marrow is destroyed). It may take weeks until the transplant is performed, and all this time the patient has severely low white blood cell counts which leaves them susceptible to infections, sepsis and septic shock. Prophylactic antibiotic therapies are performed; however the risk is still very high. The situation is worsened by the action of the immunosuppressive agents, which are administered continuously for at least 6 months after the transplantation has completed. Also, the receiver loses his or her acquired immunity and need to be vaccinated again once the immunosuppressive therapy is discontinued.

Another complication that may occur is hepatic veno-occlusive disease, characterized by hepatomegaly, fluid retention and high levels of bilirubin. This condition is associated with a high rate of mortality and while defibrotide and anticoagulants may be administered to control this affection, these medicines may increase the chances and severity of bleeding complications. Another drug which may be employed in the prevention of this disease is Ursodiol.

One of the most common affections that appear after Bone Marrow Transplantation operations is mucositis, characterized by mouth and throat lining damage. This is not a life threatening condition, however it causes great pain and renders the patient unable to eat or drink. Mucositis may be treated with pain suppression medication coupled with intravenous infusions administered to prevent malnutrition and dehydration.

Graft versus host disease is one of the most severe complications that may occur after a Bone Marrow Transplantation procedure. This affection occurs as the transplanted bone marrow cells recognize the host organism as a foreign object and attacks the tissues. Standard treatment for this condition involves administration of corticosteroid drugs, however the immunosuppressive effects may lead to the onset of life threatening infections.