Difference Between Anemia and Leukemia
In some cases, the red blood cells are seriously reduced in number or are deficient in hemoglobin. This condition is known as anemia, or, more correctly, the anemias. Because of the hemoglobin deficiency, a reduced amount of oxygen reaches the tissues, and the cells cannot function normally. The symptoms of anemia include paleness, fatigue, headache, general weakness, black spots before the eyes, palpitation of the heart, and an increased pulse rate. In severe cases, breathing may be shallow and difficult. Occasionally, there is an excessive amount of water in the tissues. This is usually due to poor circulation, since the heart muscle is not getting enough oxygen. In some instances, a person may be anemic without displaying any of these symptoms.
There are various types of anemias. The nutritional anemias are due to a malfunction in the blood-forming centers. The diet may not provide enough of the materials necessary for blood formation, or the body may not be able to use those materials. For example, a lack of iron in the blood can cause an iron-deficiency anemia to develop. In this condition the red blood cells are smaller, reduced in number, and contain less hemoglobin than is normal. They are unable to carry enough oxygen to the cells, which leads to oxygen deficiency in the tissues. Women are particularly likely to develop this kind of anemia. Another nutritional anemia, causing similar symptoms, is achlorhydric anemia. In this disease the stomach does not secrete enough hydrochloric acid. This prevents absorption of iron, even though there may be enough in the diet.
In hemolytic anemias, the circulating red blood cells are destroyed too quickly. This can be either an inherited or acquired characteristic. It may also be due to spleen overactivity, the effects of certain poisons, or the fragility of the red blood cells.
Sickle-cell anemia is a hereditary condition in which an abnormal hemoglobin causes red blood cells to deform into a crescent shape. Such cells die faster than they can be replaced, so there are not enough of them to carry oxygen.
Certain anemias are secondary—that is, they result from some underlying condition, which may or may not be clearly defined. Such anemias may be a consequence of hemorrhage, chronic blood loss, acute infection, malignant growths, gastrointestinal disease, or damage to the liver. X rays and various toxic and radioactive substances may cripple the bone marrow so that it is unable to produce an adequate number of red blood cells.
A rather serious disorder, polycythemia is characterized by an overproduction of red blood cells. The blood becomes too thick and moves through the veins sluggishly. The patient complains of headaches and dizziness. Blood tends to form clots in the blood vessels. If these clots drift around in the veins and arteries, gangrene, or tissue death, may develop. Clots that block a vessel in the heart or brain can cause death.
In some illnesses the body produces too many white blood cells. This is sometimes due to the disease known as leukemia, in which the white-blood-cell count may run as high as 500,000 per cubic millimeter. The white blood cells overrun the bone marrow, crowd out the red-blood-cell- and platelet-producing material, and cause an accompanying anemia to develop. Lymph nodes and reticuloendothelial tissue swell with their burden of excessive white blood cells. Leukemia is believed to be due to an abnormal condition of the bone marrow or lymphoid tissue, causing white-cell-forming elements to multiply.
Leukemia has long received attention from medical researchers, and substantial progress has been made against the effects of the disease. Treatments can slow down the course of certain forms of leukemia, particularly types that respond well to chemotherapy, which uses toxic chemicals to kill the leukemic cells, and bone-marrow transplantation, which replaces the patient’s defective marrow with marrow from a healthy donor. Finding a compatible donor is often difficult, however, so researchers have developed a technique that allows the patient’s own bone marrow to be removed. He or she then receives high doses of chemotherapy, after which the marrow is reintroduced to the bones. This is called autologous transplantation.