Leukemia
The content of the article:
- Leukemia Causes
-
Forms
- Acute leukemia
- Chronic leukemia
- Stages
- Leukemia symptoms
- Diagnostics
- Leukemia treatment
- Potential consequences and complications
- Forecast
- Prevention
Leukemia is a malignant disease of the hematopoietic system. Synonyms - leukemia, blood cancer, leukemia.
It is caused by damage to the DNA of a hematopoietic cell. As a result of a genetic defect (mutation) in the cells of the bone marrow, specialized cells of the leukocyte lineage cease to mature completely, without developing into mature leukocytes. Abnormal, immature cells begin to divide rapidly and uncontrollably, spreading throughout the body in the form of leukemic infiltrates. The high potential of leukemic cell division, the release of a growth stimulator of tumor cells and factors inhibiting the process of normal hematopoiesis, contributes to the displacement of populations of normal leukocytes, a deficiency of healthy leukocytes, erythrocytes and platelets.
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The proliferation of leukemic cells in organs and tissues leads to severe anemia, severe dystrophic changes in the parenchymal organs, infectious complications, and hemorrhagic syndrome.
Acute leukemia is one of the most common forms of cancer, which occurs in people of any age. Leukemia in children is one of the most common types of oncopathology. The peak incidence occurs in children (3-4 years) and elderly (60-70 years) age. Men get sick more often than women.
Leukemia Causes
The causes of leukemia are not fully understood. Many factors can provoke a mutation in the cells of the hematopoietic system:
- hereditary factor - if one of the family members suffered from leukemia, the risk of its occurrence in loved ones increases;
- electromagnetic, radioactive, ionizing radiation;
- diseases associated with genetic disorders (Down syndrome, Fanconi anemia);
- viral infections (human T-lymphotropic viruses, Epstein-Barr virus);
- a history of diseases of the hematopoietic system (hemoblastosis) - refractory forms of anemia, myelodysplastic syndrome, paroxysmal nocturnal hemoglobinuria;
- long-term exposure to a number of toxic substances - chemical mutagens (formaldehyde, benzene, dibenzanthracene, benzpyrene);
- the effect of drugs used in chemotherapeutic treatment of other forms of cancer (cytostatics).
Forms
When classifying leukemias, the nature of chromosomal abnormalities, morphological differences, the ability of cells to secrete a certain immunoglobulin, the place of predominant cell proliferation, and immunological markers of the surface of tumor elements are taken into account.
All forms of leukemia are characterized by the replacement of normal tissue by pathological tumor tissue; the form of leukemia depends on which cell is the morphological substrate of the tumor.
According to the degree of differentiation (maturity) of tumor blood cells, two main forms of leukemia are distinguished:
- sharp;
- chronic.
Acute leukemia
The substrate of acute leukemia is formed by young blast cell forms. The classification of forms of acute leukemia is based on morphological (degree of cell maturity, changes in the shape of the nucleus and cytoplasm) and cytochemical characteristics of tumor cells. Various forms of acute leukemia are designated by the name of normal homologous bone marrow progenitors (lymphoblasts, erythroblasts, myeloblasts, etc.).
In this regard, acute leukemias are divided into the following types:
- lymphoblastic - the tumor develops from the precursor cells of lymphopoiesis;
- myeloblastic - the substrate of the tumor is the progenitor cells of myelopoiesis.
Each of the groups of acute leukemia is heterogeneous and includes different forms of the disease.
In the group of acute lymphoblastic leukemias, several forms of the disease have been identified by immunological markers and response to therapy:
- pre-B-form;
- B-form;
- pre-T-form;
- T-shape.
Myeloid leukemias are classified into the following types:
- erythromyeloblastic;
- monoblastic (myelomonoblastic);
- megakaryoblastic.
An undifferentiated form of leukemia is also diagnosed, in which a blood stem cell, which has become a tumor substrate, does not show signs of differentiation.
The acute form of leukemia often occurs with leukocytosis, but may be accompanied by leukopenia. The acute form of leukemia is characterized by leukemic failure (hiatus leucemicus) - young and mature forms of cells are presented in the leukocyte formula in the absence of transitional maturing forms.
Chronic leukemia
The substrate of chronic leukemia is composed of mature and maturing cells. The names of the forms of chronic leukemia are given according to the names of those cells that characterize tumor proliferation. Chronic leukemias are divided into the following types:
- leukemia of myelocytic origin - chronic myeloid leukemia, erythromyeloid leukemia, erythremia, polycythemia vera;
- leukemia of lymphocytic origin - chronic lymphocytic leukemia, skin lymphomatosis (Sesari's disease), paraproteinemic leukemia;
- leukemia of monocytic origin - chronic monocytic leukemia, histiocytosis.
In the chronic course of the disease, leukocytosis is observed, blast forms in the peripheral blood appear only with an exacerbation of the disease. Usually chronic leukemia remains for a long time at the stage of a monoclonal benign tumor.
Depending on the number of leukocytes in the peripheral blood, leukemias are divided into:
- leukemic;
- subleukemic;
- aleukemic;
- leukopenic.
Stages
With differentiated acute leukemias, the process proceeds in stages and goes through three stages.
- Initial - the symptoms are expressed in an insignificant degree, often the initial stage passes by the patient's attention. Occasionally, leukemia is detected on a random blood test.
- The stage of extensive manifestations, with clear clinical and hematological signs of the disease.
- Terminal - lack of effect from cytostatic therapy, pronounced suppression of normal hematopoiesis, ulcerative necrotic processes.
