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Anemia in myelofitis: causes, symptoms, diagnosis, treatment
Last reviewed: 23.04.2024
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Anemia in myelofthisis is normochromic-normocytic and develops when infiltration or replacement of the normal bone marrow space by non -hematopoietic or abnormal cells. The causes of anemia are tumors, granulomatous diseases and diseases of lipid accumulation. Often there is bone marrow fibrosis. Splenomegaly may develop. Typical changes in peripheral blood are anisocytosis, poikilocytosis, the presence of erythrocyte and leukocyte progenitors. The diagnosis usually requires trepanobiopsy. Treatment consists in maintenance therapy and elimination of the underlying disease.
Descriptive terminology used in this type of anemia can be confusing. Myelofibrosis, in which the replacement of bone marrow by a fibrous tissue, can be idiopathic (primary) or secondary. True myelofibrosis is an anomaly of the stem cell, in which fibrosis is secondary to other hematopoietic events. Myelosclerosis is a new formation of bone tissue, which is sometimes accompanied by myelofibrosis. Myeloid metaplasia reflects the presence of extramedullary hemopoiesis in the liver, spleen, or lymph nodes and may be accompanied by myelophthisis due to another cause. The old term "idiopathic myeloid metaplasia" indicates primary myelofibrosis with or without myeloid metaplasia.
[Causes of the anemia in myelophthisis
The most common cause is the replacement of bone marrow metastases of a malignant tumor (more often the breast or prostate, less often the kidneys, lungs, adrenals or thyroid gland); extramedullary hemopoiesis is not characteristic. Other causes include myeloproliferative diseases (especially in later stages or progressive erythremia), granulomatous diseases and accumulation diseases (lipids). Myelofibrosis can occur in all of the cases listed above. In children, a rare cause may be Apberus-Schoenberg disease.
Myeloid metaplasia can lead to splenomegaly, especially in patients with accumulation diseases. Hepatosplenomegaly rarely combines with myelofibrosis due to malignant tumors.
Risk factors
Factors contributing to the reduction of erythrocyte production may be a decrease in the number of functioning hematopoietic cells, metabolic disorders associated with the underlying disease, and in some cases erythrophagocytosis. Extramedullary hemopoiesis, or destruction of the medullary cavity, causes the release of young cells. Abnormal forms of red blood cells are often the result of increased destruction of erythrocytes.
Symptoms of the anemia in myelophthisis
In severe cases, symptoms of anemia and underlying disease manifest themselves. Massive splenomegaly can cause increased pressure in the abdominal cavity, rapid saturation and pain in the left upper quadrant of the abdomen. There may be hepatomegaly.
Myelofthisis is suspected in patients with normocytic anemia, especially in the presence of splenomegaly if there is a potential underlying disease. If suspected, a smear of peripheral blood should be studied, since the presence of immature myeloid cells and nucleated erythrocytes, such as normoblasts, presupposes the presence of myelophthosis. Anemia is usually of medium intensity, normocytic, but can tend to macrocytosis. The morphology of erythrocytes can show extreme variants in size and shape (anisocytosis and poikilocytosis). The number of leukocytes can vary. The number of platelets is often low, there are giant, fancy platelets. Often there is reticulocytosis, which can be caused by the release of reticulocytes from the bone marrow or extramedullary zones and always indicates the regeneration of hematopoiesis.
Diagnostics of the anemia in myelophthisis
Although the study of peripheral blood can be informative, a bone marrow examination is necessary for the diagnosis. Indications for puncture may serve as leukoerythroblast blood changes and unexplained splenomegaly. It is often difficult to obtain bone marrow aspirate, usually trepanobiopsy is required. The changes detected depend on the underlying disease. Erythropoiesis is normal or in some cases reinforced. However, the lifespan of erythrocytes is often reduced. In the spleen or liver, foci of hemopoiesis can be detected.
Radiography of the bones of the skeleton can reveal bone changes (myelosclerosis), characteristic of long-term myelofibrosis, or other bone disorders (osteoblastic or lytic foci in the bones) that suggest the cause of anemia.
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Treatment of the anemia in myelophthisis
Treatment of the underlying disease. In idiopathic cases, maintenance therapy is provided. Erythropoietin (from 20,000 to 40,000 units subcutaneously once or twice a week), glucocorticoids (for example, prednisolone 10 to 30 mg orally daily) can be used, however, the answer is usually not significant. Hydroxyurea (500 mg orally daily or every other day) reduces the size of the spleen and leads to the normalization of red cell levels in many patients, but it takes 6 to 12 months for treatment to respond. Thalidomide (50 to 100 mg orally daily in the evening) can give a mild response.