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| '''Anemia''' is the most common disorder of the ]. Anemia occurs when the |
'''Anemia''' is the most common disorder of the ]. Anemia occurs when the number of ] (RBC) or the amount of ] (an oxygen-carrying ] in the blood) in the blood becomes low. The blood of an anemic person has trouble carrying oxygen to tissues which become, in a sense, "starved" of oxygen. Deprived of oxygen, the tissues cannot produce enough energy to function properly. | ||
| There are several kinds of anemia produced by a variety of underlying causes |
There are several kinds of anemia, produced by a variety of underlying causes. The initial classification of anemia is made on the basis of the appearance of the red blood cells on microscopic examination of a peripheral blood smear. If the cells are smaller than normal, the anemia is said to be ''microcytic''; if they are normal size, ''normocytic''; and if they are larger than normal, the anemia is classified as ''macrocytic''. Other characteristics visible on the peripheral smear may provide valuable clues about a more specific diagnosis. | ||
| The most common causes of macrocytic anemia are a deficiency of ], due either to inadequate intake or insufficient absorption, or a deficiency of ]. | |||
| Normocytic anemia can be caused by acute blood loss or chronic disease. | |||
| The most common and most severe type of microcytic anemia, and the most common cause of anemia overall, is iron-deficiency anemia. Just as the name implies, this form of anemia caused when the dietary intake or absorption of iron is insufficient. In the United States, 20% of all women of childbearing age have iron-deficiency anemia, compared with only 2% of adult men. The principal cause of iron-deficiency anemia in premenopausal women is blood lost during menses. | |||
| When the body has sufficient iron to meet its needs (functional iron), the remainder is stored for later use in the bone marrow, liver, and spleen. Iron-deficiency ranges from iron depletion, which yields no physiological damage, to iron-deficiency anemia, which can affect the function of numerous organ systems. Iron-depletion causes the amount of stored iron to be reduced, but has no affect on the functional iron. However, a person with no stored iron has no reserves to use if the body requires more iron. In essence, the amount of iron absorbed by the body is not adequate for growth and development or to replace the amount lost. Iron-deficiency anemia is the final stage of iron deficiency. | When the body has sufficient iron to meet its needs (functional iron), the remainder is stored for later use in the bone marrow, liver, and spleen. Iron-deficiency ranges from iron depletion, which yields no physiological damage, to iron-deficiency anemia, which can affect the function of numerous organ systems. Iron-depletion causes the amount of stored iron to be reduced, but has no affect on the functional iron. However, a person with no stored iron has no reserves to use if the body requires more iron. In essence, the amount of iron absorbed by the body is not adequate for growth and development or to replace the amount lost. Iron-deficiency anemia is the final stage of iron deficiency. | ||
Revision as of 02:52, 11 September 2002
Anemia is the most common disorder of the blood. Anemia occurs when the number of red blood cells (RBC) or the amount of hemoglobin (an oxygen-carrying protein in the blood) in the blood becomes low. The blood of an anemic person has trouble carrying oxygen to tissues which become, in a sense, "starved" of oxygen. Deprived of oxygen, the tissues cannot produce enough energy to function properly.
There are several kinds of anemia, produced by a variety of underlying causes. The initial classification of anemia is made on the basis of the appearance of the red blood cells on microscopic examination of a peripheral blood smear. If the cells are smaller than normal, the anemia is said to be microcytic; if they are normal size, normocytic; and if they are larger than normal, the anemia is classified as macrocytic. Other characteristics visible on the peripheral smear may provide valuable clues about a more specific diagnosis.
The most common causes of macrocytic anemia are a deficiency of Vitamin B12, due either to inadequate intake or insufficient absorption, or a deficiency of folic acid.
Normocytic anemia can be caused by acute blood loss or chronic disease.
The most common and most severe type of microcytic anemia, and the most common cause of anemia overall, is iron-deficiency anemia. Just as the name implies, this form of anemia caused when the dietary intake or absorption of iron is insufficient. In the United States, 20% of all women of childbearing age have iron-deficiency anemia, compared with only 2% of adult men. The principal cause of iron-deficiency anemia in premenopausal women is blood lost during menses.
When the body has sufficient iron to meet its needs (functional iron), the remainder is stored for later use in the bone marrow, liver, and spleen. Iron-deficiency ranges from iron depletion, which yields no physiological damage, to iron-deficiency anemia, which can affect the function of numerous organ systems. Iron-depletion causes the amount of stored iron to be reduced, but has no affect on the functional iron. However, a person with no stored iron has no reserves to use if the body requires more iron. In essence, the amount of iron absorbed by the body is not adequate for growth and development or to replace the amount lost. Iron-deficiency anemia is the final stage of iron deficiency.