1- MICROCYTIC ANEMIA

• Iron deficiency anemia


  Most common cause of anemia worldwide
• Types of iron


  • Heme iron (ferrous, Fe2+, from meat, better absorbed)
  • Non-heme iron (ferric, Fe3+, from vegetables & cereal, reduced to Fe2+ by brush border ferrireductase enzyme)
• Iron transport and storage

  Transported in plasma bound to transferrin, stored as ferritin & hemosiderin in hepatocytes, skeletal muscle, and macrophages
• Causes of iron deficiency anemia

  • Blood loss (most common cause, from GI or menses, hookworm)
  • Increased demand (growth or pregnancy)
  • Poor intake
  • Decreased absorption (gastrectomy/small bowel disease)
• Signs and symptoms of iron deficiency anemia

  • Anemia (fatigue, pallor, SOB, tachycardia)
  • Brittle hair and nails
  • Atrophic glossitis, angular stomatitis
• Investigations for iron deficiency anemia

  • CBC (↓Hb, microcytic ↓MCV, hypochromic ↓MCH, ↓Retics, ↑RDW, reactive thrombocytosis)
  • Blood film (small hypochromic RBCs, anisocytosis, poikilocytosis)
  • Iron studies (↓Iron, ↓ferritin, ↓transferrin saturation, ↑TIBC, ↑Transferrin receptor #)
  • Further GI investigations to find reason for blood loss
• Treatment for iron deficiency anemia

  • Treat underlying cause
  • Oral iron supplements (ferrous sulphate/gluconate), 3-6 months
  • Monitor response by increase in retics followed by ↑ in Hb 10g/L per week until normal
  • IV iron (if unable to tolerate side effects, or have a disease that affects absorption, or to increase iron quickly before surgery)
• Sideroblastic anemia


  Abnormality in RBC iron metabolism (heme synthesis) leading to refractory anemia
• Causes of sideroblastic anemia

  • Hereditary
  • Acquired (myelodysplasia, alcohol, lead toxicity, drugs: isoniazid, chloramphenicol, Vitamin B6 deficiency)
• Sideroblastic anemia


  • Blood film: hypochromic cells

  Bone marrow: ringed sideroblasts (erythroblasts with iron deposited in mitochondria)

  Iron studies: ↑ iron & ferritin, N/↑ TIBC saturation
• Treatment for sideroblastic anemia

  Remove causative agent, some respond to pyridoxine (vitamin B6)
• Thalassemia is discussed under "Hemolytic anemia"