ANEMIA, APLASTIC

Aplastic anemia is failure of the bone marrow to produce blood cells. It results in decrease in all types of blood cells: red blood cells, white blood cells, and platelets.

The cause of most cases (65%) of aplastic anemia is unknown. The incidence averages five to ten new cases per million persons per year. Exposure to chemicals such as benzene, insecticides (DDT), and explosives (TNT) is associated with some cases of the disease. Ionizing radiation also may cause aplastic anemia. Several medications, such as chloramphenicol (an antibiotic) and gold salts (therapy for rheumatoid arthritis), and some viral infections, such as hepatitis, can lead to the development of aplastic anemia. An immune system defect may cause suppression of bone marrow production.

A patient with aplastic anemia has signs of low blood counts. Evaluation of a blood smear and bone marrow test is necessary to make the diagnosis. The only curative treatment is allogeneic bone marrow transplantation. Several medications can produce remissions of the disease, but the remissions are temporary.

Severe aplastic anemia is a life-threatening disease. A low platelet count leads to bleeding and bruising and a low red blood cell count leads to anemia. A low white blood cell count predisposes the patient to infections.

Anemia can manifest itself as weakness, fatigue, and decreased tolerance of exercise. It can cause chest pain, dizziness, and shortness of breath. Lowering of the white blood cell count (leukopenia) decreases resistance to infection. Patients have recurrent infections, such as pneumonia, sinusitis, and skin infections. A low platelet count can cause prolonged bleeding from the vagina or nose, bleeding into internal organs, and easy, frequently spontaneous bruising.

Rapid diagnosis and initiation of therapy are necessary. Bone marrow transplantation from a family member or sometimes a matched, unrelated donor can bring a cure. Bone marrow transplantation can be performed, however, only on young patients. Only one fourth to one third of patients with aplastic anemia can undergo transplantation. For young patients with a suitable related donor, bone marrow transplantation is the treatment of choice. A compatible unrelated donor may be found through the National Marrow Donor Program and International Bone Marrow Registry. Blood transfusions should be limited before transplantation.

Bone marrow transplantation involves high doses of chemotherapy and infusion of bone marrow cells from a donor followed by a long course of immunosuppressive medications. A combination of immunosuppressive medications, such as cyclosporine, antilymphocyte globulin, and prednisone, produces remissions for as many as 70% of patients who cannot undergo a transplant. Treatment with immunosuppressive agents should be carefully monitored. The use of male hormones (androgens) can lead to improvement of symptoms for some patients. Supportive care with red blood cell and platelet transfusions is essential for all patients.

Allogeneic bone marrow transplantation is an intensive and toxic treatment. The procedure carries risk for infection and toxic effects of chemotherapy on the liver, lungs, and brain. These effects can be fatal for a small proportion of patients. Prolonged use of immunosuppressive drugs decreases resistance to some types of infections. Steroids, such as prednisone, can increase blood glucose level, elevate blood pressure, and cause stomach distress, loss of calcium and other salts, fluid retention, and weight gain. Infusion of antilymphocyte globulin can produce serum sickness. Androgenic hormones can cause liver damage, menstrual irregularities, and unwanted hair growth.

The bone marrow cells of the donor can attack the body and produce a serious complication called graft-versus-host disease. A skin rash, diarrhea, and liver dysfunction can develop. Continuous use of immunosuppression can prevent and manage graft-versus-host disease. Failure of the transplanted marrow to grow and function (graft failure) is another complication of bone marrow transplantation. Acute leukemia (myelodysplastic syndrome) can develop years after transplantation, but this is rare. However, among some patients acute leukemia may develop even without treatment.

Medications that protect the stomach may be necessary for patients who take steroids. Specific prophylactic antibiotics are administered. Frequent blood tests are used to monitor blood glucose, electrolytes, blood counts, and liver function tests.

• Take your medications as prescribed.
• Report for laboratory tests as directed.
• If you have a low white blood cell count, eat a special protective diet as recommended to limit bacterial contamination.
• Use Medic Alert identification.
• Have revaccination if you undergo bone marrow transplantation.

• Avoid crowds and contacts with people with obvious infections.
• Do not take aspirin and aspirin-like medications; they can increase the bleeding.
• Inform household members that they should not be vaccinated with live vaccines, such as live polio vaccine.
• Avoid eating fresh leafy vegetables, fruit, cheese, and yogurt.
• Limit interactive sports and strenuous exercise.

• If you have a fever, bleeding, chest pain, or dizziness. Prompt treatment is necessary.

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