Lecture on Different Types of Anemia

What is Anemia?

• Definition: Low oxygen-carrying capacity, either due to low number or dysfunctional red blood cells (RBCs).
• Indicators: Low hematocrit, low percentage of packed cell volume (PCV) less than 45%.

Types of Anemia

1. Iron Deficiency Anemia

• Symptoms:
  • Shortness of breath (dyspnea)
  • Fatigue
  • Increased workload on the heart
  • Tachycardia
  • Dizziness and potential syncope
• Pathophysiology:
  • Iron is needed for hemoglobin production.
  • Deficiency leads to low heme and dysfunctional hemoglobin.
  • Results in smaller RBCs (microcytic anemia, MCV < 90 fL).
• Causes:
  • Blood loss (ulcers, heavy menstruation, low iron diet).
• Treatment: Iron supplementation, possibly transfusions.

2. Pernicious Anemia (B-12 or Folic Acid Deficiency)

• Role of B-12:
  • Essential for DNA maturation and RBC development.
  • Deficiency leads to large RBCs (macrocytic anemia, MCV > 90 fL).
• Causes:
  • Autoimmune destruction of intrinsic factor (necessary for B-12 absorption).
• Symptoms: Same as general anemia symptoms.
• Treatment: Intramuscular B-12 injections.

3. Hereditary Spherocytosis

• Genetic Defect: Mutations in RBC membrane proteins (spectrin, ankyrin) leading to spherical RBCs (spherocytosis).
• Consequences:
  • RBCs trapped in spleen causing splenomegaly.
  • Symptoms similar to general anemia.
• Diagnosis: Coombs test.

4. G6PDH Deficiency

• Enzyme Deficiency: Lack of glucose-6-phosphate dehydrogenase (G6PDH).
• Pathophysiology:
  • Decreased NADPH leads to inability to neutralize reactive oxygen species.
  • Hemoglobin damage and formation of Heinz bodies.
  • Hemolytic anemia due to less flexible RBCs.

5. Sickle Cell Anemia (HbS)

• Genetic Mutation: Missense mutation replacing glutamic acid with valine in β-globin chain.
• Consequences:
  • Hemoglobin polymerizes under low oxygen, causing RBCs to sickle.
  • Leads to vaso-occlusive crises.
• Symptoms: Priapism, splenomegaly.
• Treatment: Oxygen therapy, pain relievers, fluids, hydroxyurea (increases fetal hemoglobin).

6. Hemorrhagic Anemia

• Cause: Blood loss from trauma, ulcers, or aneurysms.
• Symptoms: Standard anemia symptoms due to decreased RBCs.
• Treatment: Blood transfusions, fluid replacement, surgical intervention for bleeding source.

7. Aplastic Anemia

• Pathophysiology: Bone marrow damage affects myeloid stem cell lines.
• Consequences: Pancytopenia (low RBCs, WBCs, platelets).
• Symptoms:
  • Increased infection incidence (due to low WBCs).
  • Bruising/bleeding (due to low platelets).
• Causes: Drugs, radiation, viruses. _ Treatment: Bone marrow transplant, antibiotic therapy, transfusions.

8. Thalassemia

• Genetic Condition: Faulty or missing globin chains (α or β).
• Types: Alpha thalassemia, Beta thalassemia.
• Symptoms: Microcytic anemia (MCV < 90 fL), standard anemia symptoms.
• Treatment: Regular transfusions, iron supplements, oxygen therapy, possibly bone stem cell transplant.

Summary

• Anemia can be categorized by underlying cause: deficiency, genetic mutations, blood loss, bone marrow damage, etc.
• Most anemias present with common symptoms like fatigue, shortness of breath, and dizziness, but specific types have unique features and treatments.