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Pathology - Megaloblastic anemias
Definition: A decrease in hemoglobin concentration resulting from compromised erythroid DNA synthesis. The majority of instances pertain to deficiencies in either vitamin B12 or folate.
Aetiology
Autoimmune gastritis is the predominant cause of vitamin B12 deficiency. Megaloblastic anemia resulting from autoimmune gastritis is referred to as pernicious anemia. This impacts around 1 in 1000 individuals, with a feminine predisposition
. • An inadequate diet is the predominant cause of folate deficiency. The primary dietary sources of folate are leafy green vegetables. Deficiency is commonly observed in the elderly and individuals with alcohol dependence.
Pathogenesis Vitamin B12 and folate are essential for the conversion of deoxyuridine monophosphate into deoxythymidine monophosphate, a chemical necessary for DNA synthesis. • Developing red blood cells are unable of division due to insufficient DNA synthesis required for the formation of two nuclei. • Consequently, they become stalled in their maturation as giant immature cells (megaloblasts), a significant number of which perish in the bone marrow. •
Certain megaloblasts persist and differentiate into unusually large erythrocytes (macrocytes), which are subsequently discharged into the bloodstream.
Presentation • Symptoms associated with severe anemia. Mild jaundice may occur as a result of hemolysis. Vitamin B12 deficiency may lead to neurological manifestations, such as cognitive impairment, peripheral neuropathy, and subacute combined degeneration of the spinal cord.
Complete blood count • Hemoglobin concentration is generally exceedingly low, nearing only 2 g/dL. • MCV is generally elevated. Peripheral blood smear • Notable anisocytosis and poikilocytosis characterized by big oval macrocytes. Nucleated red blood cells may be observed. • Hypersegmented neutrophils. The bone marrow is hypercellular, with numerous immature big erythroid blasts (megaloblasts) and massive metamyelocytes.
Definition: A decrease in hemoglobin concentration resulting from compromised erythroid DNA synthesis. The majority of instances pertain to deficiencies in either vitamin B12 or folate.
Aetiology
Autoimmune gastritis is the predominant cause of vitamin B12 deficiency. Megaloblastic anemia resulting from autoimmune gastritis is referred to as pernicious anemia. This impacts around 1 in 1000 individuals, with a feminine predisposition
. • An inadequate diet is the predominant cause of folate deficiency. The primary dietary sources of folate are leafy green vegetables. Deficiency is commonly observed in the elderly and individuals with alcohol dependence.
Pathogenesis Vitamin B12 and folate are essential for the conversion of deoxyuridine monophosphate into deoxythymidine monophosphate, a chemical necessary for DNA synthesis. • Developing red blood cells are unable of division due to insufficient DNA synthesis required for the formation of two nuclei. • Consequently, they become stalled in their maturation as giant immature cells (megaloblasts), a significant number of which perish in the bone marrow. •
Certain megaloblasts persist and differentiate into unusually large erythrocytes (macrocytes), which are subsequently discharged into the bloodstream.
Presentation • Symptoms associated with severe anemia. Mild jaundice may occur as a result of hemolysis. Vitamin B12 deficiency may lead to neurological manifestations, such as cognitive impairment, peripheral neuropathy, and subacute combined degeneration of the spinal cord.
Complete blood count • Hemoglobin concentration is generally exceedingly low, nearing only 2 g/dL. • MCV is generally elevated. Peripheral blood smear • Notable anisocytosis and poikilocytosis characterized by big oval macrocytes. Nucleated red blood cells may be observed. • Hypersegmented neutrophils. The bone marrow is hypercellular, with numerous immature big erythroid blasts (megaloblasts) and massive metamyelocytes.
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