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Vitamin B12 deficiency or pernicious anemia
- Pernicious anemia is a type of megaloblastic anemia
- Due to poor vitamin B12 absorption from the GI tract
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Vitamin B12 deficiency Caused by intrinsic factor deficiency, a protein produced by the stomach that binds to vitamin B12
- 1} When the stomach does not make enough intrinsic factor, the small intestine cannot properly absorb vitamin B12 and the intrinsic factor
- {2} Without vitamin B12 and intrinsic factor, immature rbcs membranes rupture easily, thus fewer rbcs and reduced O2-carrying capacity
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Causes of pernicious anemia
- Weakened stomach lining (atrophic gastric mucosa)
- {2} Autoimmunity against gastric parietal cells that make intrinsic factor
- {3} Autoimmunity against intrinsic factor itself
- {4} Bacterial infection causing pathological conditions that either
- {a} Impair vitamin B12 absorption
- {b} Enhance vitamin B12 elimination
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Sources of vitamin B12
{1} Animal products{2} Vitamin B12 supplements
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Symptoms of pernicious anemia
- {1} Abdominal distress
- {2} Burning of the tongue
- {3} Central nervous system effects
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Folic acid deficiency anemia
Due to insufficient folic acid (folate, vitamin B9) levels essential for body growth and to synthesize DNA
Low serum folic acid levels conclusive for this disease
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Folic acid deficiency anemia - Absorbed in small intestines and absorption is affected by (5)
- {1} Chronic alcoholism
- {2} Poor nutrition
- {3} Pregnant and lactating females
- {4} Kidney disease
- {5} Inflammatory bowel disease
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Hemolytic anemia
Insufficient rbcs in blood due to premature destruction
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Hemolytic anemia Causes include
- {1} Inherited abnormalities
- {a} Hemoglobin defects
- {b} Enzyme defects
- {c} rbc membrane defects
- {2} Infections microorganisms
- {3} Medications
- {4} Immune disorders
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Hemolytic anemia - Significant rbc destruction leads to
jaundice
- {1} Caused by excess yellow-orange bile pigments or bilirubin, a chemical produced when the liver breaks down rbcs
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Yellow-orange color is evident in
{ a} Sclera {b} Skin {c} Urine {d} Feces
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Hemolytic anemia - Treatments
- {1} Splenectomy
- {2} Blood transfusions
- {3} Antibiotics for infections causing hemolytic anemia
- {4} Immunosuppressive therapy for immune disorders causing hemolytic anemia
- {5} Discontinue medications causing hemolytic anemia
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Hemoglobinopathies
Diseases where genetic defects produce abnormal hemoglobins and/or anemia
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Types of Hemoglobinopathies
- Sickle cell anemia
- Thalassemia
- Polycythemia vera
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Sickle cell anemia
- {1}Autosomal recessive inherited disease
- {a} Homozygous- full blown disease
- {b} Heterozygous- Sickle cell trait
- {2} Found in ~10% of African-Americans
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Sickle cell anemia is cause by
- {3} Caused by an abnormal type of hemoglobin called hemoglobin S that distorts the shape of rbcs under low O2 conditions
- {a} Hemoglobin S molecules form long crystals by cross-linking with each other
- {b} As O2 is released from rbcs, the rbcs become sickle-shaped
- {c} Sickle-shaped rbcs are inflexible and rigid causing mechanical obstruction of small arterioles and capillaries
- {d} Pain and ischemia occurs ultimatelyn leading to organ failure
- {e} Sickle-shaped rbcs more fragile than normal rbcs leading to rbc hemolysis (hemolytic anemia)
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Sickle cell anemia Treatments
- {a} Narcotic analgesics to manage pain from sickle cell crisis
- {b} Blood transfusions and fluid replacement to expand blood volume
- {c} O2 for reperfusion or occluded arteries
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