Remission in acute leukemia may be complete or incomplete. Relapses are possible, each subsequent relapse is prognostically more dangerous than the previous one.
Chronic leukemias are characterized by a more benign and prolonged course, periods of remission and exacerbations. There are three stages of chronic leukemia.
- The chronic stage is characterized by a gradually increasing leukocytosis, an increase in the overproduction of granulocytes, a tendency to thrombocytosis. The disease at this stage, as a rule, is asymptomatic or manifests itself as slightly pronounced signs of hypermetabolism, anemic syndrome.
- The stage of acceleration is a change in the blood picture, reflecting a decrease in sensitivity to ongoing and previously effective therapy. Most patients do not have new characteristic clinical symptoms or they are indistinctly expressed.
- Blast crisis stage (acute stage) - a sharp decrease in the level of erythrocytes, platelets and granulocytes, which leads to the appearance of internal bleeding, ulcerative necrotic complications, the development of sepsis.
With undifferentiated and poorly differentiated forms of leukemia, there is no staging of the pathological process.
Leukemia symptoms
Symptoms of acute leukemia are caused by tumor hyperplasia and infiltration of the bone marrow and other organs and tissues in the body. The first manifestations of the disease are general in nature: malaise, fever, weakness, joint pain, loss of appetite, sweating, the appearance of small bruises or small punctate hemorrhages on the skin and visible mucous membranes (petechiae and ecchymosis). Sometimes the disease begins under the guise of tonsillitis or ARVI.
In the extended period, the symptoms are more pronounced; in the clinical picture of the disease of this period, several clinical syndromes can be distinguished, depending on the localization of the lesions and signs of suppression of normal hematopoiesis:
- hyperplastic, or lymphoproliferative syndrome - manifests itself in an increase in lymph nodes (cervical, axillary, inguinal), liver, spleen, tonsils, swelling of the salivary glands, the appearance of skin lesions, meninges, kidneys, myocardium and lungs;
- hemorrhagic syndrome - hemorrhages in the skin, mucous and serous membranes, internal organs, from single or rare to extensive hemorrhages and profuse bleeding (gingival, nasal, uterine, renal, gastrointestinal, hemorrhages on the skin and mucous membranes);
- anemic syndrome - caused by the suppression of normal hematopoiesis by a malignant clone of cells, manifested by signs of circulatory-hypoxic syndrome (tachycardia, the appearance of systolic murmur over the region of the heart, dizziness, shortness of breath). Pallor of the skin and mucous membranes is objectively noted;
- intoxication syndrome - weight loss, fever, increasing weakness, fatigue, increased night sweats, nausea, vomiting.
Chronic forms may be accompanied by similar, albeit less pronounced, signs of leukemia. Chronic leukemia has a slowly or moderately progressive course (from 4-6 to 8-12 years).
Diagnostics
Diagnosis of leukemia is carried out using laboratory, instrumental and morphological studies:
- general and biochemical blood test;
- cytogenetic, cytochemical and immunological analyzes - detection of surface cell differentiation antigens. To carry out such studies, specific monovalent antisera are used;
- puncture of bone marrow, enlarged lymph nodes, liver, spleen, skin infiltrates, etc. (trepanobiopsy);
- myelogram - a study of the cellular composition of the bone marrow;
- tomography and chest x-ray - in case of suspicion of damage to the lymph nodes of the mediastinum and the roots of the lungs;
- Ultrasound - allows you to detect an increase and small focal changes in the echogenicity of the liver, specific kidney damage;
- ECG - with suspicion of leukemic myocardial infiltration.
Leukemia treatment
Therapy for leukemia is differentiated, the choice of treatment methods depends on the morphological and cytochemical type of the disease. The main task of complex therapy is to rid the body of leukemic cells.
Source: oncology.eurodoctor.ru
The main treatments for leukemia:
- chemotherapy - treatment with various combinations of cytostatics in a high dosage (polychemotherapy);
- radiation therapy;
- bone marrow transplant - donor stem cell transplant (allogeneic transplant).
There are 5 stages of chemotherapy:
- The cytoreductive preliminary stage of treatment is carried out at the first attack of acute leukemia.
- Induction therapy.
- Consolidation of remission (2-3 courses).
- Re-induction therapy (repetition of the induction step).
- Supportive therapy.
With chronic leukemia in the preclinical stage, general strengthening treatment and constant medical supervision are sufficient. With clear signs of the transition of the disease into the phase of acceleration and blast crisis, cytostatic therapy is performed. For special indications, irradiation of lymph nodes, skin, spleen is used, splenectomy is performed. Allogeneic bone marrow transplantation can give good results.
Potential consequences and complications
Leukemia leads to inhibition of normal blood formation and can be accompanied by severe damage to the heart, liver, kidneys, spleen, lymph nodes and other organs and systems.
Forecast
The main factors influencing the prognosis of the course of the disease, along with the stage of the disease, are the prevalence of the lesion, the timing of the diagnosis, the genetic characteristics of cancer cells, the timing of the response to treatment. Leukemia in children with timely and rational treatment has a more favorable prognosis than in adults. Thanks to the optimization of therapy, the development of modern research protocols, it is possible to achieve remission of leukemia for many years and recovery. In general, the long-term prognosis for leukemia is poor.
Prevention
There is no specific primary prevention of leukemia, nonspecific is the exclusion of potential mutagenic factors (carcinogens) - ionizing radiation, toxic chemicals, etc. - on the body. Secondary prevention is reduced to careful monitoring of the patient's condition and anti-relapse treatment.
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Anna Kozlova Medical journalist About the author
Education: Rostov State Medical University, specialty "General Medicine".
The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!
