Meabolastic Anemia

Definition and Causes of Megaloblastic Anemia

• Megaloblastic anemia is a type of macrocytic anemia that results from impaired DNA synthesis.
• It can be caused by:
  • Vitamin B12 deficiency
  • Folic acid deficiency
  • Congenital enzyme defects
  • Acquired DNA synthesis defects (e.g., hydroxyurea)

Pernicious Anemia

• Caused by autoimmune attack on the gastric mucosa, leading to atrophy of the stomach.
• Characterized by achlorhydria and absent or low secretion of Intrinsic Factor (IF).
• More common in females (1.6:1) and typically occurs at around 60 years of age.
• May be associated with autoimmune diseases, such as autoimmune polyendocrine syndrome.
• Common in northern Europeans and tends to run in families.
• Increases the risk of stomach carcinoma.

Clinical Features of Megaloblastic Anemia

• Mild jaundice (lemon-yellow tint) due to excess hemoglobin breakdown from ineffective erythropoiesis.
• Glossitis (beefy-red, sore tongue) and angular stomatitis due to epithelial abnormality.
• Malabsorption symptoms, such as weight loss, may be present.
• Purpura may occur due to thrombocytopenia.

Laboratory Findings

• Macrocytic anemia (MCV > 98 fL) with oval-shaped macrocytes.
• Low reticulocyte count.
• Moderate reduction of total white cell and platelet counts, especially in severely anemic patients.
• Hypersegmented neutrophil nuclei (with six or more lobes) in some cases.
• Hypercellular bone marrow with large erythroblasts showing failure of nuclear maturation.

This quiz covers the definition and causes of meabolastic anemia, including deficiencies in vitamin B12 and folic acid, congenital enzyme defects, and acquired DNA defects. It also touches on pernicious anemia and its relation to autoimmune attacks on the gastric mucosa.