Hematology

Hematology (also spelt haematology in British English) represents a critical specialization within the broader fields of internal medicine and pediatrics, focusing specifically on the study of blood, blood-forming organs, and a spectrum of blood-related diseases. It encompasses the comprehensive investigation of blood diseases' etiology (causes), diagnosis, treatment, prognosis (outlook), and prevention.

A hematologist analyzing blood sample under a microscope

Understanding Blood Diseases

Blood diseases or hematological disorders, manifest when there's a disruption in the production of blood or any of its critical components, such as blood cells, hemoglobin, blood proteins, and coagulation mechanisms. These disruptions can significantly impact the body's capacity to transport oxygen, clot blood, fight infections, and maintain overall health.

The Role of Hematologists

Hematologists are highly specialized medical doctors whose practice is dedicated to the field of hematology. They perform a wide range of tasks, from overseeing the hematology laboratory's operations and scrutinizing blood films and bone marrow slides under the microscope, to interpreting diverse hematology test results and managing the care of in-patients and out-patients.

Hematologists often develop further specializations or specific interests in particular areas, including:

• Treatment of bleeding disorders such as hemophilia
• Management of hematological malignancies like lymphoma and leukemia (also known as onco-hematology)
• Treatment of hemoglobinopathies, abnormalities in the structure of hemoglobin
• Research and clinical work in the field of blood transfusion and the operation of a blood bank

Hematology as basic medical science

• Blood
  • Venous blood
  • Venipuncture
  • Hemopoiesis
  • Blood tests
  • Cord blood
• Red blood cells
  • Erythropoiesis
  • Erythropoietin
  • Iron metabolism
  • Hemoglobin
  • Glycolysis
  • Pentose phosphate pathway
• Reticuloendothelial system
  • Bone marrow
  • Spleen
  • Liver
• Lymphatic system
• Blood transfusion
  • Blood plasma
  • Blood bank
  • Blood donors
  • Blood groups
• Haemostasis
  • Coagulation
  • Vitamin K
• Complement system
  • Immunoglobulins

Classification of hematology diseases

• Hemoglobinopathies (congenital abnormality of the hemoglobin molecule or of the rate of hemoglobin synthesis)
  • Sickle-cell disease
  • Thalassemia
  • Methemoglobinemia
• Anemias (lack of red blood cells or hemoglobin)
  • Iron deficiency anemia
  • Megaloblastic anemia
    • Vitamin B₁₂ deficiency
      • Pernicious anemia
    • Folate deficiency
  • Hemolytic anemias (destruction of red blood cells)
    • Genetic disorders of RBC membrane
      • Hereditary spherocytosis
      • Hereditary elliptocytosis
    • Genetic disorders of RBC metabolism
      • Glucose-6-phosphate dehydrogenase deficiency (G6PD)
      • Pyruvate kinase deficiency
    • Immune mediated hemolytic anaemia (direct Coombs test is positive)
      • Autoimmune hemolytic anemia
        • Warm antibody autoimmune hemolytic anemia
          • Idiopathic
          • Systemic lupus erythematosus (SLE)
          • Evans' syndrome (antiplatelet antibodies and haemolytic antibodies)
        • Cold antibody autoimmune hemolytic anemia
          • Idiopathic cold hemagglutinin syndrome
          • Infectious mononucleosis
          • Paroxysmal cold hemoglobinuria (rare)
      • Alloimmune hemolytic anemia
        • Hemolytic disease of the newborn (HDN)
          • Rh disease (Rh D)
          • ABO hemolytic disease of the newborn
          • Anti-Kell hemolytic disease of the newborn
          • Rhesus c hemolytic disease of the newborn
          • Other blood group incompatibility (RhC, Rhe, RhE, Kid, Duffy, MN, P and others)
      • Drug induced immune mediated hemolytic anaemia
        • Penicillin (high dose)
        • Methyldopa
    • Hemoglobinopathies (where these is an unstable or crystaline hemoglobin)
    • Paroxysmal nocturnal hemoglobinuria (rare acquired clonal disorder of red blood cell surface protiens)
    • Microangiopathic hemolytic anemia
  • Aplastic anemia
    • Fanconi anemia
    • Diamond-Blackfan anemia
    • Acquired pure red cell aplasia
• Decreased numbers of cells
  • Myelodysplastic syndrome
  • Myelofibrosis
  • Neutropenia (decrease in the number of neutrophils)
  • Agranulocytosis
  • Glanzmann's thrombasthenia
  • Thrombocytopenia (decrease in the number of platelets)
    • Idiopathic thrombocytopenic purpura (ITP)
    • Thrombotic thrombocytopenic purpura (TTP)
    • Heparin-induced thrombocytopenia (HIT)
• Myeloproliferative disorders (Increased numbers of cells)
  • Polycythemia vera (increase in the number of cells in general)
  • Leukocytosis (increase in the number of white blood cells)
  • Thrombocytosis (increase in the number of platelets)
  • Myeloproliferative disorder
• Hematological malignancies
  • Lymphomas
    • Hodgkin's disease
    • Non-Hodgkin's lymphoma
    • Burkitt's lymphoma
    • Anaplastic large cell lymphoma
  • Myelomas
    • Multiple myeloma
    • Waldenström macroglobulinemia
  • Plasmacytoma
  • Leukemias
    • Acute lymphocytic leukemia (ALL)
    • Chronic lymphocytic leukemia (CLL)
    • Acute myelogenous leukemia (AML)
    • Chronic myelogenous leukemia (CML)
    • Hairy cell leukemia
• Coagulopathies (disorders of bleeding and coagulation)
  • Thrombocytosis
  • Recurrent thrombosis
  • Disseminated intravascular coagulation
  • Disorders of clotting proteins
    • Hemophilia
      • Hemophilia A
      • Hemophilia B (also known as Christmas disease)
      • Hemophilia C
    • Von Willebrand disease
    • Disseminated intravascular coagulation
    • Protein S deficiency
    • Antiphospholipid syndrome
  • Disorders of platelets
    • Thrombocytopenia
    • Glanzmann's thrombasthenia
    • Wiskott-Aldrich syndrome
• Miscellaneous
  • Haemochromatosis
  • Asplenia
  • Hypersplenism
    • Gauchers disease
• Haemotological changes secondary to non-haemotological disorders
  • Anemia of chronic disease
  • Infectious mononucleosis
  • AIDS
  • Malaria
  • Leishmaniasis

Tests

Tests used in the investigation of haematological problems include:

• Full blood counts
• ESR
• Blood films
• Bone marrow biopsies
• Coombs test
• serum Ferritin level
• Vitamin B12 and Folate levels
• Prothrombin time
• Partial thromboplastin time
• Protein electrophoresis
• Hemoglobin electrophoresis
• D-dimer

Treatments

Treatments include:

• Diet advice
• Oral medication - tablets or liquid medicines
• Anticoagulation therapy
• Intramuscular injections (for example, Vitamin B12 injections)
• Blood transfusion (for anemia)
• Venesection (for iron overload or polycythemia)
• Bone marrow transplant (for example, for leukemia)
• Chemotherapy (for example, for leukemia)
• Radiotherapy (in decline, for example, for leukemia)

External links

• American Society of Hematology
• BloodLine

See also

• Complete blood count
• Blood plasma
• Bone marrow examination
• Hematopathology
• Coagulation (medicine)
• Blood transfusion
• Glossary of hematology
• Dictionary of hematology

Resources

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