Leukemia: types, classification, forms and characteristics of treatment

In the article, we will consider the classification, forms and types of leukemia.

Leukemia (bleeding, leukemia) is a clonal disease of the hematopoietic system. This name unites a whole group of pathologies. The development of this disease is due to the transformation and mutation of cells that are in the bone marrow and are responsible for the process of hematopoiesis. There are several types of leukemia, and among other cancer diseases, these ailments are not the most common. The most common pathology occurs in children aged three to four years, as well as in the elderly (60-70 years).

Types of leukemia are described in detail below.

Etymology and Pathogenesis

At the moment, the exact cause of leukemia is not known to medicine. Nevertheless, scientists have established factors that are considered fundamental in the development of this ailment:

1. Genetic. It is believed that the presence of leukemia in a blood relative 3-4 times increases the likelihood of developing pathology in future generations. The genetic factor determines the manifestation of leukemia in children.
2. Carcinogenic, chemical. This factor involves the use of certain medications intended for the treatment of various pathological conditions. First of all, they include penicillin antibiotics. This factor also includes prolonged and systematic contact with various kinds of polymer paints, varnishes, detergents.
3. Viral and infectious diseases carried by the patient throughout life. Scientists suggest that the virus that enters the human body interacts with healthy cells and thereby causes the process of their pathological degeneration and irreversible mutation. This factor is considered provoking, contributing to the nucleation and development of malignant tumors.
4. Radiation. When exposed to radioactive rays on the body, the risk of developing this pathology increases significantly.

Stages

Regardless of the type of leukemia, each of them passes through the following stages in its development:

1. Stage of initiation. Under the influence of any factor, tumor degeneration of hematopoietic stem cells begins . This is due to damage to the pro-oncogenes that turn into oncogenes, as well as the defeat of anti-oncogenes.
2. Promotion stage. Uncontrolled growth and multiplication of transformed cells in the bone marrow begins. In parallel, leukemic clones are formed. This stage can last for several years, and it does not manifest itself clinically.
3. Stage of progression. A monoclonal tumor begins to turn into a polyclonal one.
4. Stage of metastasis. At this stage, the pathological hematopoiesis goes beyond the bone marrow. It spreads to other tissues and organs (liver, lymph nodes). This process is due to the proliferation of diseased cells. As a result, the organs increase, their dysfunction is observed.

Types of Leukemia

In the process of development of pathology, certain types of blood cells are converted to malignant. In this regard, there is a classification of leukemia based on the type of lesion.

In accordance with this, there are two types of leukemia: lymphocytic leukemia and myeloid leukemia. Each of them, in turn, may have an acute or chronic form.

It should be noted that the classification for chronic or acute forms is not based on the nature of the course of the disease. The specificity of the classification is that these two forms are not interconnected and cannot flow into each other. Only in rare cases, a chronic disease can be complicated by an acute course.

The types, causes and symptoms of acute leukemia are of interest to many.

In the development of the disease, a latent period and a period of symptom expression are distinguished. The first period is characterized by the absence of clinical symptoms. Cell proliferation occurs, but their number is not at a critical level. The latency period is from several months to several years. The period of expression of symptoms is characterized by a decrease in the functionality of the hematopoietic system as a result of a critical level of the number of tumor cells.

Syndromes

All clinical manifestations of leukemia are divided into 4 groups of syndromes:

1. Hyperplastic syndromes. Characteristic signs of hyperplastic syndromes are an increase and soreness of the lymph nodes, an increase in the spleen and liver, the appearance of pain and aches in the joints, the appearance of reddish-bluish plaques on the skin, damage to the oral mucosa, tonsils, the development of necrotic stomatitis, gum hyperplasia. Syndromes are caused by leukemic infiltration of the spleen, liver, joint capsule and periosteum, as well as a tumor increase in bone marrow volume.
2. Hemorrhagic syndromes. Manifested by the occurrence of bleeding and hemorrhage (gingival, nasal, internal). Very often causeless bruises appear, even a minor injury can cause almost unstoppable bleeding, wounds heal over a long period. Syndromes are caused by a blood clotting disorder due to platelet damage.
3. Anemic syndromes. Weight loss, palpitations, hair loss, general malaise, pallor of the skin, memory impairment and loss of concentration are observed. Syndromes are caused by a decrease in hemoglobin, as there are not enough red blood cells in the blood.
4. Immunodeficiency and intoxication syndromes. They appear in the form of weakness, fever, excessive sweating, headache, nausea and vomiting, lack of appetite, significant weight loss, the development of various infectious and inflammatory processes that are very difficult.

