Anemia Basics Quiz

Anemia Basics

• Anemia is a clinical condition where the blood's capacity to transport oxygen to tissues is reduced due to a lower than normal hemoglobin concentration or a reduced RBC count.
• In adults, normal hemoglobin levels are 13.0 g/dL for males and 11.5 g/dL for females.
• Anemia can present with various symptoms, including dizziness, headaches, chest pain, paleness, fatigue, and cold skin.

Lecture Objectives

• Diagnose anemia by applying diagnostic steps.
• Explain compensatory mechanisms and clinical presentation of anemia.
• Identify different types of anemia based on underlying mechanisms and RBC indices.
• Identify causes of aplastic anemia and pancytopenia.

Etiological Classification of Anemia

• Anemia due to blood loss:
  • Acute post-hemorrhagic anemia
  • Chronic blood loss
• Anemia due to impaired red blood cell production:
  • Defects in heme synthesis (iron deficiency anemia)
  • Defects in globin synthesis (thalassemic syndromes)
  • Defects in nuclear maturation (vitamin B12/folate deficiency, megaloblastic anemia)
  • Defects in stem cell proliferation/differentiation (aplastic anemia, pure red cell aplasia)
• Anemia due to increased red blood cell destruction (hemolytic anemia)
  • Extrinsic (extracorpuscular) abnormalities
  • Intrinsic (intracorpuscular) abnormalities (details in Table 10.10)

Morphological Classification of Anemia

• Microcytic hypochromic:
  • Reduced mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC).
  • Includes: thalassemia, anemia of chronic disease, iron deficiency anemia, lead poisoning, sideroblastic anemia
• Normocytic normochromic:
  • Normal MCV and MCHC.
• Macrocytic normochromic:
  • Raised MCV, normal MCHC.
  • Includes: vitamin B12 deficiency, folate deficiency, thiamine deficiency
• Other types:
  • High reticulocyte count: sickle cell anemia, hereditary spherocytosis, autoimmune hemolytic anemia, paroxysmal nocturnal hemoglobinuria, enzyme deficiency
  • Low reticulocyte count: renal failure, anemia of chronic disease, myelofibrosis, cancers (metastasis or leukemias)

Diagnostic Approach in Anemia

• History (menstrual bleeding, chronic blood loss, trauma, injury)
• Clinical examination (signs & symptoms)
• Lab investigation:
  • Hemoglobin estimation and complete blood count (CBC)
  • Peripheral blood film examination (variation in size/shape, inadequate hemoglobin formation)
  • Red blood cell indices
  • Leucocyte and platelet count
  • Reticulocyte count
  • Bone marrow examination
• Biochemical tests (serum iron, folate, vitamin B12 levels)

Diagnostic Workout of Anemia

• An algorithm outlining a diagnostic process for various types of anemia.
• Includes considerations for microcytic, normocytic, and macrocytic anemia, along with normal or low/high ferritin.
• Leading to specific diagnoses such as thalassemia, iron deficiency anemia, hemolytic anemia, etc.

Pancytopenia

• Pancytopenia is a condition characterized by a significant reduction in red blood cells, white blood cells, and platelets.

Causes of Pancytopenia

• Aplastic anemia
• Myelodysplastic syndromes
• Hypersplenism
• Megaloblastic anemia
• Paroxysmal nocturnal hemoglobinuria
• Bone marrow infiltrations (hematological or non-hematological malignancies, storage diseases, myelofibrosis)

Bone Marrow Examination

• Provides insights into the cellularity and ratio of different cell types (M:E ratio)
• Examines erythropoiesis, myelopoiesis, megakaryopoiesis, and bone marrow iron stores.

Biochemical Tests

• A table that can be used to define normal ranges of serum ferritin, serum iron, serum transferrin saturation, total plasma iron-binding capacity (TIBC), serum transferrin receptor (TFR), and red cell protoporphyrin in anemia.

Compensatory Mechanisms in Anemia

• The body's response to anemia involves various pathways and hormonal mechanisms to maintain adequate oxygen delivery to tissues.
• Mechanisms to increase oxygen-carrying capacity include increased heart rate, stroke volume, cardiac dilation, peripheral vasodilation, and increase in erythrocytes