CVR Haematology

Haematology

• Haematology is the study of blood
• Adults have approximately 7% of their body weight as blood

Haematopoiesis and Haemostasis

• Blood is comprised of plasma (55%) and cellular components (45%)
• Haematopoiesis is the process where blood cells are created
• It begins in the yolk sac, spleen, and liver, and later in the bone marrow of the cranium, pelvis, ribs, and vertebra in adults.
• Bone marrow is a supportive environment for stem cells to grow
• Cells found in the niche include macrophages, fibroblasts, and fat cells
• Key growth factors include Colony-Stimulating Factors (CSFs), such as Multi-CSF (IL-3), and GM-CSF (Granulocyte macrophage), EPO (Erythropoietin), and TPO (Thrombopoietin) for different cell types.

Blood Cell Types

• Different types of blood cells have specific functions
  • Red blood cells: oxygen and carbon dioxide transport
  • Platelets: haemostasis (blood clotting)
  • White blood cells: protection against bacteria, viruses, fungi, and parasites.

Haematopoiesis (More detail)

• Myeloid lineage cells include neutrophils and monocytes
• Lymphoid lineage cells include lymphocytes
• Abnormalities in blood cell counts (e.g., anaemia, leukopenia, leukocytosis, thrombocytopenia, thrombocytosis) can indicate various health conditions.

Examinations

• Bone marrow aspiration involves extracting a small sample of bone marrow tissue for analysis.
• Bone marrow biopsy is used to obtain a larger sample when aspiration is not possible
• Healthy samples show a mix of cells at various development stages, with myeloid cells being more dominant than lymphoid.

Granulopoiesis

• Granulocytes (neutrophils, eosinophils, basophils) develop and differentiate in the bone marrow.
• Mature granulocytes have distinct granules in their cytoplasm

Thrombopoiesis

• Platelets are produced by megakaryocytes
• Platelets are essential for blood clotting (haemostasis)
• The process involves nuclear and cytoplasmic growth in megakaryocytes; cytoplasm then splitting into numerous platelets.

Erythropoiesis

• Erythropoietin (EPO) stimulates red blood cell production
• Iron and other essential nutrients are crucial for red blood cell production,
• Red blood cells have a lifespan of approximately 120 days.
• Aged or damaged red blood cells are broken down in the liver and spleen.

Full Blood Count (FBC)

• FBC measures different components of blood, including red and white blood cells, platelets
• Important parameters: RBC, WBC, platelets, hemoglobin Abnormalities can indicate various clinical conditions

Haemostasis

• A process of stopping bleeding
• It involves platelets forming a temporary plug, followed by fibrin making the plug stronger
• The process is crucial for preventing excessive blood loss

Coagulation and Regulation

• Clotting factors activated via the intrinsic or extrinsic pathways.
• The coagulation cascade activates special proteins called clotting factors.
• Several processes regulate blood clotting to avoid excessive clotting (e.g., healthy blood vessels release prostacyclin and nitric oxide).

Blood Disorders

• Thrombocytopenia: Decreased platelet count, causing increased bleeding tendencies
• Thrombosis: Formation of a blood clot inside a blood vessel
• Disseminated Intravascular Coagulation (DIC): A condition where excessive clotting throughout the body occurs.

Tests

• Various tests (e.g., bleeding time, prothrombin time, activated partial thromboplastin time, thrombin time) assess blood clotting abilities.

Haemophilia

• Genetic disorder affecting blood clotting factors.