Leukemia

Leukemia : It is a group of malignant diseases of the bone marrow, also known as leukosis, hematological cancer , which causes an uncontrolled increase in clonal leukocytes (white blood cells) in the bone marrow , which usually pass into the peripheral blood although sometimes they do not. they do ( aleukemic leukemias ). Certain malignant proliferations of red blood cells are included among the leukemias erythroleukemia . Uncontrolled proliferation or reproduction in the bone marrow and accumulate both there and in the blood, managing to replace normal cells.

Summary

[ disguise ]

• 1 Etymology
• 2 Features
• 3 Causes
• 4 Signs and symptoms
• 5 Diagnosis
• 6 Classification
• 7 There are different types, according to the leukocyte population they damage:
• 8 Forms of presentation
  • 1 Some of its most important clinical manifestations are:
• 9 Bone marrow aspiration:
• 10 Fonts

Etymology

Literally, it means “white blood”; The word is made up of two Greek elements: leuc, a variant of white leuco”; and emia “blood”.

Characteristics

The main characteristic of acute leukemias is the presence of a “maturation cessation” of myeloid (AML) or lymphoid (ALL) lineage cells with blastosis in the bone marrow (greater than 20% non-erythroid cellularity according to the WHO). Given that there is still residual normal hematopoiesis , the existence of a ” leukemic hiatus ” can be seen in peripheral blood, that is, the presence of immature forms in peripheral blood and mature forms but with the absence of intermediate elements. In chronic leukemias, the main characteristic Morphological is the non-existence of said leukemic hiatus, since there is no maturation stop, allowing mature cells to be secreted into the blood, and its clinical course is usually indolent.

Causes

The cause of leukemia is unknown in most cases. However, it has been proven that it is not a hereditary or contagious condition. Most of the time it occurs in previously healthy children. Because it is a proliferation of immature and abnormal cells in the blood, leukemia is considered a “blood cancer,” like other types of cancers the result of somatic mutations in DNA.

Certain mutations occur by activating leukemia oncogenes or deactivating tumor suppressor genes, thereby altering the regulation of cell death, differentiation or division. These mutations can occur spontaneously or as a result of exposure to radiation or carcinogenic substances , and are likely influenced by genetic factors.

Among adults, known causes are natural and artificial ionizing radiation , some viruses such as the human T-lymphotropic virus , and benzene, some chemicals, particularly alkylating agents, and chemotherapy for earlier diseases.

Tobacco use, studies are associated with a small increase in the risk of developing acute myeloid leukemia in adults. Exposure to some petrochemicals and hair dyes can cause the development of some forms of leukemia. A few cases of maternal-fetal transmission have been reported. The diet has little or no effect, although eating more vegetables may confer a small protective benefit.

Viruses have also been linked to some forms of leukemia. Experiments in mice and other mammals have demonstrated the relevance of leukemia retroviruses and human retroviruses have also been identified.

The first human retrovirus identified was human T-lymphotropic virus or HTLV-1, it is known to cause T-cell leukemia. Some people have a genetic predisposition toward developing leukemia. This predisposition is demonstrated by family histories and twin studies.

Affected people may have a single gene or multiple genes in common. In some cases, families tend to develop the same type of leukemia as other members; In other families, affected people may develop different forms of leukemia or blood-related cancers.

In addition to these genetic issues, people with chromosomal abnormalities or certain other genetic diseases have a higher risk of leukemia. For example, people with Down syndrome have a significantly increased risk of developing forms of acute leukemia and Fanconi anemia is a risk factor for developing acute myeloid leukemia.

