Eucosis (Hemoblastosis)

Hemoblastosis is a disease of the whole blood system characterized by:

1. progressive cell hyperplasia in the hemopoietic organs with pronounced prevalence of proliferation of certain cells;

2. metaplasia of these pathological cells instead of normal cells to hemopoietic organs;

3. development of pathological foci of hemopoiesis in various organs.

Classification of hemoblastosis

Primary affection of the bone marrow		Tumor growth outsides the marrow bone
Myeloproliferative disorders	Lymphoproliferative disorders	Hodgkin's disease Malignant lymphoma Reticulosarcoma Limphosarcoma
Acute myeloblastic leukemia Chronic myelocytic leukemia Polycythemia vera Myelofibrosis leukemia	Acute lymphoblastic leukemia Chronic lymphocytic leukemia Multiple myeloma

Acute myeloblastic leukemia

Acute myeloblastic leukemia is characterized by profuse proliferation of the blast clement of blood with their subsequent disturbed differentiation, with development of foci pathological hemopoiesis in various organs.

Acute myeloblastic leukemia occurs in all age groups but commonly in adults and less in children. Acute myeloblastic leukemia is predominantly a disease of adults with two peaks, one at 15 to 20 years of age and another peak after 50 years of age.

Etiology

The reason of the appearance of leukemia is still unknown. Most authors regard hemoblastosis as tumors whose morphological basis are hemopoietic cells of various organs.

Some factors can provoke acute myeloblastic leukemia:

1. chemical concerogenous substances (benzpyrence, benzol);

2. radiaionizing;

1. viruses theory connect the appearance of acute myeloblastic leukemia with DNA or RNA damage, but only animal experimental studies support this point of view;

3. genetic theory: according to this theory, acute leukemia develops due to the congenital or acquired damage to the chromosome structures of low differentiated cells of the hemopoietic organs.

Pathogenesis

A clone theory has been adopted recently, according to which hemoblastosis arises due to primary mutation in one of the hemopoietic cells with its subsequent multiplication and formation of a clone of blast cells.

These cells fail to differentiate properly and proliferate without maturing to the normal nonproliferating stages. The accumulation of this immature, continually dividing cells results to the replacement of the normal hematopoietic precursor cells by these neoplastic cells. This will cause complete bone marrow failure. Expansion and infiltration of tissue and organs with abnormal white blood cells lead to the main clinical features.

Classification

French-American-British Group (FAB)

Ml - undifferentiated

M2 - differentiated

M3 - promyelocytic

M4 - myelomonocytic

M5 - monocytic

M6 - erythroleukemia

M7 - megakaryoblastic

Clinical features

The onset of the disease is in most cases acute or subacute. In some eases the onset disease is gradually with non specific general symptoms: weakness, fatigue, subfebrile temperature, weight loss.

There ate some syndromes of acute leukemia: intoxication, ulcerative necrotic, infections, bleeding, anemia, splenomegaly and hepatomegaly, bone pain, neurological syndrome:

Syndrome of intoxication are as follows: high temperature (remittent or hectic), profuse sweating, chills, pronounced weakness, reduced exercise tolerance, general loss of strength. Fever chills and sweating are explained by the pyrogenic effects of purenes released in great quantity during the decomposition of immature leucocytes.

Ulcerous - necrotic syndrome is characterized pain in the throat, swallowing becomes painful. Ulcerous of the oral mucosa occurs commonly in acute myeloblastic leukemia. There may be infiltration of the gums with swelling and bleeding. Ulcerous and necrotic tonsillitis, gingivitis and stomatitis are quite characteristic of this disease.

Despite the markedly increased production of white blood cells, their function is inadequate. This fact is explained such complications as secondary infections due to the pathogenetic agents: gram negative bacteria, staphylococci and streptococci, viral - herpes simplex and zoster, fungal - Candida, protozoal - pneumocystitis carinii. The infections of skin, mouth, throat, respiratory and urinary tract including septicemia are common usually. Pericarditis and pleuritis arc possible.

Bleeding syndrome: traces of subcutaneous and imracutaneuos hemorrhages can be seen. The lesions vary in size from small pointed hemorrhages (petechiae) to large black and blue spots (ecchymosed) which appear spontaneously or at points of injections. Spontaneous bruises, purpura, bleeding gums and bleeding from venepuncture sites because of thrombocytopenia are common. Occasionally there may be major internal hemorrhage.

Syndrome of anemia is explained by depressed erythropoiesis; increased bleeding; accelerated destruction of red blood cells. The degree of anemia depends of the speed of the development of acute myeloblastic leukemia as well as on iron and folic acid stores. There are general symptoms of anemia: fatigue, dizziness and dyspnea. The mucous membranes and nail beds are pallor.

Lymphadenopathy is rare sign in patients with acute myeloblastic leukemia. Sometimes enlarged cervical and supraclavicular lymph nodes are detected in the superficial areas by palpation. Tenderness of the sternum may be quite pronounced. Blast infiltration of meningeal membranes lead to neurological disorders with clinical features of meningitis.