Each type of leukemia has its own specific symptoms. They also differ in the course of pathology.

So what are the main types of leukemia?

Acute lymphoblastic leukemia

This type of disease most often affects children and people at a young age.

The disease is characterized by a rapid increase in the number of blasts - immature cells, the precursors of lymphocytes. They accumulate in the lymph nodes, the spleen, creating an obstacle to the formation and functioning of normal blood components.

Patients often complain of fatigue, periodic joint pain. Some of them note an increase in cervical, inguinal and axillary lymph nodes. After some time, severe manifestations of the disease begin to be observed.

This type of acute leukemia may be suspected if you have the following symptoms:

1. Severe sore throat.
2. Anemia, in which the white blood cell count rises sharply, while the platelet count decreases.
3. The spleen increases.
4. The temperature rises. It can be slightly elevated or constantly high.
5. Gum bleeding increases, nosebleeds often occur, and a tendency to bruising as a result of minor injuries appears.
6. Damage to the ribs, clavicles and bones of the skull with infiltration.

This type - acute lymphoblastic leukemia - most often manifests itself in children aged 3-6 years. Symptoms are as follows:

1. The spleen and liver increase, against the background of which the size of the abdomen in the child significantly increases.
2. Lymph nodes increase. The enlargement of the chest lymph nodes is accompanied by the appearance of shortness of breath and a painful dry cough.
3. With this type of leukemia in children, pain occurs in the abdomen and legs.
4. The child has pale skin, quickly gets tired.
5. When infected with acute respiratory viral infections, severe manifestations are observed.
6. The child often falls, loses balance.

What other types of acute leukemia exist?

Acute myeloid leukemia

This type of leukemia often affects adult and elderly patients. It is very difficult to recognize it; it is characterized by uncontrolled growth and accumulation of cells of a hematopoietic nature. Acute myeloid leukemia is localized in the bone marrow and in peripheral blood.

This type of leukemia does not have characteristic symptoms. Most often, patients note the appearance of bone pain, fever, fatigue, pallor and cyanosis of the skin, the appearance of shortness of breath and a decrease in appetite.

Reduced platelet count causes excessive blood loss when injured or injured. As a result of a decrease in the level of full white blood cells, immunity is suppressed, infectious diseases occur more often, chronic ones worsen and become resistant to therapy. In acute myeloid leukemia, swelling may appear on the gums, lesions of the gastrointestinal mucosa and mouth are not ruled out.

Consider also the types of leukemia in adults.

Chronic lymphoblastic leukemia

This disease affects people over the age of 50. It has a long course. The accumulation of tumor lymphocytes in the peripheral blood, spleen, liver, lymph nodes, bone marrow is characterized.

The main difference from acute lymphoblastic leukemia is the slow growth of the tumor. Only in the later stages of the disease are hematopoiesis disorders observed.

The first and main symptom of chronic lymphoblastic leukemia is an enlargement of the spleen and lymph nodes. The patient feels pain in the hypochondrium on the left. In addition, the disease is accompanied by symptoms characteristic of other types of leukemia, but they develop over a long period.

About a quarter of cases of the disease are detected as a result of a laboratory blood test prescribed for another ailment. The analysis shows a significantly increased number of lymphocytes (up to 95%). A significantly reduced level of red blood cells and, as a result, hemoglobin is observed. The chronic course of this type of leukemia in adults can last 3-7 years.

Chronic myeloid leukemia

This type of disease is the most common. Most often, adults are exposed to it. Doctors believe that the predisposition to this pathology is due to heredity and is interconnected with a chromosome defect.

