Lymphoblastic leukemia
The content of the article:
- Causes and risk factors
- Forms of the disease
- Disease stages
- Symptoms of lymphoblastic leukemia
- Diagnostics
- Lymphoblastic leukemia treatment
- Potential consequences and complications
- Forecast
- Prevention
Lymphoblastic leukemia is a malignant disease of the hematopoietic system, characterized by a rapid and uncontrolled increase in the number of lymphoblasts (immature lymphoid cells).
In pediatric practice, this is the most common cancer. In the general structure of the incidence of the hematopoietic system in children, the share of acute lymphoblastic leukemia accounts for 75-80%. Girls get sick less often than boys. The peak incidence occurs between the ages of one and six years.
Adults fall ill with lymphoblastic leukemia 10 times less often than children. The incidence rate increases among patients over 60 years of age.
In children, lymphoblastic leukemia usually develops as a primary disease, while in adult patients it often occurs as a complication of chronic lymphocytic leukemia.
Causes and risk factors
The development of acute lymphoblastic leukemia is caused by the formation of malignant clones in the red bone marrow, which are a group of hematopoietic cells that have lost the ability to control reproduction. Chromosomal aberrations lead to the formation of a clone:
- amplification - additional copies of a certain part of the chromosome are formed;
- inversion - rotation of a chromosome section;
- deletion - loss of a chromosome site;
- translocation - two chromosomes exchange certain areas with each other.
Genetic abnormalities that contribute to the development of lymphoblastic leukemia occur at the stage of intrauterine formation of the fetus. However, in order for the pathological process of the formation of clone cells to start, the influence of provoking external factors is necessary. These factors include:
- Exposure to ionizing radiation - repeated X-ray examinations, radiation therapy for other oncological diseases, living in a region with a naturally high radiation background. It is a proven fact that there is a relationship between radiation therapy and the development of lymphoblastic leukemia. According to medical statistics, the disease develops in 10% of patients undergoing radiation therapy. There is an assumption that the development of lymphoblastic leukemia can be triggered by X-ray studies, but this theory remains unconfirmed by statistical data.
- Infection with oncogenic virus strains. There is reason to believe that the development of acute lymphoblastic leukemia is caused by infection of a patient with a predisposition to leukemia with viruses, in particular, the Epstein-Barr virus. At the same time, it is known that the risk of developing lymphoblastic leukemia in children increases with the "untrained" of their immune system, that is, the absence or lack of experience of contact of the immune system with pathogenic microorganisms.
- Intoxication with oncogenic poisons, including heavy metal salts.
- Smoking, including passive smoking.
- Cytostatic therapy.
- Genetic abnormalities - hereditary immune disorders, celiac disease, neurofibromatosis, Wiskott-Aldrich syndrome, Klinefelter syndrome, Schwachmann's syndrome, Down syndrome, Fanconi anemia.
Forms of the disease
Lymphocytes are a type of agranulocyte leukocytes, the main functions of which are:
- production of antibodies (humoral immunity);
- direct destruction of foreign cells (cellular immunity);
- regulation of the activity of other types of cells.
In an adult, lymphocytes make up 25-40% of the total number of leukocytes. In children, their share can reach 50%.
Regulation of humoral immunity is provided by T-lymphocytes. T-helpers are responsible for stimulating the production of antibodies, and T-suppressors are responsible for inhibition.
B-lymphocytes recognize antigens (foreign structures) and develop specific antibodies against them.
NK lymphocytes control the quality of other cells in the human body and actively destroy those that are different from normal cells (malignant cells).
Source: medaboutme.ru
The process of formation and differentiation of lymphocytes begins with the formation of lymphoblasts - lymphoid progenitor cells. Due to the tumor process, the maturation of lymphocytes is disrupted. Depending on the type of lymphocyte damage, lymphoblastic leukemia is divided into T-linear and B-linear.
According to the WHO classification, several types of acute lymphoblastic leukemia are distinguished:
- pre-pre-B-cell;
- pre-B-cell;
- B-cell;
- T-cell.
In the overall structure of the incidence of lymphoblastic leukemia, B-cell forms account for 80-85%, and T-cell forms account for 15-20%.
Disease stages
During acute lymphoblastic leukemia, the following stages are distinguished:
- Initial. Lasts 1-3 months. The clinical picture is dominated by non-specific signs (pallor of the skin, low-grade fever, impaired appetite, fatigue, lethargy). Some patients complain of pain in muscles, joints and bones, abdomen, persistent headaches.
- It's high. Pronounced signs of the disease, manifested by anemic, intoxication, hyperplastic, hemorrhagic and infectious syndrome.
- Remission. It is characterized by the normalization of clinical and hematological parameters.
- Terminal stage. Characterized by rapid progression of symptoms of lymphoblastic leukemia. Ends with a lethal outcome.
Symptoms of lymphoblastic leukemia
The clinical course of acute lymphoblastic leukemia in children and adults is rapid. Often, by the time the disease is diagnosed, the mass of all lymphoblasts in the patient's body reaches 3-5% of the total body weight. This is due to the rapid proliferation of clone cells.
In the clinical picture of lymphoblastic leukemia, several syndromes are distinguished.
- Intoxicating. Its signs are: increased fatigue, severe general weakness, weight loss, fever, hyperhidrosis, general weakness. Fever can be associated both directly with the malignant process and with infectious complications.
