Anemia Diagnosis

  • Diagnosis

    Anemia occurs when red blood cells are reduced in number. Red blood cells are a major component of blood and serve the vital function of delivering oxygen from the lungs to the rest of the tissues in the body. When anemia occurs, the body is deprived of the oxygen it needs to function properly.

    There are many types of anemia, all of which have their own treatments. The most common types include:

    • iron-deficiency anemia
    • folic acid-deficiency anemia
    • anemia from vitamin B12 deficiency.

    Anemia may be a consequence of a chronic disease, medication, or excessive alcohol consumption. In some cases, inherited conditions that produce blood defects result in anemia.

    Most cases of anemia are corrected simply by adding more iron or folic acid to the diet. If you have a deficiency of vitamin B12, you may require intramuscular injections. Some cases are not as easily remedied.

    A person who is slightly anemic may feel tired and weak and look pale. Getting winded and having chest pains during exercise are other symptoms of anemia. In more serious cases, heartbeat irregularities or neurological symptoms such as confusion, irritability, and numbness or tingling in the extremities appear.

    Iron-deficiency anemia is the most common type of the disease, and is most often caused by excessive blood loss. When the body loses blood, it loses iron—a key part of red blood cells. Iron is needed to make hemoglobin, the protein in red blood cells that carries oxygen. Gradual, prolonged blood loss from heavy menstruation is the primary cause of iron-deficiency anemia in women. Gastrointestinal bleeding from hemorrhoids, a stomach ulcer, or an inflammatory bowel condition may also make a person anemic. Blood loss due to colon cancer and other intestinal cancers accounts for about 2% of cases. Long-term use of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen can irritate the stomach lining and cause bleeding that produces anemia. Women who are pregnant or breast-feeding sometimes become anemic when their increased iron needs are not met. Growing children, who also need more iron, occasionally become anemic. However, dietary lack is rarely the cause of iron-deficiency anemia.

    Folic acid deficiency is a type of anemia that develops when there is too little folic acid consumed in the diet, or when it is not properly absorbed in the body. The body needs folic acid to make red blood cells. Too little of this vitamin (also called folate) results in red blood cells that are abnormally large (macrocytic), and die prematurely. The body does not store folic acid in large amounts, and therefore folic acid levels need to be sustained through diet. Folic acid-deficiency anemia is caused by an inadequate intake or inability to absorb the vitamin. At certain times, such as during pregnancy and breast-feeding, the body needs more folic acid than usual. Most pregnant women are advised to take a supplement (which prevents birth defects), and the government now requires that many foods (cereals, breads, pastas) be fortified with the vitamin. People with gastrointestinal illnesses and cancers may have problems absorbing folic acid, and become anemic. Likewise, people taking certain drugs (anticonvulsants, antibiotics, birth control, pills, anticancer agents) sometimes have difficulty absorbing or metabolizing folic acid.

    Pernicious anemia is a less common but serious condition that develops when the body cannot absorb vitamin B12. Pernicious anemia is a disorder in which the immune system attacks cells in the stomach that produce intrinsic factor (IF)—a substance needed to transport vitamin B12. Without IF, a B12 deficiency develops and red blood cells grow too large and die too early. Pernicious anemia sometimes arises after intestinal surgery or from an intestinal problem than impairs metabolism of this vitamin. In older people, deterioration of the stomach lining (atrophic gastritis) and subsequent failure to produce IF is a common cause. Diet is rarely implicated in B12 deficiency, though it can be the culprit in strict vegetarians, or vegans, who do not eat any meat or dairy products, which are rich in the vitamin.

    Chronic diseases such as cancer, rheumatoid arthritis, HIV/AIDS, or alcoholism, and certain medications can also cause anemia. Chronic kidney disease is also an important cause of chronic anemia. People with cancers that affect the bone marrow, which is where the majority of red blood cells are produced, often become anemic; so do people with diseases that trigger the inflammatory process, such as rheumatoid arthritis, lupus, Grave's disease, Crohn's disease, and ulcerative colitis. Cytokines, which are proteins released during inflammation, seem to be responsible. Cytokines are essential for healing, but in excess they can interfere with iron and the hormone responsible for stimulating the production of red blood cells (erythropoietin).

