Anemia

C

Bleeding

Excessive bleeding can cause dangerously low blood pressure as well as insufficient oxygen delivery to body tissues. Large amounts of blood loss may occur suddenly due to injury or surgery. In some cases, excessive bleeding may occur over time, such as from bleeding ulcers or tumors of the intestinal tract.

III

Types of Anemia

There are more than 100 types of anemia. The most common type is iron-deficiency anemia. When the body’s need for iron increases—such as during periods of rapid growth in childhood, during pregnancy, or when there is chronic bleeding—an iron deficiency may develop. Low iron levels impair the body’s ability to produce hemoglobin, a primary component of red blood cells.

Pernicious anemia, a chronic ailment that mostly affects people over 40, is a result of vitamin B₁₂ deficiency. This vitamin is normally found in meats and vegetables and is essential for the maturation of red blood cells. People with pernicious anemia are unable to produce intrinsic factor, a substance that allows the small intestine to absorb vitamin B₁₂. This inability may be caused by a genetic disorder, Crohn’s disease (an immune system disorder that causes chronic inflammation of the digestive tract), or surgery that removes the part of the stomach that normally produces intrinsic factor.

Aplastic anemia occurs when bone marrow, the tissue that produces new red blood cells, becomes diseased or injured. Bone marrow damage may result from a viral infection, cancer, radiation, or exposure to toxic chemicals, including arsenic, benzene, and some antibiotics and cancer medications.

---

---

Sickle-cell anemia is an inherited disorder that affects mostly people of African ancestry. People with sickle-cell anemia have an abnormal form of hemoglobin that distorts red blood cells. These distorted cells are called sickled cells because of their resemblance to the sickle, a type of crescent-shaped cutting blade used in agriculture. The sickled shape makes it difficult for these cells to pass through tiny blood vessels, preventing oxygen in the blood from reaching organs and tissues.

IV

Treatment

Physicians treat anemia associated with a serious disease by treating the underlying disorder. In some cases, when symptoms persist or worsen, additional medications that boost red blood cells may be necessary to avoid life-threatening conditions and improve quality of life. For instance, doctors prescribe iron pills to treat iron-deficiency anemia and injections of vitamin B₁₂ to treat pernicious anemia. Synthetically manufactured erythropoietin stimulates the production and growth of red blood cells in people with kidney disease or cancer. Blood transfusions may be used in cases of massive blood loss. Removal of the spleen may prevent blood cells from being removed from the circulation of the blood or destroyed too rapidly.