The hematology is the branch of the Médecine which studies the Sang and its Maladie S (or Hémopathie S).
She studies more particularly the blood cells whose origin is hematopoietic (synthesis of these cells in osseous marrow) and who have a role for oxygenation, the immunity and the Coagulation, and studies also certain plasmatic molecules which are the factors of coagulation.
To have access under the terms frequently used in hematology to see vocabulary of hematology.
Distribution of the hematologic diseases in the population
FiguresThe serious hematologic diseases, that are the lymphomas and leukemias, are not very frequent cancers, they have in France an incidence of respectively 15 new cases and 7 new cases per annum and for 100.000 people.
Risk factorsThere are few risk factors listed for these diseases, one can quote:
- the exposure to certain chemicals
- the ionizing rays
For the defects of certain factors of coagulation and certain cells the risk factors are:
- mode low in iron
- mode low in certain vitamins
- abundant rules
Preventive measuresThe prevention simply consists in legislating and reducing the exposure to certain chemicals and ionizing rays, particularly in certain industries.
Fundamental disciplines in hematology
Anatomy and histology
Hematologic physiologyPhysiology makes it possible to know which are the mechanisms concerning a medical field and to thus better include/understand the diseases and to better diagnose them and guerrir them.
- the Hématopoïèse;
- genesis of cancers, to see Oncology;
List hematologic affections
The hematologic diseases are named Hémopathies.
Hematology is commonly divided into three pennies categories, according to the group of cells studied (red globules, leucocytes, Plaquettes). This subdivision remains incomplete, since many diseases affect some or all the components of the Sang and the osseous Moelle.
Most of the hémopathies is due either to the lack or with the excess of synthesis of these components of blood, for the blood cells it is about a problem at the time of a stage of the Hématopoïèse (synthesis of the blood cells in the bones) or in differentiations on the level of the secondary lymphoid bodies, and for the factors of coagulation of a problem to the liver.
It can also be a question of an excessive loss in periphery or synthesis of nonfunctional cells.
One thus finds in excess or certain cells in one or more of these compartments: osseous marrow, blood and the secondary lymphatic bodies.
One classifies the hémopathies as follows:
- on the one hand benign hémopathies (for example by vitamin deficiencies, anomalies of the Hemoglobin or Hémoglobinopathie…) whose classification suggested takes again this plan mainly.
- and in addition the malignant hémopathies:
- Leukemia S: tumor of blood (the blood cells proliferate in blood)
- Lymphome S: tumor in the secondary lymphoid bodies (such as for example the ganglia or spleen)
- As with other diseases which have these syndromes:
- Syndrome myelodysplasic: defect of synthesis of one or more of the types of following blood cells: red globules, white globules or plates
- and myéloprolifératif Syndrome: excess of synthesis of one or more of the types of following blood cells: red globules, white globules or plates
One distinguishes four types of Leucémie S:
- acute leukemia is characterized by the fast proliferation of immature cells of blood:
- lymphoid acute Leukemia (LAL): The cells concerned come from the lymphoid line;
- acute Leukemia myéloïde (LAM): The cells concerned come from the line myéloïde;
- chronic leukemia, here the cancer cells are more mature, the evolution is done over months at years:
As for the Lymphoma S, they are divided into two groups:
- the Disease of Hodgkin
- the lymphomas non-hodgkiniens
The diseases causing a problem of coagulation are the coagulopathies, among those Ci there are the diseases whose origin is the érythrocyte, but also those whose origin comes from the factors of coagulation, they are the hemophilia.
One can also classify the hémopathies according to the origin of the touched cell:
The white globules
- medullary Aplasia
- myéloprolifératif Syndrome (proliferation of cells of origin myéloïde)
- chronic Leukemia myéloïde
- Thrombocytémie essential
- Syndrome myelodysplasic
- lymphoprolifératif Syndrome (proliferation of cells of lymphoid origin)
- lymphoid acute Leukemia (LAL)
- chronic lymphoid Leukemia (LLC)
- Lymphoma S
- Disease of Hodgkin
- lymphomas non-hodgkiniens
- Others Adénopathie S that the lymphomas
- the plasmocytes
The red globules or red blood corpuscles
- Maladie of Be occupied
The blood plates
- Thrombosis S
- disorders related on the bleeding and the coagulation
- intravascular Hemophilia
- disseminated Coagulation
- Fibrinolyse thrombotic primitive
Principal clinical signsClinical signs:
- Adenopathy pathological (higher than 1cm, except the fold inguinal: higher than 2cm)
- Signs of Anemia
- Activity at the risk exposing to chemicals
- Exposure to the pathogenic ones such as contact with a cat or stay in zone of parasitic endémie
- Y' has you it have a risk of infection by the HIV
- Signes of Anémie
Complementary examinationsThe tests most used in the study of the hematologic problems are:
- the Hémogramme (or Numération Formulates Blood ) generally automated, makes it possible to highlight in hematology the following signs:
the consistent Myélogramme in the coloring of smear (for example thanks to the Method of Romanowsky)
- the Biopsy ostéomédullaire
- explorations of coagulation, they are times of coagulation in fact:
- Time of cephalin activated (TCA), (measurement the effect of cephalin injection, lipid close to the phosphatidyl serine)
- Time of Quick (TQ) modified in Intertionalized normalized ratio (INR), (measurement the effect of tissue injection of factor)
- Time of thrombin, (measurement the effect of thrombin injection)
TreatmentsThe treatments suggested are:
- the use of Drug S in particular the iron supplementation or vitamin in the Anemia S
- Produced blood unstable (P.S.L.)
- concentrated globular (in anemias and hemorrhages)
- concentrated plate (in the thrombopénies)
- fresh Plasma frozen (in the Coagulopathie S)
- Drugs blood derivative
- coagulating fractions (FVIII, FIX, PPSB in the intoxications with the vitamin K)
- plasmatic albumin (in the nephrotic syndromes)
the Phlébotomie or bled (for the Hémochromatose or the Polycythémie)
- the Transplantation of osseous marrow (for example for the Leukemia)
- the Chemotherapy (for example for the Leukemia)
- the Radiotherapy (less and less used, especially for the Lymphoma S)
It should be noted that for the blood transfusions, it is necessary to resort to voluntary donors, either voluntary (in France in particular) or remunerated. This collection of blood is assured either by a public service (in France) or an ONG (Red Cross), or by private firms. The transfusional site which provides the products to the clinicians users is sometimes called " bank of the sang".
History of hematology
Books on hematology
- French company of hematology
Notes and references of the article
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