Human Diseases and Conditions

What Is Anemia?

Maybe your day is so packed with things to do that you hardly have time to grab breakfast, let alone make sure you're eating right the rest of the day. Perhaps you're staying up late to get your homework finished and missing out on the sleep you need. The fact is, lots of teens are tired. And with all the demands of school and other activities, it's easy to understand why.
For some people, though, there may be another explanation for why they feel so exhausted: anemia.
To understand anemia, it helps to start with breathing. The oxygen we inhale doesn't just stop in our lungs. It's needed throughout our bodies to fuel the brain and all our other organs and tissues that allow us to function. Oxygen travels to these organs through the bloodstream — specifically in the red blood cells.
Red blood cells, or RBCs, are manufactured in the body's bone marrow and act like boats, ferrying oxygen throughout the rivers of the bloodstream. RBCs contain hemoglobin (pronounced: hee-muh-glow-bin), a protein that holds onto oxygen. To make enough hemoglobin, the body needs to have plenty of iron. We get this iron, along with the other nutrients necessary to make red blood cells, from food.
Anemia occurs when a person has fewer RBCs than normal. This can happen for three main reasons:

1. Red blood cells are being lost.
2. The body is producing RBCs slower than it should.
3. RBCs are being destroyed by the body.

Each of these causes is linked to a different type of anemia.
Signs and symptoms vary depending on the cause of your anemia, but may include:

• Fatigue
• Pale skin
• A fast or irregular heartbeat
• Shortness of breath
• Chest pain
• Dizziness
• Cognitive problems
• Cold hands and feet
• Headache

Initially, anemia can be so mild it goes unnoticed. But signs and symptoms increase as anemia worsens.

 Causes
Blood consists of a liquid called plasma and cells. Floating within the plasma are three types of blood cells:

• White blood cells (leukocytes). These blood cells fight infection.
• Platelets. These blood cells help your blood clot after a cut.
• Red blood cells (erythrocytes). These blood cells carry oxygen from your lungs, via your bloodstream, to your brain and the other organs and tissues. Your body needs a supply of oxygenated blood to function. Oxygenated blood helps give your body its energy and your skin a healthy glow.

Red blood cells contain hemoglobin — a red, iron-rich protein that gives blood its red color. Hemoglobin enables red blood cells to carry oxygen from your lungs to all parts of your body, and to carry carbon dioxide from other parts of the body to your lungs so that it can be exhaled.
Most blood cells, including red blood cells, are produced regularly in your bone marrow — a red, spongy material found within the cavities of many of your large bones. To produce hemoglobin and red blood cells, your body needs iron, other minerals, protein and vitamins from the foods you eat.
Causes of common types of anemia
When you're anemic, your body produces too few healthy red blood cells, loses too many of them or destroys them faster than they can be replaced. Common types of anemia and their causes include:

• Iron deficiency anemia. This common form of anemia affects about 1 to 2 percent of adults in the United States. The cause is a shortage of the element iron in your body. Your bone marrow needs iron to make hemoglobin. Without adequate iron, your body can't produce enough hemoglobin for red blood cells. The result is iron deficiency anemia.
• Vitamin deficiency anemias. In addition to iron, your body needs folate and vitamin B-12 to produce sufficient numbers of healthy red blood cells. A diet lacking in these and other key nutrients can cause decreased red blood cell production. Additionally, some people are unable to effectively absorb B-12.
• Anemia of chronic disease. Certain chronic diseases — such as cancer, HIV/AIDS, rheumatoid arthritis, Crohn's disease and other chronic inflammatory diseases — can interfere with the production of red blood cells, resulting in chronic anemia. Kidney failure also can be a cause of anemia.
• Aplastic anemia. This very rare, life-threatening anemia is caused by a decrease in the bone marrow's ability to produce all three types of blood cells — red blood cells, white blood cells and platelets. Many times, the cause of aplastic anemia is unknown, but it's believed to often be an autoimmune disease.
• Anemias associated with bone marrow disease. A variety of diseases, such as leukemia and myelodysplasia, a preleukemic condition, can cause anemia by affecting blood production in your bone marrow. The effects of these types of cancer and cancer-like disorders vary from a mild alteration in blood production to a complete, life-threatening shutdown of the blood-making process. Other cancers of the blood or bone marrow, such as multiple myeloma, myeloproliferative disorders and lymphoma, can also cause anemia.
• Hemolytic anemias. This group of anemias develops when red blood cells are destroyed faster than bone marrow can replace them. Certain blood diseases can cause increased red blood cell destruction. Autoimmune disorders can cause your body to produce antibodies to red blood cells, destroying them prematurely. Certain medications, such as some antibiotics used to treat infections, also can break down red blood cells.
• Sickle cell anemia. This inherited and sometimes serious anemia, which more commonly affects people of African, Arabic and Mediterranean descent, is caused by a defective form of hemoglobin that forces red blood cells to assume an abnormal crescent (sickle) shape. These irregular-shaped red blood cells die prematurely, resulting in a chronic shortage of red blood cells.
• Other anemias. There are several other, rarer forms of anemia, such as thalassemia and anemias caused by defective hemoglobin.

Sometimes, no cause of anemia can be identified.

How is anemia diagnosed?

Anemia is usually detected or at least confirmed by a complete blood cell (CBC) count. CBC test may be ordered by a physician as a part of routine general check-up and screening or based on clinical signs and symptoms that may suggest anemia or other blood abnormalities.

How is anemia treated?

The treatment of the anemia varies greatly. First, the underlying cause of the anemia should be identified and corrected. For example, anemia as a result of blood loss from a stomach ulcer should begin with medications to heal the ulcer. Likewise, surgery is often necessary to remove a colon cancer that is causing chronic blood loss and anemia.
Sometimes iron supplements will also be needed to correct iron deficiency. In severe anemia, blood transfusions may be necessary. Vitamin B12 injections will be necessary for patients suffering from pernicious anemia or other causes of B12 deficiency.
In certain patients with bone marrow disease (or bone marrow damage from chemotherapy) or patients with kidney failure, epoetin alfa (Procrit, Epogen) may be used to stimulate bone marrow red blood cell production.
If a medication is thought to be the culprit, then it should be discontinued under the direction of the prescribing doctor.

What are the complications of anemia?

As mentioned earlier, hemoglobin has the important role of delivering oxygen to all parts of the body for consumption and carries back carbon dioxide back to the lung to exhale it out of the body. If hemoglobin level is too low, this process may be impaired, resulting in body having low oxygen level (hypoxia).

Refrence

1. Anemia. National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/health/dci/Diseases/anemia/anemia_whatis.html. Accessed Dec. 8, 2008.
2. Pernicious anemia. National Heart, Lung, and Blood Institute. http://www.nhlbi.nih.gov/health/dci/Diseases/prnanmia/prnanmia_all.html. Accessed Dec. 10, 2008.
3. Schrier SL. Patient information: Iron deficiency anemia. http://www.uptodate.com/home/index.html. Accessed Nov. 25, 2008.
4. Schrier SL, et al. Anemia of chronic disease (anemia of chronic inflammation). http://www.uptodate.com/home/index.html. Accessed Nov. 25, 2008.
5. Schrier SL. Aplastic anemia: Pathogenesis; clinical manifestations; and diagnosis. http://www.uptodate.com/home/index.html. Accessed Nov. 25, 2008.