    Alcoholics sometimes develop anemia because of a nutritional deficiency. Alcohol hampers vitamin absorption, and alcoholics tend to eat poorly.

    Medications can also cause anemia. Long-term use of NSAIDs may induce bleeding that results in anemia. Drugs that suppress the immune system and fight cancer can lead to aplastic anemia—anemia that occurs when the bone marrow doesn't make enough red blood cells. Additionally, certain antibiotics, blood pressure medications, and drugs used to treat heart arrythmias rarely can cause hemolytic anemia—anemia that occurs when red blood cells are destroyed prematurely.

    Rare but serious anemias such as sickle cell anemia and thalassemia are inherited. As the name implies, sickle cell anemia is characterized by sickle-shaped red blood cells. These cells are stiff, and cannot pass through the blood vessels very well. Consequently, they die after about 20 days (the average life span for a normal red blood cell is 120 days). The resulting anemia, which affects about 0.6% of the population, is serious, and can be deadly. Thalassemia is an inherited blood disorder that stems from a defect in the rate at which hemoglobin is produced. The two main types are thalassemia major (Cooley's anemia) and thalassemia minor (the more common of the two). Thalassemia can be very serious, but the condition is rare; it is more commonly found in people of Mediterranean descent.

    Anemia produces a variety of symptoms, including weakness, fatigue, and paleness (pallor). Depending on the cause, other symptoms may be present as well. The oxygen deprivation from anemia can make you feel tired and weak, dizzy, short of breath, and confused. Your skin may turn pale—particularly in places that are normally red such as your gums, nail beds, and inner eyelids.

    Some people with an iron deficiency develop cravings for nonfood items, such as clay and detergent, a rare condition known as pica. Severe iron deficiency also may cause tongue irritation, cracks in the corners of the mouth, and a spoonlike deformity in the fingernails.

    People with pernicious anemia often develop neurologic symptoms. A lack of B12 can initially produce tingling sensations in the hands and feet. This can progress to serious loss of neurologic function.

    Although anemia can strike anyone at any age, it is more common in women and in older people. Iron loss from menstruation and vitamin deficiencies that develop during pregnancy and breastfeeding are the main reasons why younger women are five times more likely than younger men to develop anemia. However, aging increases anemia risk for everyone. One out of every 100 people over the age of 60 has been diagnosed with pernicious anemia. Gastrointestinal bleeding is a major contributor to anemia in older age groups.

    Alcoholics, serious athletes, and people with chronic illnesses are at increased risk for anemia. Alcoholics often eat poorly, and the resulting malnutrition leads to anemia. Alcohol also hinders the absorption of nutrients important for preventing anemia. Additionally, internal bleeding, which is more likely in alcoholics, increases risk as well.

    Intense physical training, such as that required for a marathon, sometimes results in gastrointestinal bleeding and damage to red blood cells, resulting in a condition called “sports anemia.”

    Anyone who has a chronic illness that produces inflammation or bleeding is at increased risk for anemia.

    The kidneys are involved in producing a protein that helps in red cell production. People with chronic kidney disease often have anemia because their kidneys do not make enough of this protein.

    To determine what is causing your symptoms, your doctor will start with a medical history and do a physical examination. Your doctor will ask you about your nutritional habits. If you are female, he or she will ask you about your periods and, regardless of your sex, about whether you have seen blood in your stool. He or she will also look for signs of pallor and check to see if your lymph nodes are swollen and if your spleen is enlarged.

    A complete blood cell count can confirm anemia If your doctor suspects anemia, he or she will order a complete blood cell count. For this test, many different types of blood cells are counted and examined. The most relevant for diagnosing anemia are the red blood cell count, hemocrit, and hemoglobin Table 01.

    The red blood cell count determines how many red blood cells you have, and a blood smear can show what shape they are (an important feature in determining which type of anemia you have). Red blood cells that are pale and small or uneven suggest an iron deficiency, and those that are too big and misshapen hint at a B12 or folic acid deficiency.

    The hemocrit value reveals the percentage of red blood cells in your total blood volume. Hemoglobin is the pigment that gives red blood cells their color, and the key chemical needed to transport oxygen.

