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What is the disease leukemia in humans

What is leukemia?

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Leukemia (leukemia, leukemia) is a cancer of the blood. The essence of this type of cancer is the genetic variance of some of the cells that circulate in the blood and are produced in the bone marrow.

Because of cells and the stages of their development very much, there is also a range of leukemia called "myeloproliferative and lymphoproliferative diseases" (proliferation = multiplication or division, i.e. multiplication of tumor cells).

Many of them are relatively less serious nature, however, can go one way or the other classic form of leukemia. Examples are:

  1. Myelodysplastic syndrome.
  2. Osler.
  3. Relative thrombocythemia.
  4. Primary myelofibrosis, and others.

The most common symptoms include increased bleeding and blood clotting.

To lymphoproliferative diseases include lymphomas, cancerous tumors that arise from blood cells, as well as leukemia, but, in contrast, are located in the lymph nodes (eg, in the neck, underarms, groin area) that swell, which makes the tumor visible.

Classic leukemia "invisible" because the disease is in the blood vessel, in no way increasing. In some cases it happens that lakeside lymphoma, i.e. cancer cells get into the blood and, conversely, leukemia brings about the cancer cells in a specific organ – lymph nodes (i.e., takes the form of lymphoma), spleen or liver, and is localized there.

Classification

There are 4 main types of leukemia (i.e., leukemia in the true sense of the word – not lymphoma, polycythemia Vera, thrombocythemia, etc.):

  1. Acute myeloid leukemia.
  2. Chronic myelogenous leukemia.
  3. Acute lymphoblastic leukaemia.
  4. Chronic lymphocytic leukemia.

    CHto takoe bolezn lejkemiya u cheloveka

The word "acute" suggests a more rapid progression of disease, the word "chronic" is a slower, but sometimes even the development of acute leukemia takes more time than its chronic forms, depending, of course, from the treatment.

Some have other leukemia subtypes, depending on the maturity of cells, this applies especially to acute myeloid leukemia. In order to get a glimpse into medical terminology and understanding of various leukemias, below is a brief overview of red blood cells.

Blood cell

Blood cells (blood cells) are divided into 2 main groups:

  • Red blood cells (erythrocytes).
  • White blood cells (leukocytes).

To blood cells and platelets are involved in blood clotting.

White cells are divided into several types, the most important are lymphocytes that produce antibodies (B-lymphocytes) and play a significant role in the immune system in protection from infections and tumors (T lymphocytes).

Other important white blood cellsbelong to the so-called neutrophilic granulocytes (abbr. neutrophils) that protect the body from bacterial infections.

In the bone marrow, where hematopoiesis takes place normally, each person has a certain number of stem cells, which are immature and is able to Mature into any type of cell in a red or white line. When "sick" stem cell, it is subsequently affected by the same genetic defect in all of its daughter cells, and it can go as red and white blood bodies.

More often, however, leads to cell damage at a lower level of development – immature lymphocytes or neutrophils.

Stem cells produce 2 main lines:

  • lymphoid, which, in turn, is divided into T and b (depending on b-lymphocytes and T-lymphocytes),
  • myeloid, which includes the precursors of red blood cells, neutrophils, platelets, and other cells. Hence the name "myeloproliferative" (myelo = something to do with the bone marrow) and "lymphoproliferative" disorders.

Acute myeloid leukemia

This is leukemia, which occurs mainly in older age, although can also occur in children under the age of 15. The incidence is 3-4 cases per 100,000 inhabitants per year, however, at the age of 65+ years accounts for up to 15 cases per 100,000 inhabitants per year.

CHto takoe bolezn lejkemiya u cheloveka

Because of the myeloid lineage, there are many types of cells (red blood cells, platelets, and leukocytes, of which it is, mostly neutrophils and monocytes), there are more subtypes of leukemia, in accordance with the stages of development of the affected cells. From where the type in question, much depends on the prognosis of the patient.

The number of white blood cells varies from individuals. in some people, the number may be 10 times higher, others a normal or slightly reduced. The more sick of white blood cells, the more serious the disease. White blood cells, as already mentioned, although desirable to protect the body from infections, but in the case of their disease, they become virtually non-functional and man, on the contrary, is under threat of infection, which can not resist.

