Alterations of Erythrocyte
Function
Chapter 26
1
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
2
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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
3
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Anemia

Anisocytosis


Red cells are present in various sizes
Poikilocytosis

Red cells are present in various shapes
4
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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
5
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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
6
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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
7
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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
8
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Pernicious Anemia
9
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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
10
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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
11
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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
12
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Iron Deficiency Anemia
13
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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
14
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Microcytic-Hypochromic Anemias

Sideroblastic anemia



Dimorphism
Myelodysplastic syndrome
Erythropoietic hemochromatosis
15
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Normocytic-Normochromic
Anemias

Characterized by red cells that are relatively
normal in size and hemoglobin content but
insufficient in number
16
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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
17
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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
18
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Drug-Induced Hemolytic Anemia
19
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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
20
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Anemia of Chronic Inflammation
21
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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
22
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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
23
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