- Hyperplastic. Lymphoblasts with blood flow spread throughout the body, accumulating in tissues, this process is called leukemic infiltration. It is manifested by an enlargement of the liver, spleen, lymph nodes, pain in joints and bones. Leukemic infiltration of the membranes and matter of the brain leads to the development of neuroleukemia. Clinically, it manifests itself as headache, nausea, and sometimes vomiting. When examining the fundus, swelling of the optic discs is noted. In some cases, neuroleukemia occurs with an erased clinical picture or is generally asymptomatic and is diagnosed only during laboratory examination of cerebrospinal fluid. In about 30% of boys, a symptom of lymphoblastic leukemia is the formation of infiltrates in the testicles. On the mucous membranes and skin of patients, leukemides (infiltrates of a purple-cyanotic color) often occur. In rare cases, hyperplastic syndrome is manifested by impaired renal excretory function, intestinal damage and effusion pericarditis.
- Anemic. The suppression of bone marrow hematopoiesis is accompanied by the development of anemia. Patients have pallor of the skin and mucous membranes, tachycardia, weakness, dizziness.
- Hemorrhagic. Thrombosis of capillary vessels and thrombocytopenia lead to the development of this syndrome. Multiple petechiae and ecchymosis appear on the skin. Even a minor bruise is accompanied by the appearance of an extensive subcutaneous hematoma. There are frequent nasal, gingival, uterine and gastrointestinal bleeding, retinal hemorrhages.
- Infectious. With lymphoblastic leukemia, lymphocytes do not fully differentiate, and therefore they are not able to perform their functions, which leads to a significant decrease in immunity. Because of this, patients become susceptible to viral, bacterial and fungal infections, which, moreover, take on a severe course and can lead to sepsis, infectious toxic shock.
Diagnostics
Diagnosis of acute lymphoblastic leukemia is based on symptoms, myelogram results, and peripheral blood tests. A general blood test for lymphoblastic leukemia reveals:
- decreased hemoglobin concentration (anemia);
- decreased platelet count (thrombocytopenia);
- an increased content of leukocytes (leukocytosis), less often there is a decrease in the number of leukocytes (leukopenia);
- increased ESR;
- the content of lymphoblasts is 15–20% of the total number of leukocytes;
- a decrease in the number of neutrophils (neutropenia).
In the myelogram, a pronounced suppression of neutrophilic, erythroid and platelet germs, the predominance of blast cells is determined.
Source: headexpert.ru
The comprehensive examination program for patients with lymphoblastic leukemia includes:
- lumbar puncture followed by laboratory examination of cerebrospinal fluid - to exclude or detect neuroleukemia;
- chest x-ray - in order to detect enlarged lymph nodes in the mediastinum;
- Ultrasound of the abdominal organs - assessment of the state of the intra-abdominal lymph nodes and parenchymal organs;
- biochemical blood test - to identify possible disorders of the kidneys and liver.
Acute lymphoblastic leukemia requires differential diagnosis with the following pathological conditions:
- infectious mononucleosis;
- other types of leukemia;
- poisoning;
- leukemia-like syndrome that occurs against the background of a severe course of certain infectious diseases (whooping cough, tuberculosis, cytomegalovirus infection, sepsis).
Lymphoblastic leukemia treatment
The main treatment for lymphoblastic leukemia is polychemotherapy - a type of chemotherapy in which not one, but several cytostatic drugs are used.
In the treatment of the disease, two stages are distinguished:
- Intensive or induction therapy. It is carried out in the conditions of the department of oncohematology for several months. Antineoplastic drugs are administered intravenously. The purpose of this stage is to normalize the processes of hematopoiesis (the absence of blasts in the peripheral blood and no more than 5% of them in the bone marrow) and to improve the general condition of patients.
- Supportive therapy. They have been carried out for several years on an outpatient basis. Antineoplastic drugs are prescribed in oral forms. The bone marrow and the composition of the peripheral blood of patients are regularly examined, if necessary, adjusting the treatment, for example, including radio or immunotherapy in the course.
With low efficiency of the treatment and repeated exacerbations, the question of the advisability of bone marrow transplantation is decided.
Potential consequences and complications
Against the background of acute lymphoblastic leukemia, patients experience a significant decrease in humoral and cellular immunity. As a result, they often develop infectious and inflammatory diseases (tonsillitis, sinusitis, pyelonephritis, pneumonia), which take a severe protracted course and can cause sepsis.
One of the main features of lymphoblastic leukemia is frequent leukemic infiltration of the nerve trunks, substance and membranes of the brain, leading to the development of neuroleukemia. Without the necessary prevention, this complication occurs in every second patient.
Forecast
In acute lymphoblastic leukemia in children, the prognosis is good. Modern polychemotherapy allows to achieve stable remission in 95% of patients in this age group. In 70-80% of them, the duration of remission is more than 5 years, such children are removed from the register as completely cured.
In adults, the prognosis for lymphoblastic leukemia is serious, the five-year survival rate does not exceed 34-40%.
Prevention
The specific prevention of lymphoblastic leukemia has not been developed. A healthy lifestyle (playing sports, giving up bad habits, proper nutrition, adherence to the daily routine) plays a certain role in preventing the disease.
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Elena Minkina Doctor anesthesiologist-resuscitator About the author
Education: graduated from the Tashkent State Medical Institute, specializing in general medicine in 1991. Repeatedly passed refresher courses.
Work experience: anesthesiologist-resuscitator of the city maternity complex, resuscitator of the hemodialysis department.
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!
