Megaloblastic anemia an overview sciencedirect topics. Thiamine responsive megaloblastic anemia trma is characterized by a triad of megaloblastic anemia, non. Megaloblastic anemia is an anemia of macrocytic classification that results from inhibition of dna synthesis during red blood cell production. The most common causes are folate vitamin b9 deficiency and cobalamin vitamin b12 deficiency. Folic acid and cobalamin are bgroup vitamins that play an essential role in many cellular processes. Druginduced megaloblastic anemia tion of serine hydroxymethyl transferase. When dna synthesis is impaired, the cell cycle cannot progress from the g2 growth stage to the mitosis m stage. Megaloblastic anemia is a type of anemia which is characterized by morphologically abnormal unusually large and immature red blood cells known as megaloblasts causes of megaloblastic anemia. Learn vocabulary, terms, and more with flashcards, games, and other study tools. This leads to continuing cell growth without division, which presents as macrocytosis. In addition, deficiencies of ascorbic acid, tocopherol, and thiamine may be.
Pdf laboratory testing for cobalamin deficiency in. Mouallem and colleagues nov 2, p 12161 report a patient with megaloblastic anaemia due to vitamin b12 deficiency who presented with anaemia, fever, and splenomegaly. Megaloblastic anemia has several different causes deficiencies of either cobalamin vitamin b12 or folate vitamin b 9 are the two most common causes. Pathophysiology and laboratory diagnosis of pernicious anemia.
It is this crucial role of dihydrofolate reductase in thymidine nucleotide biosynthesis that makes it a target for antineoplastic thera. Laboratory testing for cobalamin deficiency in megaloblastic anemia. Megaloblastic anemia causes macrocytic anemia from ineffective red blood cell production and intramedullary hemolysis. Pdf thiamineresponsive megaloblastic anemia syndrome. Megaloblastic anemia is a type of anemia, a blood disorder in which the number of red blood cells is lower than normal. We were somewhat concerned that, despite no evidence in the report that the patient had severe symptoms from his anaemia, he was treated initially by the transfusion of two units of packed red cells, before the start of vitamin. Megaloblastic anemia can be diagnosed based on characteristic morphologic and laboratory findings. In more than 95% of cases, megaloblastic anemia is a result of folate and vitamin b 12 deficiency. Deficiency in one or both of these vitamins causes megaloblastic anaemia, a disease. What is the etiologic role of genetics in pernicious anemia. Pdf diagnosis and treatment of macrocytic anemias in adults. Megaloblastic anemia is caused by deficiency or impaired utilization of vitamin b12 andor folate, whereas nonmegaloblastic macrocytic anemia is caused by various diseases such as myelodysplastic. Megaloblastic anemias are characterized by the presence of megaloblasts in the bone marrow and macrocytes in the blood.
Other clinical findings have been described in few cases. Megaloblastic anemia may also result from rare inborn errors of metabolism of folate or vitamin b 12. However, other benign and neoplastic diseases need to be considered. If dihy drofolate is not reduced and methylated, the cell is starved of thymidylate, and dna synthesis slows.