Introduction to Haematology

Introduction to Haematology

• Haematology is the branch of medicine focused on blood, blood-forming tissues, and blood diseases.
• It studies blood cells (red blood cells, white blood cells, platelets), blood proteins, clotting, and disorders.
• Blood is a vital fluid connective tissue, transporting oxygen, nutrients, hormones, and waste products.
• Blood cells—red blood cells, white blood cells, and platelets— originate in bone marrow and maintain homeostasis.

Blood Cell Types and Their Functions

• Red Blood Cells (Erythrocytes): Primary function is oxygen transport.
  • Contain hemoglobin, binding oxygen.
  • Deliver oxygen to body tissues.
  • Biconcave shape maximizes surface area for gas exchange.
• White Blood Cells (Leukocytes): Crucial for the immune system.
  • Defend against infection and disease.
  • Types include lymphocytes, neutrophils, monocytes, eosinophils, and basophils, each with specific roles.
• Platelets (Thrombocytes): Essential for blood clotting.
  • Initiate clot formation to stop bleeding from damaged vessels.
  • Activated platelets adhere to damaged vessels and release clotting factors.

Blood Formation

• Hematopoiesis: Blood cell formation process.
  • Primarily in bone marrow, but other organs (spleen, lymph nodes) contribute.
  • Bone marrow has hematopoietic stem cells, creating all blood cell types.
  • Growth factors and signaling pathways regulate hematopoiesis.

Blood Disorders

• Anemia: Deficiency in red blood cells or hemoglobin.
  • Symptoms: fatigue, weakness, shortness of breath.
  • Causes: iron deficiency, vitamin B12 deficiency, genetic disorders.
• Leukemia: Cancer of blood or bone marrow.
  • Uncontrolled proliferation of abnormal white blood cells.
  • Different types, each with specific characteristics.
• Thrombocytopenia: Low platelet count.
  • Increased risk of bleeding.
• Coagulation Disorders: Problems with blood clotting.
  • Inherited or acquired, causing bleeding or clotting issues.
  • Examples: Hemophilia, Disseminated Intravascular Coagulation (DIC).

Diagnostic Tools in Haematology

• Blood tests diagnose and monitor blood disorders.
  • Complete Blood Count (CBC): Measures red blood cells, white blood cells, and platelets.
  • Blood smear: Microscopic analysis of blood cell morphology. Detects abnormal cell size and shape.
  • Blood chemistry: Measures substances (electrolytes, proteins, glucose) to identify underlying conditions.
  • Coagulation studies: Evaluate blood clotting mechanisms for bleeding or clotting disorders.
• Bone marrow aspiration and biopsy assess bone marrow function and diagnose certain blood disorders.

Haematological Assessments

• Clinical Examination: Physical signs (pallor, petechiae, lymphadenopathy) hint at potential haematological problems.
• History Taking: Patient history is critical for identifying risk factors and symptoms like fatigue, unusual bruising, bleeding, or infections.

Blood Transfusions

• Blood transfusions support patients with low blood counts or blood loss.
• Blood is screened and matched to prevent transfusion reactions.
• Transfusions involve components like packed red blood cells, platelets, and fresh frozen plasma, as needed.