leucemia

Acute leuKemia/Leucemia in children

LeuKemia results in the replacement of normal blood cells in the bone marrow by cancer cells. Anemia, decreased leukocytes and platelets are symptoms of leukemia. Several treatments exist, including chemotherapy


Leukemia : definition


Leucemia is defined by a clonal proliferation (of a kind) of a precursor of blood cells in the marrow. An international classification defines different cytological types according to the cell line in question: lymphoid line or myeloid line. These diseases are serious.

However, the therapeutic advances are spectacular. The first extended remissions date back to the end of the 1960s. The most recent advances are a better approach to care (generalization of the use of central catheters, wide use of powerful antibiotics, better use of analgesics) and intensification of chemotherapy. (use of a course of intensification, better control of the marrow allograft). The understanding of leukemias has been greatly improved in recent years by molecular biology.

Acute leucemias are the most common childhood cancer, accounting for one third of pediatric cancers, with an annual incidence of 1.5 / 100,000. Acute leukemias are 20 times more common in children with trisomy. 21.

Leucemia results in the replacement of normal blood cells in the bone marrow by cancer cells. These abnormal cells prevent the marrow from making normal cells on the one hand and infiltrate the different organs on the other hand.

Spontaneous progression was rapidly fatal in tables of severe infections or major bleeding. Currently, modern therapies result in remission in more than 95% of cases of acute lymphoblastic Leucemia .

Causes and risk factors Leucemia

The application of molecular biology techniques to the areas of leukemia improves the understanding of these diseases. Recent work focuses on the early, molecular events responsible for leukemogenesis. As of now, these techniques improve the identification of the disease by allowing the definition of fusion transcript and the description of rearrangements between the immunoglobulin genes or the T-receptors.

The contributions of these techniques are twofold: better knowledge of the molecular definition of the disease and the possibility of monitoring the residual disease. The importance of in vitro testing techniques for the anti-leukemic activity of the various drugs should be noted. There is little work on the physiology of leukemic cells, except for studies of angio-genetic factors.

In the vast majority of cases, the cause or causes remain unknown. Infectious, probably viral agents could be involved. Among the infectious causes, EBV is associated with Burkitt’s lymphoma. Exposure to certain toxic substances (benzene, heavy metals), ionizing radiation or chemotherapy were mentioned as risk factors.

Symptoms of leucemia

The clinical signs reflect either bone marrow failure or visceral infiltration by abnormal cells. The medullary insufficiency entails:

A drop in red blood cells, therefore anemia: pallor, asthenia, loss of weight, deterioration of the general state;
A drop in leucocytes therefore a fragility vis-à-vis infections: trailing angina, unexplained fever …
A drop in platelets and thrombocytopenia: haemorrhages, epistaxis, petechiae, purpura, bruising etc … The retinal hemorrhages visible at the back of the eye are heralding cerebro-meningeal hemorrhages.
The infiltration of the organs by the leukemic cells causes:

An increase in the volume of the liver and / or spleen;
An increase in the volume of the lymph nodes;
Bone or osteoarticular pain;
Abdominal pain;
Hemorrhagic hypertrophy of the gums (gingivitis)
At the slightest doubt, the doctor calls on the laboratory.

NFS provides two types of information. Practiced early, at the “leueuemic” stage, the cancer cells have not yet appeared in the bloodstream. The blood test does not show them. In contrast, bone marrow failure results in:

The fall in the number of red blood cells: normochromic arteregenerative anemia;
Falling number of leukocytes: neutropenia;
The drop in the number of platelets: thrombocytopenia.
Later, it highlights the abnormal young cells (blasts) that have passed through the circulation. These results make it necessary to perform a marrow puncture in order to perform a smear or myelogram.null

There are two main forms:

Acute lymphoblastic leukemia or L.A.L., the most frequent between 18 months and 16 years, very sensitive to modern treatments since complete remissions are reached in more than 95% of cases for many months.
Acute myeloblastic leukemias or L.A.M. mainly affecting children over 12 years of age and older
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