Anemia Flashcards
(37 cards)
What is anemia
A reduction in red blood cell count, hemoglobin content, or both.
Define Erythropoiesis
The process of production of red blood cells (erythrocytes) in the body
What hormone stimulates erythropoiesis ?
Erythropoietin ( a glycoprotein, release from the kidneys when renal O2 tension declines)
Mention two disturbances of erythropoiesis
1.Cell multiplication is inhibited because DNA synthesis is insufficient. This occurs in deficiencies of vitamin B12 or folic acid (macrocytic hyperchromic anemia). 2. Hemoglobin synthesis is impaired. This situation arises in iron deficiency, since Fe2+ is a constituent of hemoglobin (microcytic hypochromic anemia).
Deficiencies of vitamin B12 or folic acid
Macrocytic hyperchromic anemia
iron deficiency, since Fe2+ is a constituent of hemoglobin
Microcytic hypochromic anemia
General signs and symptoms of anemia
include fatigue, rapid heart- beat, shortness of breath, pale skin, dizziness, and insomnia.
Anemia can be caused by
chronic blood loss, bone marrow abnormalities, increased hemolysis, infections, malignancy, endocrine deficiencie , renal failure, and a number of other disease states.
Nutritional anemias are caused by dietary deficiencies of substances such as
iron, folic acid, and vitamin B12 (cyanocobalamin) that are necessary for nor- mal erythropoiesis.
Vitamin B12 is also known as
Cyanocobalamin
Individuals with anemia that has a genetic basis, such as sickle cell disease, can benefit from pharmacologic treatment with actions beyond nutritional supplementation, such as
hydroxyurea.
Vitamin B12 (cyanocobalamin) is produced by
bacteria; B12 generated in the colon.
Which food products are rich sources of the vitamin B12 ?
Liver, meat, fish, and milk
Hydroxycobalamin is also known as
Vitamin B12a
Deficiencies of vitamin B12 can result from
Either low dietary levels or, more commonly, poor absorption of the vitamin due to the failure of gastric parietal cells to produce intrinsic factor (as in pernicious anemia), or a loss of activity of the receptor needed for intestinal uptake of the vitamin.
Intrinsic factor is
a glycoprotein produced by the parietal cells of the stomach, and it is required for vitamin B12 absorption.
In addition to gen- eral signs and symptoms of anemia, vitamin B12 deficiency anemia may cause
tingling (pins and needles) in the hands and feet, diffi- culty walking, dementia and, in extreme cases, hallucinations, para- noia, or schizophrenia
Folate deficiency may be caused by
1) increased demand (for example, pregnancy and lacta- tion), 2) poor absorption caused by pathology of the small intestine, 3) alcoholism, or 4) treatment with drugs that are dihydrofolate reduc- tase inhibitors (for example, methotrexate, pyrimethamine, and trim- ethoprim).
A primary result of folic acid deficiency is
megaloblastic anemia (large-sized red blood cells), which is caused by diminished synthesis of purines and pyrimidines. This leads to an inability of erythropoietic tissue to make DNA and, thereby, proliferate
To avoid neurological compli-cations of vitamin B12 deficiency , it is important to
evaluate the basis of the megaloblastic anemia prior to instituting therapy. Both vitamin B12 and folate deficiency can cause similar symptom .
Folic acid is well absorbed in the
jejunum unless pathology is present. If excessive amounts of the vitamin are ingested, they are excreted in the urine and feces.
Folic Acid food products source
Leafy vegetables and liver are rich in folic acid (FA)
Causes of folic acid deficiency include:
insufficient intake, malabsorption in gastrointestinal diseases, increased requirements during preg- nancy. Antiepileptic drugs (phenytoin, primidone, phenobarbital) may de- crease FA absorption, presumably by in- hibiting the formation of monogluta- mine-FA. I
Administration of FA can mask a
vitamin B12 deficiency.