Risk factors for development of acute myeloid leukemia

In the origin of leukaemia of this type play an important role environmental factors, such as different chemicals (benzene, phosgene, alkylating agents, etc.), as well as ionizing radiation. This is evidenced by high frequency of occurrence of this disease after the explosion of the atomic bomb in Japan.

Other factors are viral infections. Some people have an innate predisposition to leukemia, and this means that the risk of disease is much higher than in people who do not have this genetic predisposition. We are talking primarily about people with down syndrome, Klinefelter syndrome, Fanconi anemia and disease of Recklinghausen (neurofibromatosis). All these people were somehow disrupted gene, therefore any other small deviations for the occurrence of leukemia, while, in healthy humans, need at least 2 variations.

People who have myelodysplastic syndrome or true polycythemia, are also at risk of developing leukemia. Myelodysplastic syndrome (MDS) is sometimes a precursor to acute myeloid leukemia, in polycythemia risk of developing leukemia is about 1-2%.

Progress and symptoms of acute myeloid leukemia

Symptoms as with other types of leukemia are nonspecific and very bright. The disease may initially look like the flu. The person feels fatigue, weakness, there is a high temperature.

Almost half of the people the first symptom that leads them to the doctor, are small subcutaneous hemorrhage, often pointed or in the form of bruises. Can also occur frequent or excessive bleeding from the nose and gums. Severe bleeding is rare.

These symptoms are caused by bone-marrow suppression in connection with the increase in the number of leukemic cells, therefore, blood is present less than the normal number of red blood cells anemia occurs, fewer platelets that causes bleeding (due to blood clotting), and fewer neutrophils, which could be reached by the frequent development of infections against which the body loses its defensive properties.

Diagnosis of acute myeloid leukemia

In the diagnosis of leukemia, it is important blood tests and bone marrow biopsy.

In acute myeloid leukemia is also crucial immunological and cytogenetic analysis, which recognized a variety of genetic variations, some of which determine a good prognosis, others poor.

The treatment of acute myeloid leukemia

The goal of treatment is to rid the person from leukemic cells, ideally, eliminate them altogether. Today there are various treatments and procedures that somewhat vary, depending on leukemia subtype. Despite the great popularity and great success of cell transplantation, it should be emphasized that the most important therapeutic method is chemotherapy.

Chronicmyeloid

This type of leukemia is about 25% of all leukemias, therefore, occurs at a frequency of 1-2 cases per 100,000 people per year. Most often the disease develops in the age group of 45-55 years, with a slightly higher frequency in men. In children the illness is very rare.

A characteristic feature of chronic myeloid leukemia is the presence of the so-called Philadelphia chromosome. This chromosome represents a component of cell nuclei and persists as individual measurements of genes (i.e. DNA). In the cell chromosomes have a few, but with this type of leukemia chromosome 22 is shortened, and it is connected 2 gene, which otherwise belong to another chromosome. Connecting with each other, they create problems that lie in the excessive proliferation of leukemic cells and increased resistance to their death. However, in people with Philadelphia chromosome have a better prognosis compared to those who are absent (5% of cases of chronic myeloid leukemia).

Risk factors for development of chronic myeloid leukemia

As in the case of acute myeloid leukemia, the disease can contribute to environmental factors – ionizing radiation and chemical substances.

A risk factor is also already mentioned the Philadelphia chromosome.

The symptoms and course of chronic myeloid leukemia

Onset may be obscure, so the diagnosis is often determined on the basis of random blood test. Sometimes this type of leukemia, affects the pressure in the left hypochondrium and a feeling of fullness in the upper abdomen. This is caused by enlargement of the spleen, which also infiltrating leukemic cells. Sometimes it comes to inflammation of the spleen, which is manifested by severe pain, irradiiruet in the left shoulder.