Signs and symptoms

Acute lymphoblastic leukemia

Damage to the bone marrow, by way of displacing normal bone marrow cells with a greater number of immature white blood cells, results in a lack of platelets in the blood, which are important in the blood clotting process . This means that people with leukemia can easily develop bruising, excessive bleeding, or pinprick-type hemorrhages ( petechiae ). White blood cells, which are involved in fighting pathogens , can be suppressed or dysfunctional. This could cause the patient’s immune system to be unable to fight a simple infection or weak to attack the cells of another organism. Because leukemia prevents the immune system from functioning normally, some patients experience frequent infections, ranging from infected tonsils, mouth sores, diarrhea, pneumonia, or opportunistic infections . Finally, red blood cell deficiency causes anemia , which can cause dyspnea and paleness. Some patients experience other symptoms. These symptoms may include nausea, fever, chills, feeling fatigued, night sweats, and other flu-like symptoms. Some patients experience nausea or a feeling of fullness due to the enlargement of the liver and spleen, which can result in unintentional weight loss. If leukemic cells invade the central nervous system, neurological symptoms (especially headaches) may occur. All symptoms associated with leukemia can be attributed to other diseases. Consequently, leukemia is always diagnosed through medical tests.
The word leukemia, meaning “white blood,” is derived from the high number of white blood cells that most leukemia patients have before treatment. The high number of white blood cells is evident when an affected blood sample is observed under the microscope. Often, these extra white cells are immature or dysfunctional. The excessive number of cells can also interfere with the level of other cells, causing a harmful imbalance in blood ratio. Some leukemia patients do not have a high number of white blood cells visible during a normal blood count. This less common condition is called aleukemia.. The bone marrow contains cancerous white blood cells that disrupt the normal production of blood cells. However, the leukemic cells lodge in the marrow instead of entering the bloodstream, where they would be visible in a blood test. For a leukemic patient, the white blood cell count may be normal or low. Aleukemia can occur in any of the four main types of leukemia, and is particularly common in hairy cell leukemia .

Diagnosis

Diagnosis is usually based on repeated complete blood counts and a bone marrow examination after symptoms are observed. A lymph node biopsy may also be performed to diagnose certain types of leukemia in certain situations. After diagnosis, blood chemistry tests can be used to determine the degree of damage to the liver and kidneys or the effects of chemotherapy on the patient. When concerns arise about visible damage due to leukemia, doctors may use x-rays, MRI, or ultrasound. These effects can potentially see leukemia in parts of the body such as the bones x-rays, the brain MRI, or the kidneys, spleen and liver (ultrasounds). Lastly, CT scans are rarely used to check lymph nodes in the chest. Despite the use of these methods to diagnose whether a patient has leukemia, many people have not been diagnosed, due to the fact that many of the symptoms are vague, nonspecific, and may refer to other diseases. For this reason, it is predicted that at least one fifth of people with leukemia have not yet been diagnosed.

Classification

There are four main types of leukemia, named based on the speed of progression and the type of white blood cell they affect. Acute leukemias progress rapidly; Chronic leukemias develop slowly. Lymphatic leukemias affect lymphocytes; Myeloid (myelocytic) leukemias affect myelocytes. Myelocytes transform into granulocytes, another way of calling neutrophils.

There are different types, according to the leukocyte population they damage:

• Chronic myeloid leukemia : (CML) included within chronic myeloproliferative syndromes.
• Chronic lymphoid leukemia : (CLL) included within lymphoproliferative syndromes and comparable to lymphocytic lymphoma.
• Acute lymphoid leukemia : Lymphoblastic leukemia (ALL)
• Acute myeloid leukemia : Myeloblastic leukemia (AML)
• Myelogenous leukemia (ML)

In addition to leukemized non-Hogdkin lymphomas , that is, with the presence of lymphomatous cells in the peripheral blood, as occurs in Tricholeukemia.

Forms of presentation

Although some leukemias have a fulminant nature, others may be indolent diseases, with an insidious presentation. Since there is no symptom that alone and specifically allows the diagnosis of this disease, the presence of leukemia should always be ruled out in the presence of suggestive clinical manifestations, such as an altered blood count. The safest method to confirm or rule out the diagnosis is by performing a myelogram and, only in selected cases, a bone marrow biopsy may be necessary.

Some of its most important clinical manifestations are:

• Compromise of general condition: weakness, lack of strength, dizziness, nausea, loss of appetite, significant weight loss.
• Fever that lasts several days without an apparent cause, night sweats, chills.
• Bone pain or tenderness, joint and extremity pain.
• Frequent bleeding for no apparent reason, for example, abnormal bleeding from the gums or nose.
• Petechiae (Small red spots due to blood extravasation) or Hematomas without having had any blows.
• Pale skin, inside the oral cavity or eyelids.
• Enlargement of lymph nodes.
• Appearance of masses or abnormal growths of abdominal organs such as the spleen and liver, or appearance of masses that grow in other parts of the body.
• Alterations in blood tests (CBC, HIV, etc.).
• Irregularity in menstrual cycles.

Bone marrow aspiration:

In a bone marrow aspiration, a small portion of the bone is removed. The procedure is annoying, but both children

as adults can tolerate it quite well. The bone marrow may be examined to determine the cause of anemia, the presence of leukemia or another cancer, or the presence of some “storage diseases,” in which metabolic products are stored in certain marrow cells.