The initial stages of the disease do not have pronounced manifestations, they are almost never detected during diagnosis. Leukemia can be detected by chance during a laboratory blood test. It detects an unexplained increased number of white blood cells, an increase in the number of eosinophils and basophils, which have different degrees of maturity. There are no signs of anemia.

Most often, a chronic type of leukemia is found, which can last several years. It is worth noting that this type of leukemia is well controlled with medication.

At this stage, the disease begins to manifest itself in the form of fever, fatigue, weight loss, pain in the left hypochondrium against the background of an increase in the size of the spleen, an increase in the size of the liver.

The bone marrow at this stage contains approximately 5% of blasts. Quite often, at this time, there is a suspicion of the presence of chronic myeloid leukemia. Treatment involves a course of chemotherapy, which results in a period of remission. Subject to the prescribed treatment, the state of remission can last more than 5 years.

We continue the cytomorphological characterization of various types of leukemia.

Hairy cell lymphocytic and juvenile myelomonocytic leukemia

These forms of leukemia are observed in different age groups.

A special form of leukemia is juvenile myelomonocytic. This disease affects children two to four years old. This type of leukemia is the rarest of all. More common in boys. Doctors believe that the reason for its development lies in heredity.

Symptoms of juvenile myelomonocytic leukemia are manifested in the form of signs of anemia: bleeding gums, nosebleeds, physical underdevelopment, which is expressed by a lack of growth and weight.

A distinctive feature of this type of leukemia is the sudden onset. If a pathology is detected, urgent medical intervention is necessary. However, therapeutic methods in this case are powerless, and the only chance of cure is an allogeneic bone marrow transplant.

A very rare disease is hairy cell lymphocytic leukemia. Risk group - people over the age of 50 years. The course of the disease is very long and slow. This type of leukemia can be refractory, progressive, untreated.

The first two are the most common. Symptoms of the disease are often attributed to the age of the patient, as a result, it proceeds hidden. In the blood test, an elevated ten, and sometimes a hundred times, level of leukocytes is found. Hemoglobin, platelet and red blood cell counts are reduced to a minimum.

Below are the types of blood leukemia in adults in the table.

Animal leukemia

Quite often leukemia occurs in animals. However, unlike human leukemia, animal disease is viral in nature.

Hemoblastosis (leukemia, bleeding, leukemia) is a tumorous disease that affects the hematopoietic tissue of animals. The disease is characterized by a violation of the hematopoiesis process, which is expressed in the uncontrolled reproduction of pathological leukemia cells that have not reached maturity. It can be observed not only in the organs of hematopoiesis, but also in other systems and organs. Of farm animals, leukemia is most often found in cows, of birds - in chickens. There are many forms of animal leukemia. Lymphocytic leukemia in cattle, as well as various forms of bird leukemia, cause the greatest economic damage to livestock.

The spread of leukemia in certain animal species occurs as a result of exposure to oncornaviruses belonging to the family Retraviridae. Their development is more dependent on the immunological state of the animal and the genetic predisposition to the disease.

There is no direct relationship between leukemia in farm animals and humans. It should be noted that in animals under the influence of chemical and radiation factors, various types and forms of leukemia can develop.

Leukemia proceeds quite a long time, which can be up to several years. In most cases, specific clinical signs are not detected. As a result of the proliferation of tumor-shaped inferior cells, as well as against the background of leukemic infiltration of various organs, a general intoxication of the animal’s body occurs, the function of the affected systems and organs is impaired, and general exhaustion is observed.

How is the diagnosis made?

The diagnosis is established on the basis of a laboratory blood test that detects an increased amount of lymphoid and myeloid leukocytes in the blood, as well as an increased percentage of lymphocytes. Also, the disease can be detected by histological or pathological examination.

Therapy of leukemia in animals is considered irrational. Preventive measures and methods of combating leukemia include protective measures aimed at protecting households from infection, as well as timely vaccination of livestock.

We examined the types and signs of leukemia (leukemia).