Method of conducting myelogram (red bone marrow examination)

To study the red bone marrow, puncture the sternum or iliac bone, from the punctate prepare smears for cytological analysis. When aspiration of the bone marrow there is always a drop of blood, the more the more the aspirate is received. The punctate is usually diluted peripheral blood by no more than 2.5 times. Symptoms of a greater degree of bone marrow dilatation by peripheral blood are as follows:

• Poverty of punctate cell elements.
• Absence of megakaryocytes.
• A sharp increase in the leuko-, erythroblastic ratio (at a ratio of 20: 1 and above, the punctate study is not carried out).
• Decrease in the index of maturation of neutrophils to 0.4-0.2.
• Approximation of the relative content of segmented neutrophils and / or lymphocytes to that of peripheral blood.

In the study of red bone marrow, the percentage of bone marrow elements is counted, and the absolute content of myelokaryocytes and megakaryocytes is determined.

• Myelokaryocytes. The decrease in the content of myelocaryocytes is observed in hypoplastic processes of various etiologies, effects on the human body of ionizing radiation, certain chemicals and drugs, etc. Particularly sharply the number of nuclear elements decreases during aplastic processes. With the development of myelofibrosis, myelosclerosis, marrow punctate is meager and the number of nuclear elements in it is also reduced. If there is syncytial connection between the bone marrow elements (in particular, with myeloma disease), the marrow punctate is difficult to obtain, therefore the content of nuclear elements in a punctate may not correspond to the true number of myelokaryocytes in the bone marrow. High content of myelokaryocytes is observed in leukemia, vitamin B _12- deficiency anemia, hemolytic and posthemorrhagic anemia, that is, with diseases accompanied by bone marrow hyperplasia.
• Megakaryocytes and megakaryoblasts are detected in small amounts, they are located around the periphery of the drug, determining their percentage in the myelogram does not reflect the true position, so they are not counted. Typically, only an indicative, subjective assessment of the relative shift in the direction of younger or mature forms is carried out. An increase in the number of megakaryocytes and megakaryoblasts can cause myeloproliferative processes and metastasis of malignant tumors in the bone marrow (especially in stomach cancer). The content of megakaryocytes also increases with idiopathic autoimmune thrombocytopenia, radiation sickness during the recovery period, chronic myelogenous leukemia. The decrease in the number of megakaryocytes and megakaryoblasts (thrombocytopenia) can cause hypoplastic and aplastic processes, in particular, for radiation sickness, immune and autoimmune processes, metastases of malignant tumors (rarely). The content of megakaryocytes also decreases with acute leukemia, in _12- deficiency anemia, myeloma, systemic lupus erythematosus.
• Blastic cells: an increase in their number with the appearance of polymorphous ugly forms against the background of cellular or hypercellular red bone marrow is characteristic of acute and chronic leukemia.
• Megaloblasts and megalocytes of different generations, large neutrophilic myelocytes, metamyelocytes, hypersegmented neutrophils are characteristic for vitamin B ₁₂ deficiency and folic acid deficiency anemia.
• Myeloid elements: an increase in the number of their mature and immature forms (reactive bone marrow) causes intoxication, acute inflammation, purulent infections, shock, acute blood loss, tuberculosis, malignant neoplasms. Promyelocytic-myelocyte marrow with a decrease in the number of mature granulocytes against the background of a cellular or hypercellular reaction can cause myelotoxic and immune processes. A sharp decrease in the content of granulocytes against the background of a decrease in myelocaryocytes is characteristic of agranulocytosis.
• Eosinophilia of the bone marrow is possible with allergies, helminthic invasions, malignant neoplasms, acute and chronic myeloid leukemias, and infectious diseases.
• Monocytic cells: an increase in their number is detected in acute and chronic monocytic leukemias, infectious mononucleosis, chronic infections, malignant neoplasms.
• Atypical mononuclears: an increase in their number against the background of a decrease in mature myelocaryocytes can cause viral infections (infectious mononucleosis, adenovirus, influenza, viral hepatitis, rubella, measles, etc.).
• Lymphoid elements: an increase in their number, the appearance of holonuclear forms (the shadow of Humprecht) with increasing cellularity of the red bone marrow may cause lymphoproliferative diseases (chronic lymphocytic leukemia, Waldenström macroglobulinemia, lymphosarcoma).
• Plasma cells: an increase in their number with the advent of polymorphism, binuclear cells, change in the color of the cytoplasm can cause plasmacytomas (plasmoblastoma, as well as reactive states).
• Erythrocaryocytes: an increase in their number without disturbance of maturation is observed with erythremia. An increase in the content of erythrocaryocytes and a decrease in the leucoerythropy ratio can cause posthemorrhagic anemia and most hemolytic anemias. Reduction of the content of erythrocaryocytes with a decrease in the total number of myelocaryocytes and a small (relative) increase in blast cells, lymphocytes, and plasmocytes causes hypoaplastic processes.
• Cancer cells and their complexes are detected with metastases of malignant tumors.

To assess the myelogram, it is important not so much to determine the number of bone marrow elements and their percentage as their mutual relationship. The composition of the myelogram should be judged by the specially calculated bone marrow indices characterizing these relationships.

• The erythrocaryocyte maturation index characterizes the state of the erythroid germ, it is the ratio of the percentage of normoblasts containing hemoglobin (i.e., polychromatophilic and oxyphilic) to the total percentage of all normoblasts. The decrease in this index reflects a delay in hemoglobinization, which is observed with iron deficiency and sometimes with hypoplastic anemia.
• The neutrophil maturation index characterizes the state of the granulocyte germ. It is equal to the ratio of the percentage of young elements of the granular series (promyelocytes, myelocytes and metamyelocytes) to the percentage content of mature granulocytes (rod and segmented). An increase in this index with a cell-rich red bone marrow indicates a delay in the maturation of neutrophils, in the case of bone marrow-poor cells, the increased yield of mature cells from the bone marrow and the depletion of the granulocyte reserve. An increase in the neutrophil maturation index is observed in myeloleukemia, leukemoid reactions of the myeloid type, some forms of agranulocytosis; its decrease - with delayed maturation at the mature granulocyte stage or delay in their washout (with hypersplenism, some infectious and purulent processes).
• The leycoerythroblastic ratio is the ratio of the sum of the percentage of all elements of the granulocyte germ to the sum of the percentage of all elements of the erythroid bone marrow. Normally, this ratio is 2: 1-4: 1, that is, in normal bone marrow the number of white cells is 2-4 times higher than the number of red cells. An increase in the index with high cellularity of the red bone marrow (more than 150 × 10 ⁹ / l) indicates hyperplasia of the leukocyte germ (chronic leukemia); at a low cellularity (less than 80 × 10 ⁹ / l) - about reduction of red sprout (aplastic anemia) or a large admixture of peripheral blood. Reduction of the index with high cellularity of the red bone marrow indicates hyperplasia of red sprout (hemolytic anemia), at low cellularity - about the predominant reduction of granulocyte germ (agranulocytosis). The leycoerythroblastic ratio decreases with hemolytic, iron deficient, posthemorrhagic, B ₁₂ deficiency anemia, increases with leukemia and, sometimes, with the inhibition of the erythroid sprout in patients with hypoplastic anemia.

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