ANEMIA
What Is Anemia? Anemia is a deficiency of red blood cells.
Red blood cells are the oxygen-transporting cells of the blood; they are
produced and released into the circulation by the bone marrow, obtain oxygen in the lungs, and are pumped
throughout the body by the heart. Anemia occurs due to insufficient production of red blood cells, excessive destruction of
red blood cells, or blood loss.
What Causes Anemia? To produce red blood cells, the body requires iron, folic acid (folate), and vitamin B12, among other nutrients. When these building blocks are in short supply, bone marrow production of red blood cells declines. Conditions in which excessive destruction occur include thalassemia, sickle cell anemia, and certain autoimmune diseases, when the immune system reacts against the body’s own tissues. Red cell destruction can also occur as a side effect of some drugs and toxins, and in people with prosthetic heart valves. Anemia due to blood loss is most common in women of
child-bearing age due to menstruation. Less obvious blood loss can occur in the gastro-intestinal tract in illnesses such as peptic ulcer disease and various cancers (e.g. of the stomach and colon).
What Are The Signs And Symptoms Of Anemia? When there are insufficient red blood cells, oxygen delivery is compromised. Therefore, anemia can cause weakness, fatigue, and a general sense of malaise. Headaches, dizziness, and pale skin are also common. As the heart tries to pump more blood to maintain oxygen transport, the heart beats may increase or become irregular; this might be manifested as shortness of breath or palpitations (the sensation of the heart pounding or "skipping a beat"). If oxygen supply to the brain is sufficiently reduced, fainting may occur. These signs and symptoms of anemia are not specific; that is, they are general complaints common to a number of medical conditions.
How Is Anemia Diagnosed? Anemia is initially investigated by a simple blood test involving measuring the amount of hemoglobin in the blood. Hemoglobin is an iron-containing protein that carries oxygen in the red blood cells: low hemoglobin is indicative of
reduced red blood cells. Further tests should be conducted to determine the cause of anemia; this will determine an appropriate course of action.
Iron Deficiency Anemia: This is the commonest form of anemia in developed countries, and occurs primarily in women of reproductive age, adolescent girls, and young children. As many as 1 in 10 women and children in North America are iron-deficient and thus at risk for iron-deficiency anemia. Iron deficiency occurs due to blood loss (menstruation, gastro-intestinal ulcers or polyps), insufficient dietary intake (strict vegetarians), conditions of malabsorption (celiac sprue, Crohn’s disease), and increased iron demand (e.g. pregnancy, breast feeding, and periods of rapid growth). Teenage girls require 10 mg of iron per day, and adult women require 15 mg. Dietary sources of iron include red meat, fish, poultry and dark green vegetables like broccoli and spinach. Iron is best absorbed from plant sources when accompanied by a source of vitamin C, such as citrus fruit. Conversely, tea, coffee, and cigarette smoking reduce iron absorption. Iron supplements should not
be taken unless they are recommended by your doctor after diagnosis of iron deficiency.
Pernicious Anemia:
Vitamin B-12 is another nutrient required for red blood cell production; it is obtained from animal products and legumes in the diet. Pernicious anemia is a hereditary condition of defective vitamin B-12 absorption resulting from failed production of a protein
called intrinsic factor by cells lining the stomach. Intrinsic factor binds to vitamin B-12 in the stomach for absorption in the intestine. A person with pernicious anemia may experience decreased appetite, diarrhea, and vague abdominal pain. Anemia usually develops insidiously; it is treated with lifelong injections of vitamin B-12. Anemia caused by vitamin B-12 deficiency in the diet can also occur, especially in strict vegans; this is not pernicious anemia, and can be resolved by increased dietary intake or oral supplements of B-12.
Folate Deficiency Anemia: Dietary sources of
folate include vegetables, mushrooms, and liver. Alcohol can interfere with its absorption; thus, those most susceptible to folate deficiency are chronic alcoholics and people with poor
diets. Oral contraceptives, anticonvulsants, and malabsorption syndromes like celiac sprue can also result in folate deficiciency, as can conditions of increased demand such as pregnancy and long-term dialysis. Folate stores can be replenished with oral supplementation, 1 mg per day.
Many other causes of anemia exist and are generally diagnosed with the use of appropriate lab tests.
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