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Aplastic anemia
Last reviewed: 23.04.2024
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Aplastic anemia is a composite group of diseases, the main symptom of which is depression of bone marrow hemopoiesis according to aspirate and bone marrow biopsy and peripheral pancytopenia (anemia of different severity, thrombocytopenia, leukogranulocytopenia and reticulocytopenia) in the absence of diagnostic signs of leukemia, myelodysplastic syndrome, myelofibrosis and tumor metastases . With aplastic anemia, there is a loss of all germs of hemopoiesis (erythroid, myeloid, megakaryocytic) and replacement of the hematopoietic bone marrow with fat tissue.
The meaning of the term "aplastic anemia" is the combination of a decrease in hemoglobin and erythrocyte in the peripheral blood with a devastated, inactive bone marrow. It is obvious that this term, introduced at the end of the XIX century. And reflecting only the external, the most vivid phenomenology of a group of fairly diverse diseases, is not accurate. Indeed, no less important sign of the acquired aplastic anemia is the destruction of granulo- and megakaryocyte sprouts. On the other hand, terms such as "hematopoiesis depressions" or "bone marrow deficiency syndromes" are either inaccurate in nature or are broader concepts. Thus, these groups include syndromes that have principal etiological and / or pathogenetic differences from aplastic anemia, for example, myelodysplastic syndromes or chronic lymphocytic leukemias from large granular lymphocytes.
It should be noted that in the hematological practice the term "aplastic anemia" is used only to designate acquired trilinear aplasia. Syndromes of monolinear cytopenia in combination with aplasia or reduction of the corresponding sprout in the bone marrow have other names.
Three-linear aplastic anemia was first described by Paul Ehrlich in 1888 in a pregnant woman who died from fulminant disease, manifested by severe anemia, fever and bleeding. Ehrlich emphasized the surprising inconsistency between anemia, leukopenia and devastated, devoid of erythroid and myeloid progenitor bone marrow. Actually, these 2 signs - pancytopenia and poor bone marrow - and currently serve as the main diagnostic criteria for aplastic anemia. The study of diseases, which are also accompanied by pancytopenia, but have nothing (or have little) in common with aplastic anemia, led to the addition of a number of the necessary criteria for the diagnosis of aplastic anemia with several other features: absence of liver and spleen enlargement, myelofibrosis, and clinical and morphological features myelodysplastic syndrome or acute leukemia.
Currently, the term "aplastic anemia" is generally accepted, which includes all forms or stages of hypo- and aplastic anemia, previously identified by various authors. The incidence in children is 6-10 cases per 1,000,000 children per year.
[Causes of aplastic anemia
The cause of development of aplastic anemia is still not fully understood. Exogenous and endogenous etiological factors of aplastic anemia development are distinguished. Exogenous factors are given a priority role in the development of the disease, such as physical effects, chemicals (primarily medicines), infectious agents (viruses, bacteria, fungi).
Pathogenesis of aplastic anemia
According to modern concepts based on numerous cultural, electron microscopic, histological, biochemical, enzymatic methods of investigation, three main mechanisms are important in the pathogenesis of aplastic anemia: direct damage to polypotent stem cells (PCN), changes in the microenvironment of the stem cell and, as a result, inhibition or disturbance its functions; immunopathological condition.
Symptoms
Retrospective studies found that the average interval from the effect of the etiological agent before the occurrence of pancytopenia is 6-8 weeks.
Symptoms of aplastic anemia are directly related to the degree of reduction of 3 important parameters of peripheral blood - hemoglobin, platelets and neutrophils. The vast majority of patients with aplastic anemias turn to the doctor for bleeding, and life-threatening bleeding as the first clinical manifestation of the disease is very rare.
Classification of aplastic anemia
Depending on whether there is an isolated oppression of the erythroid sprout or all germs, distinguish between partial and total forms of aplastic anemia. They are accompanied respectively by isolated anemia or pancytopenia. The following variants of the disease are distinguished.
Classification of aplastic anemia
Plan for examination of patients with aplastic anemia
- Clinical analysis of blood, with the determination of the number of reticulocytes and DC.
- Hematocrit.
- Blood type and Rh factor.
- Myelograms from 3 anatomically different points and trepanobiopsy, determination of colony-forming properties and cytogenetic analysis in hereditary variants of the disease.
- Immunological examination: determination of antibodies to erythrocytes, platelets, leukocytes, determination of immunoglobulins, typing according to the HLA system, RBTL.
What do need to examine?
How to examine?
Treatment of aplastic anemia
Bone marrow transplantation from a fully histocompatible donor is considered a therapy of choice for a primary diagnosed severe aplastic anemia and should be performed immediately, since this type of treatment is most effective in children.
The frequency of long-term survival in children who underwent bone marrow transplantation in the early stages of the disease from a fully HLA-compatible donor, according to the literature, is 65-90%. The most widespread was allogeneic bone marrow transplantation, which uses bone marrow from siblings, that is, from siblings with the greatest antigenic affinity for the recipient. If it is impossible to obtain bone marrow from snbling try to use bone marrow from other relatives or HLA-compatible unrelated donors. Unfortunately, only for 20-30% of patients you can find a suitable donor. Transplantation of incompletely compatible stem cells of donor cord blood is possible.
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