Aplastic anemia
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Editor-In-Chief: Aric Hall, M.D., Beth Israel Deaconess Medical Center, Boston, MA[1]
Overview
Historical Perspective
Classification
Pathophysiology
Causes
Differentiating Aplastic anemia from other Diseases
Epidemiology and Demographics
Risk Factors
Screening
Natural History, Complications, and Prognosis
Diagnosis
Diagnosis
The diagnosis can only be made on bone marrow examination. This will reveal a hypocellular bone marrow with fatty replacement of the normal hematopoetic precursors. The primary diagnostic dilemma is differentiating aplastic anemia from a hypocellular myelodysplastic syndrome. Before this procedure is undertaken, a patient will generally have had other blood tests to find diagnostic clues, including a full blood count, renal function and electrolytes, liver enzymes, thyroid function tests, vitamin B12 and folic acid levels.
Treatment
Treating aplastic anemia involves suppression of the immune system, an effect achieved by daily medicine intake, or, in more severe cases, a bone marrow transplant, a potential cure but a risky procedure. The transplanted bone marrow replaces the failing bone marrow cells with new ones from a matching donor. The pluripotent stem cells in the bone marrow reconstitute all three blood cell lines, giving the patient a new immune system, red blood cells, and platelets. However, besides the risk of graft failure, there is also a risk that the newly created white blood cells may attack the rest of the body ("graft-versus-host disease").
Medical therapy of aplastic anemia often includes a short course of anti-thymocyte globulin (ATG or anti-lymphocyte globulin) and several months of treatment with cyclosporin to modulate the immune system. Mild chemotherapy with agents such as cyclophosphamide and vincristine may also be effective. Antibodies therapy, such as ATG, targets T-cells, which are believed to attack the bone marrow. Steroids are generally ineffective.
In the past, before the above treatments became available, patients with low leukocyte counts were often confined to a sterile room or bubble (to reduce risk of infections), as in the famed case of Ted DeVita.
Prognosis
Untreated aplastic anemia is an illness that leads to rapid death, typically within six months. If the disease is diagnosed correctly and initial treatment is begun promptly, then the survival rate for the next five to ten years is substantially improved, and many patients live well beyond that length of time.
Occasionally, milder cases of the disease resolve on their own. Relapses of previously controlled disease are, however, much more common.
Well-matched bone marrow transplants from siblings have been successful in young, otherwise healthy people, with a long-term survival rate of 80%-90%. Most successful BMT recipients eventually reach a point where they consider themselves cured for all practical purposes, although they need to be compliant with follow-up care permanently.
Older people (who are generally too frail to undergo bone marrow transplants) and people who are unable to find a good bone marrow match have five year survival rate of up to 75%.
Follow-up
Regular full blood counts are required to determine whether the patient is still in a state of remission.
10-33% of all patients develop the rare disease paroxysmal nocturnal hemoglobinuria (PNH, anemia with thrombopenia and/or thrombosis), which has been explained as an escape mechanism by the bone marrow against destruction by the immune system. Flow cytometry testing is probably warranted in all PNH patients with recurrent aplasia.
See also
External links
- Aplastic Anemia & MDS International Foundation
- Mayo Clinic
- University of Texas
- Template:MedlinePlusEncylopedia -- Idiopathic aplastic anemia
- Template:MedlinePlusEncylopedia -- Secondary aplastic anemia
- The Aplastic Anaemia Trust
- Help for Aplastic Anemia sufferers
References
bn:অবর্ধক রক্তশূন্যতা de:Aplastische Anämie it:Anemia aplastica nl:Beenmergdepressie fi:Aplastinen anemia sv:Aplastisk anemi