Anemia

Definition of Anemia

• Anemia is a condition with decreased red blood cells (RBCs) or hemoglobin (Hb), reducing oxygen-carrying capacity and causing fatigue, weakness, and dyspnea.

Types of Anemia

1. Based on RBC Size (MCV):

   • Microcytic (MCV < 80 fL): Iron deficiency, thalassemia, sideroblastic anemia.
   • Normocytic (MCV 80–100 fL): Acute blood loss, chronic disease, hemolysis.
   • Macrocytic (MCV > 100 fL): Vitamin B12/folate deficiency, alcoholism, liver disease.

2. Based on Pathophysiology:

   • Iron Deficiency: Low iron levels, most common type.
   • Megaloblastic: Impaired DNA synthesis (B12/folate deficiency).
   • Hemolytic: Premature RBC destruction (autoimmune, hereditary).
   • Aplastic: Bone marrow failure (pancytopenia).
   • Chronic Disease: Linked to inflammation or cancer.
   • Sickle Cell: Genetic, abnormal HbS causing sickled RBCs.
   • Thalassemia: Genetic, defective hemoglobin synthesis.

Causes

1. Blood Loss:

   • Acute (trauma, surgery).
   • Chronic (menorrhagia, GI bleeding).

2. Reduced RBC Production:

   • Nutritional deficiencies (iron, B12, folate).
   • Bone marrow failure (aplastic anemia, leukemia).
   • Chronic diseases (kidney disease).

3. Increased RBC Destruction (Hemolysis):

   • Autoimmune diseases, infections, genetic disorders.

Symptoms

• Fatigue, weakness, pallor.
• Dyspnea, dizziness, palpitations.
• Cold extremities, headaches, chest pain (severe cases).
• Restless legs syndrome (iron deficiency).

Diagnosis

1. Blood Tests:

   • CBC: Low Hb, Hct, and MCV.
   • Reticulocyte Count: Bone marrow activity.
   • Iron Studies: Serum iron, ferritin, TIBC.
   • Vitamin Levels: B12, folate.
   • Hemolysis Markers: LDH, bilirubin, haptoglobin.

2. Specialized Tests:

   • Bone Marrow Biopsy: Aplastic anemia.
   • Electrophoresis: Sickle cell, thalassemia.
   • Coombs Test: Autoimmune hemolysis.

Treatment

1. Nutritional Deficiencies:

   • Iron Deficiency: Oral/IV iron, diet changes.
   • B12 Deficiency: Oral/injections.
   • Folate Deficiency: Oral supplements.

2. Blood Transfusions:

   • Severe anemia (Hb < 7–8 g/dL).

3. Underlying Causes:

   • Chronic kidney disease: Erythropoietin therapy.
   • Aplastic anemia: Immunosuppressants or bone marrow transplant.
   • Hemolytic anemia: Steroids, immunosuppressants, splenectomy.

4. Genetic Disorders:

   • Sickle Cell Disease: Hydroxyurea, bone marrow transplant.
   • Thalassemia: Blood transfusions, iron chelation.

Complications

• Severe Fatigue: Affects quality of life.
• Heart Problems: Tachycardia, heart failure.
• Growth Delay: In children.
• Pregnancy Risks: Preterm birth, low birth weight.
• Organ Damage: Due to prolonged hypoxia.

Prognosis

• Mild Cases: Often reversible.
• Severe Cases: May need long-term monitoring.
• Genetic Disorders: Require lifelong care.

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