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Harrison's Principles of Internal Medicine, 18e
| Part 7. Oncology and Hematology > Section 2. Hematopoietic Disorders > |
General Pathophysiology
Sections: Compensated Hemolysis versus Ha, Inherited Hemolytic Anemias, Hemolytic Anemias Due to Abnormalities of the Membrane-Cytoskeleton Complex, Hereditary Spherocytosis (HS), Clinical Presentation and Diagnosis, Treatment: Hereditary Spherocytosis, Hereditary Elliptocytosis (HE), Disorders of Cation Transport, Enzyme Abnormalities, Abnormalities of the Glycolytic Pathway, Pyruvate Kinase Deficiency, Treatment: Pryuvate Kinase Deficiency, Other Glycolytic Enzyme Abnormalities, Abnormalities of Redox Metabolism, G6PD Deficiency, Genetic Considerations, Epidemiology, Clinical Manifestations, Laboratory Diagnosis, Treatment: G6PD Deficiency, Other Abnormalities of the Redox System, Pyrimidine 5'-Nucleotidase (P5N) Deficiency, Familial (Atypical) Hemolytic Uremic Syndrome (aHUS), Acquired Hemolytic Anemia, Mechanical Destruction of Red Cells, Toxic Agents and Drugs, Infection, Autoimmune Hemolytic Anemia (AIHA), Pathophysiology, Clinical Features, Treatment: Autoimmune Hemolytic Anemia, Paroxysmal Cold Hemoglobinuria (PCH), Cold Agglutinin Disease (CAD), Paroxysmal Nocturnal Hemoglobinuria (PNH), Clinical Features, Laboratory Investigations and Diagnosis, Pathophysiology, Bone Marrow Failure (BMF) and Relationship between PNH and Aplastic Anemia (AA), Treatment: Paroxysmal Nocturnal Hemoglobinuria.
Topics Discussed: abnormal cation transport syndrome; anemia, hemolytic, acquired; anemia, hemolytic, congenital; anemias; autoimmune hemolytic anemia; cold hemagglutinin disease; deficiency of pyruvate kinase; glucose-6-phosphate dehydrogenase deficiency; hematologic disorders, drug-induced; hemoglobinuria; hemolysis; hemolytic anemia; hemolytic-uremic syndrome; hereditary elliptocytosis; hereditary spherocytosis; paroxysmal cold hemoglobinuria; paroxysmal nocturnal hemoglobinuria; pathophysiology of blood disorders; red and white blood cells; red blood cell metabolism; uridine monophosphate hydrolase deficiency.
Excerpt:"The mature red cell is the product of a developmental pathway that brings the phenomenon of differentiation to an extreme. An orderly sequence of events produces synchronous changes whereby the gradual accumulation of a huge amount of hemoglobin in the cytoplasm (to a final level of 340 g/L, i.e. about 5 mM) goes hand in hand with the gradual loss of cellular organelles and of biosynthetic abilities. In the end, the erythroid cell undergoes a process that has features of apoptosis, including nuclear pyknosis and actual loss of the nucleus. However, the final result is more altruistic than suicidal; the cytoplasmic body, instead of disintegrating, is now able to provide oxygen to all cells in the human organism for some remaining 120 days of the red cell "life" span.Red cell destruction is a potent stimulus for erythropoiesis, which is mediated by erythropoietin (EPO) produced by the kidney. This mechanism is so effective that in many cases the increased output of red cells from the bone marrow can fully balance an increased destruction of red cells. In such cases we say that hemolysis is compensated. The pathophysiology of compensated hemolysis is similar to what we have just described, except there is no anemia. This notion is important from the..."
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