    If your red blood cell count or hemoglobin is low, your doctor will order more blood work to determine the nature of your anemia. Blood test can determine if you have sickle cell disease or thallassemia. Your doctor will check the levels of an iron-binding protein called ferritin in your blood. If levels are low, it is likely that an iron deficiency is causing your anemia. The doctor will also check your B12 and folic acid levels. If a B12 deficiency is established, your doctor will check to see if pernicious anemia is the culprit by looking for antibodies for intrinsic factor. To diagnose the less common forms of anemia, a bone marrow aspiration and biopsy, and other specialized tests are necessary.

    Once your type of anemia is established, the next step is to find out what is causing it. Your doctor will probably want to check your stool for evidence of blood. He or she may order specific tests that can reveal gastrointestinal bleeding and cancer.

    Table 1.  Normal Hemoglobin and Hemocrit Values

    Age Hemoglobin Hemocrit
    Newborn 145-225 g/L 45%-67%
    Under 2 105-135 g/L 33%-39%
    12-18 (male) 130-160 g/L 37%-49%
    12-18 (female) 120-160 g/L 36%-46%
    Over 18 (male) 135-175 g/L 41%-53%
    Over 18 (female) 120-160 g/L 36%-46%

    A healthy diet—and, in some cases, supplements—may prevent anemias associated with vitamin deficiencies.

    • Folic acid. Women of childbearing age in particular should be careful to get enough folic acid to prevent birth defects in a developing fetus. The government recommends 400 mcg daily. Leafy green vegetables, beans, and whole grains are excellent food sources. Many breakfast cereals are fortified with folic acid. A daily supplement can be taken for insurance.
    • Iron. Red meat provides ample iron. Beans, dried fruits, and nuts are good vegetarian sources. In fact, it is difficult to get too little dietary iron; most people get too much. The average person needs just 10 mg daily; younger women need 15 mg, and pregnant women should get 30 mg. However, if you are a woman and your periods are very heavy, you may want to discuss iron supplementation with your doctor.
    • Vitamin B12. Meat, fish, eggs, and cheese are rich in vitamin B12. Most people have no problem getting the recommended daily 2.4 mcg of this vitamin. Strict vegetarians who avoid animal products, known as vegans, however, may fall short in B12 requirements, and should ask a doctor about supplementation.

    Don't overcook food, as this may destroy some nutrients.

    Drink alcohol and caffeinated beverages such as soda, coffee, and tea sparingly, as these may interfere with the absorption of nutrients important for preventing anemia.

    If you take aspirin or NSAIDs regularly, take them in moderation. Excess NSAID use can lead to stomach bleeding that you may not even notice, and thus anemia.

    Women with heavy periods should talk to their doctor about this for certain medications that may decrease the bleeding and the likelihood of anemia.
  • Prevention and Screening

    A healthy diet—and, in some cases, supplements—may prevent anemias associated with vitamin deficiencies.

    • Folic acid. Women of childbearing age in particular should be careful to get enough folic acid to prevent birth defects in a developing fetus. The government recommends 400 mcg daily. Leafy green vegetables, beans, and whole grains are excellent food sources. Many breakfast cereals are fortified with folic acid. A daily supplement can be taken for insurance.
    • Iron. Red meat provides ample iron. Beans, dried fruits, and nuts are good vegetarian sources. In fact, it is difficult to get too little dietary iron; most people get too much. The average person needs just 10 mg daily; younger women need 15 mg, and pregnant women should get 30 mg. However, if you are a woman and your periods are very heavy, you may want to discuss iron supplementation with your doctor.
    • Vitamin B12. Meat, fish, eggs, and cheese are rich in vitamin B12. Most people have no problem getting the recommended daily 2.4 mcg of this vitamin. Strict vegetarians who avoid animal products, known as vegans, however, may fall short in B12 requirements, and should ask a doctor about supplementation.

    Don't overcook food, as this may destroy some nutrients.

    Drink alcohol and caffeinated beverages such as soda, coffee, and tea sparingly, as these may interfere with the absorption of nutrients important for preventing anemia.

    If you take aspirin or NSAIDs regularly, take them in moderation. Excess NSAID use can lead to stomach bleeding that you may not even notice, and thus anemia.

    Women with heavy periods should talk to their doctor about this for certain medications that may decrease the bleeding and the likelihood of anemia.

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