Nonspecific symptoms include the following phenomena:

  1. Fever.
  2. Sweating.
  3. Weight loss.
  4. People suffering from anemia, lack of red blood cells and, thus, shortness of breath.
  5. Sometimes, pain in the bones, indicating increased bone decay (osteoporosis) in the expansion of leukemic cells in the bone marrow.
  6. In addition, can develop infectious diseases, neurological disorders, such as visual impairment.

Diagnosis of chronic myeloid leukemia

Studies are almost the same as in acute myeloid leukemia. Laboratory tests in addition to the data on blood cells in the blood and bone marrow may show increased concentrations of vitamin B12 and calcium levels, which is associated with the degradation of bone tissue (osteoporosis) and disappearance of leukemic cells.

Treatment of chronic myeloid leukemia

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Initially fatal disease today some patients can be cured, or by treatment can be achieved in different ways long temporary recovery (remission) in which the normal amount of blood and the symptoms of the disease disappear.

The only method that can actually lead to a complete cure is stem cell transplantation. Cell transplantation from unrelated donors is always risky, so it is advisable to give preference to autologous transplantation (selection of cells from your own body).

Acute lymphoblastic leukaemia

The disease is the most common type of leukemia in children and the most common form of cancer in the age group of about 4 years. In adults is a relatively harsh form of the illness most often affects people older than 50 years. Total, it is reported about 5-7 cases per 100 000 population.

The disease can develop from either b-cells (often) or T lymphocytes (less common).

Risk factors for development of acute lymphocytic leukemia

As in the case of acute myeloid leukemia risk group consists of patients with defined hereditary syndromes – down syndrome, neurofibromatosis, and Fanconi anemia.

More than 85% of patients with leukemia detected some defects in the chromosomes that are closely associated with their forecast. For example, the presence of the Philadelphia chromosome (see chronic myeloid leukemia).

Progress and symptoms of acute lymphocytic leukemia

Common symptoms such as fatigue, weakness, anemia and bleeding are similar to acute myeloid leukemia. Compared to her, however, often causes pain in the joints and bones, because the leukemic cells invade the bone marrow.

Often slightly enlarged lymph nodes and spleen, which can cause the pressure in the left upper hypochondrium, seldom increases the liver. From 5-13% of patients the leukemic cells also penetrate the meninges, causing some neurological symptoms – blurred vision, headache, etc. in 10-15% of men affected and the testes, which consequently can be increased.

Diagnosis of acute lymphocytic leukemia

Important for proper diagnosis is laboratory of immunological and cytogenetic study of blood.

Standard procedures include testing of cerebrospinal fluid (lumbar puncture), and examination by a ophthalmologist to determine whether there are leukemic cells in the brain.

The treatment of acute lymphocytic leukemia

The primary therapy as in acutemyeloid leukemia is chemotherapy. Is used primarily, Vincristine, Daunorubicin, Asparaginase, Cyclophosphamide and Corticosteroids (Prednisone). Usually, drugs are administered intravenously.

Chronic lymphocytic leukemia

This is the most common type of leukemia, which, fortunately, has the best prognosis. Each year there are 30 cases per 100 000 population. Predominantly affects men older than 50 years.

As in the previous case of acute leukemia, the disease based on the b lymphocytes.

Risk factors for development of chronic lymphocytic leukemia

In contrast to other leukemias, the disease is not associated with ionizing radiation. The origins of this leukemia are likely purely genetic.

Progress and symptoms of chronic lymphocytic leukemia

The disease is chronic in nature, that is, as a rule, lasts much longer compared to acute leukemia.

Initially, the disease is mostly asymptomatic, the diagnosis is determined based on a random blood test. In the later stages the person has enlarged lymph nodes (submandibular, cervical, supraclavicular, underarms, or groin).

Diagnosis of chronic lymphocytic leukemia

As always, blood test and bone marrow study. Of particular importance in this test, cytogenetic study, which shows the presence or absence of certain "bad genes". In accordance with the results of the survey is determined and treatment.

Treatment of chronic lymphocytic leukemia

The therapy is based on the use of Cytotoxic drugs – fludarabine (Fluder) and Cyclophosphamide or Chlorambucil.

Corticosteroids are used to treat complications. They are used in transplantation antibodies.