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Alterations of Erythrocyte
Function
Chapter 26
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Anemia
Reduction in the total number of erythrocytes
in the circulating blood or in the quality or
quantity of hemoglobin
Impaired erythrocyte production
Acute or chronic blood loss
Increased erythrocyte destruction
Combination of the above
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Anemia
Classifications
Etiology
Morphology
Based on MCV, MCH, and MCHC values
Size
Identified by terms that end in -cytic
Macrocytic, microcytic, normocytic
Hemoglobin content
Identified by terms that end in -chromic
Normochromic and hypochromic
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Anemia
Anisocytosis
Red cells are present in various sizes
Poikilocytosis
Red cells are present in various shapes
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Anemia
Physiologic manifestation
Reduced oxygen carrying capacity
Variable symptoms based on severity and the
ability for the body to compensate
Classic anemia symptoms
Fatigue, weakness, dyspnea, and pallor
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Macrocytic-Normochromic
Anemias
Also termed megaloblastic anemias
Characterized by defective DNA synthesis
Due to deficiencies in vitamin B12 or folate
Coenzymes for nuclear maturation and the DNA
synthesis pathway
Ribonucleic acid (RNA) processes occur at a
normal rate
Results in the unequal growth of the nucleus and
cytoplasm
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Macrocytic-Normochromic
Anemias
Pernicious anemia
Caused by a lack of intrinsic factor from the
gastric parietal cells
Required for vitamin B12 absorption
Results in vitamin B12 deficiency
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Macrocytic-Normochromic
Anemias
Pernicious anemia
Typical anemia symptoms
Neurologic manifestations
Others
Nerve demyelination
Loss of appetite, abdominal pain, beefy red tongue
(atrophic glossitis), icterus, and splenic enlargement
Treatment
Parenteral or high oral doses of vitamin B12
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Pernicious Anemia
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Macrocytic-Normochromic
Anemias
Folate deficiency anemia
Absorption of folate occurs in the upper small
intestine
Not dependent on any other facilitating factor
Similar symptoms to pernicious anemia except
neurologic manifestations are generally not seen
Treatment requires daily oral administration of
folate
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Microcytic-Hypochromic Anemias
Characterized by red cells that are abnormally
small and contain reduced amounts of
hemoglobin.
Related to:
Disorders of iron metabolism
Disorders of porphyrin and heme synthesis
Disorders of globin synthesis
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Microcytic-Hypochromic Anemias
Iron deficiency anemia
Most common type of anemia worldwide
Nutritional iron deficiency
Metabolic or functional deficiency
Progression of iron deficiency causes:
Brittle, thin, coarsely ridged, and spoon-shaped nails
A red, sore, and painful tongue
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Iron Deficiency Anemia
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Microcytic-Hypochromic Anemias
Sideroblastic anemia
Group of disorders characterized by anemia
Altered mitochondrial metabolism causing
ineffective iron uptake and resulting in
dysfunctional hemoglobin synthesis
Ringed sideroblasts within the bone marrow are
diagnostic
Sideroblasts are erythroblasts that contain iron
granules that have not been synthesized into
hemoglobin
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Microcytic-Hypochromic Anemias
Sideroblastic anemia
Dimorphism
Myelodysplastic syndrome
Erythropoietic hemochromatosis
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Normocytic-Normochromic
Anemias
Characterized by red cells that are relatively
normal in size and hemoglobin content but
insufficient in number
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Normocytic-Normochromic
Anemias
Aplastic anemia
Pancytopenia
Pure red cell aplasia
Fanconi anemia
Posthemorrhagic anemia
Acute blood loss from the vascular space
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Normocytic-Normochromic
Anemias
Hemolytic anemia
Accelerated destruction of red blood cells
Autoimmune hemolytic anemias
Immunohemolytic anemia
Warm antibody immunohemolytic anemia
Drug-induced hemolytic anemia
Cold agglutinin immunohemolytic anemia
Cold hemolysin hemolytic anemia
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Drug-Induced Hemolytic Anemia
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Normocytic-Normochromic
Anemias
Sickle cell anemia
Anemia of chronic inflammation
Mild to moderate anemia seen in:
AIDS, rheumatoid arthritis, lupus erythematosus,
hepatitis, renal failure, and malignancies
Pathologic mechanisms
Decreased erythrocyte life span
Ineffective bone marrow response to erythropoietin
Altered iron metabolism
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Anemia of Chronic Inflammation
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Myeloproliferative RBC Disorders
Polycythemia
Overproduction of red blood cells
Relative polycythemia
Result of dehydration
Fluid loss results in relative increases of red cell
counts and Hgb and Hct values
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Polycythemia
Absolute polycythemia
Primary absolute
Abnormality of stem cells in the bone marrow
Polycythemia vera (PV)
Secondary absolute
Increase in erythropoietin as a normal response to
chronic hypoxia or an inappropriate response to
erythropoietin-secreting tumors
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