Pathogenesis of megaloblastic anemia

Megaloblastic anemia is a form of macrocytic anemia, a blood disorder that happens when your bone marrow produces stem cells that make abnormally large red blood cells. Megaloblastic anemia is a type of vitamin deficiency anemia that happens when you don’t get enough vitamin B12 and/or vitamin B9 (folate). Healthcare providers treat megaloblastic anemia with vitamin B12 and B9 supplements. Overview What is megaloblastic anemia? Megaloblastic anemia is a form of How does megaloblastic anemia affect my body? Your body needs a certain amount of healthy red blood cells to carry oxygen from your lungs to your tissues and back again. Like all blood cells, red blood cells start as stem cells in your bone marrow. Vitamin B12 and vitamin B9 help form red blood cells. Without enough vitamin B12 or vitamin B9, your body produces abnormal cells called megaloblasts. Megaloblasts don’t divide and reproduce like healthy cells, which means there are fewer red blood cells in your bone marrow. The abnormal cells are unusually large, so large they often can’t get out of your bone marrow to move into your bloodstream. And even if they do make their way into your bloodstream, the abnormal cells die earlier than healthy red blood cells. Combined, these factors reduce the number of red blood cells, causing Is megaloblastic anemia a serious illness? Megaloblastic anemia is caused in part by vitamin B12 deficiency. Left untreated, vitamin B12 deficiency can cause neurological issues, including mem...

Abstract MEGALOBLASTIC infants and children has been recognized in much the same circumstances as in adults. Pernicious anemia is exceedingly rare but has been reported as beginning even in infancy. 1 Megaloblastic anemia has occasionally been found in association with steatorrhea 2 and other disorders interfering with the ingestion, absorption or utilization of essential nutrients. 3 These types of megaloblastic anemia are uncommon and occur throughout the period of infancy and childhood. It has become evident that there is a form of megaloblastic anemia which is commoner and occurs predominantly in the first year of life. Although the existence of megaloblastic anemia in infants was verified by bone marrow biopsy at least as early as 1940 by Veeneklaas, 4 the prevalence of this type of anemia in infancy was not fully appreciated until 1946, when the very complete descriptions by Zuelzer and Ogden 5 in America and Amato 6 in Italy • Academic Medicine • Acid Base, Electrolytes, Fluids • Allergy and Clinical Immunology • Anesthesiology • Anticoagulation • Art and Images in Psychiatry • Assisted Reproduction • Bleeding and Transfusion • Cardiology • Caring for the Critically Ill Patient • Challenges in Clinical Electrocardiography • Climate and Health • Clinical Challenge • Clinical Decision Support • Clinical Implications of Basic Neuroscience • Clinical Pharmacy and Pharmacology • Complementary and Alternative Medicine • Consensus Statements • Coronavirus (COVID-19) • Crit...

The myelodysplastic syndrome (MDS) is group of clonal hematopoietic stem cell disorders typified by peripheral cytopenia, dysplastic hematopoietic progenitors, a hypercellular or hypocellular bone marrow, and a high risk of conversion to Acute Myeloid Leukemia (AML) In acute myeloid leukemia (AML), malignant transformation and uncontrolled proliferation of an abnormally differentiated, long-lived myeloid progenitor cell results in high circulating numbers... read more . Symptoms are referable to the specific cell line most affected and may include fatigue, weakness, pallor (secondary to anemia), increased infections and fever (secondary to neutropenia), and increased bleeding and bruising (secondary to thrombocytopenia). Diagnosis is by blood count, peripheral smear, and bone marrow aspiration and biopsy. Treatment with azacitidine or decitabine may help; if acute myeloid leukemia supervenes, it is treated per the usual protocols. Myelodysplastic syndromes are a group of clonal hematopoietic stem cell disorders unified by the presence of distinct mutations of hematopoietic stem cells, most frequently in genes involved in RNA splicing. Myelodysplastic syndromes are characterized by ineffective and dysplastic hematopoiesis and include the following: The etiology of myelodysplastic syndrome is unknown. Risk increases with age due to the acquisition of somatic mutations that can promote clonal expansion and dominance of a particular hematopoietic stem cell, and possibly due to...

