|Series||Modern medical monographs,, 18|
|LC Classifications||RC641.7.M4 H4|
|The Physical Object|
|Pagination||vi, 162 p.|
|Number of Pages||162|
|LC Control Number||59010562|
The emphasis on diagnosis and the fact that this book is addressed mainly to the general practitioner are its most important features. The six chapters deal with the concept of megaloblastosis, therapeutic preparations, Addisonian pernicious anemia, non-Addisonian megaloblastic anemia, diagnosis, and the etiology of the megaloblastic anemias. The main cause of megaloblastic anemias is deficiency of either cobalamin (vitamin B 12) or folic acid, vitamins that are essential for DNA replication and repair. In addition, chemotherapeutic drugs that inhibit DNA synthesis can result in findings similar to those seen in cobalamin or folate deficiency. Vitamin B 12 and folate deficiencies are major causes of megaloblastic anemia. Causes of B 12 deficiency include pernicious anemia, gastric surgery, intestinal disorders, dietary deficiency, and inherited disorders of B 12 transport or absorption. The prevalence of folate deficiency has decreased because of folate fortification, but deficiency still occurs from malabsorption and increased demand. Cellular characteristics of Megaloblastic Anemia: 1. A characteristic finding in bone marrow smears for megaloblastic anemia would the appearance of nuclear-cytoplasmic (N:C) asynchrony in all cell lines. 1 N:C asynchrony describes the inability of the cell’s chromatin to mature normally giving the nucleus a more immature, more fine, looser.
Megaloblastic anemias are a group of disorders characterized by reduced DNA synthesis (not just in red cell series) associated with pathognomonic morphological changes. When DNA synthesis is impaired, the cell cycle cannot progress from the G2 growth stage to the mitosis (M) stage. 1. Megaloblastic Anaemias Dr. Raghav Kakar M.D. Paeds 2. Definition Megaloblastic anemia is a general term used to describe a group of anemias caused by impaired DNA synthesis. It is characterized by abnormal findings in peripheral blood smear (macroovalocytes) and bone marrow samples (megaloblastic hyperplasia). Megaloblastic anemia is a condition in which the bone marrow produces unusually large, structurally abnormal, immature red blood cells (megaloblasts). Bone marrow, the soft spongy material found inside certain bones, produces the main blood cells of the body -red cells, white cells, and platelets. Anemia is a condition of decrease in number of circulating red blood cells (and hence hemoglobin) below a normal range for age and sex of the individual, resulting in decreased oxygen supply to tissues. Megaloblastic anemia is a type of macrocytic anemia, which is characterized by defective DNA synthesis and presence of distinct megaloblasts in the bone marrow.
Macrocytic anemia: peripheral blood smear to differentiate megaloblastic anemia from nonmegaloblastic anemia. Megaloblastic anemia: serum B 12 and folate levels and, if necessary, serum homocysteine and methylmalonic acid levels to identify vitamin B 12 deficiency and/or folate deficiency. Megaloblastic anemia is the second most common nutritional anemia in pregnancy. Folate and vitamin B 12 requirements increase during pregnancy because both are involved in nucleic acid formation in the developing fetus. Because of the increased risk of neural tube defects in women who are deficient in folate (Chapter 18), prenatal. Pernicious anemia (the best known cause): autoimmune destruction of gastric parietal cells → failure in secretion of intrinsic factor (IF), in the absence of which cobalamin is not absorbed Pernicious anemia is diagnosed in about 1% of people older than 60 years, with the incidence slightly higher in females. H2 antagonists: inhibit IF secretion. Types of Anemia 1.) Hypochromic, microcytic: Iron Deficiency Thalassemia syndromes Sideroblastic anemia Transferrin deficiency 2.) Macrocytic: Megaloblastic Anemias (Folic acid/ B 12 deficiencies) Liver Disease Reticulocytosis Normal newborn Bone marrow failure syndromes Drugs (AZT, Trimethoprin sulfate).