ABSTRACT Megaloblastic anemia causes macrocytic anemia from ineffective red blood cell production and intramedullary hemolysis. The most common causes are folate (vitamin B 9) deficiency and cobalamin (vitamin B 12) deficiency. Megaloblastic anemia can be diagnosed based on characteristic morphologic and laboratory findings. However, other benign and neoplastic diseases need to be considered, particularly in severe cases. Therapy involves treating the underlying cause—eg, with vitamin supplementation in cases of deficiency, or with discontinuation of a suspected medication. KEY POINTS • The hallmark of megaloblastic anemia is macrocytic anemia (mean corpuscular volume > 100 fL), often associated with other cytopenias. • Dysplastic features may be present and can be difficult to differentiate from myelodysplastic syndrome. • Megaloblastic anemia is most commonly caused by folate deficiency from dietary deficiency, alcoholism, or malabsorption syndromes or by vitamin By deficiency, usually due to pernicious anemia. • Both vitamin deficiencies cause hematologic signs and symptoms of anemia; vitamin B 12 deficiency also causes neurologic symptoms. • Oral supplementation is available for both vitamin deficiencies; intramuscular vitamin B 12 supplementation should be used in cases involving severe neurologic symptoms or gastric or bowel resection. Not all megaloblastic anemias result from vitamin deficiency, but most do. Determining the underlying cause and initiating prompt tre...

AMA Citation Hoffbrand A. Hoffbrand A Hoffbrand, A. Victor.Megaloblastic Anemias. In: Jameson J, Fauci AS, Kasper DL, Hauser SL, Longo DL, Loscalzo J. Jameson J, & Fauci A.S., & Kasper D.L., & Hauser S.L., & Longo D.L., & Loscalzo J(Eds.), Eds. J. Larry Jameson, et al.eds. Harrison's Principles of Internal Medicine, 20e. McGraw Hill; 2018. Accessed June 16, 2023. https://accessmedicine.mhmedical.com/content.aspx?bookid=2129§ionid=192017242 APA Citation Hoffbrand A. Hoffbrand A Hoffbrand, A. Victor. (2018). Megaloblastic anemias. Jameson J, Fauci AS, Kasper DL, Hauser SL, Longo DL, Loscalzo J. Jameson J, & Fauci A.S., & Kasper D.L., & Hauser S.L., & Longo D.L., & Loscalzo J(Eds.), Eds. J. Larry Jameson, et al. Harrison's Principles of Internal Medicine, 20e. McGraw Hill. https://accessmedicine.mhmedical.com/content.aspx?bookid=2129§ionid=192017242 MLA Citation Hoffbrand A. Hoffbrand A Hoffbrand, A. Victor. "Megaloblastic Anemias." Harrison's Principles of Internal Medicine, 20e Jameson J, Fauci AS, Kasper DL, Hauser SL, Longo DL, Loscalzo J. Jameson J, & Fauci A.S., & Kasper D.L., & Hauser S.L., & Longo D.L., & Loscalzo J(Eds.), Eds. J. Larry Jameson, et al. McGraw Hill, 2018, https://accessmedicine.mhmedical.com/content.aspx?bookid=2129§ionid=192017242. The megaloblastic anemias are a group of disorders characterized by the presence of distinctive morphologic appearances of the developing red cells in the bone marrow. The marrow is usually hypercellular and the...

х All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible. We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies. If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter. Megaloblastic anemia unites a group of acquired and hereditary anemias, a common feature of which is the presence of megaloblasts in the bone marrow. Regardless of the cause, hyperchromic anemia with characteristic changes in the morphology of erythrocytes, erythrocytes of oval form, large (up to 1 2 - 1 4 microns and more) is revealed in patients. There are erythrocytes with basophilic cytoplasmatic location, in many of them the remains of the nucleus are found (Jolly's bodies are the remains of nuclear chromatin, the Keboat rings are the remains of the nuclear envelope that look like a ringlet, Weidenreich dust particles are the remains of nuclear matter). The amount of reticulocytes decreased. Along with anemia, leukoneutro- and thrombocytopenia are possible, typically the appearance of polysigmented neutrophils. In the bone marrow punctate the number of myelokaryocytes is increased, the erythroid germ is hyperplastic, the leukocyte-erythrocyte ratio is 1: 1, 1: 2 (3-4: 1 normally). Cel...