Crises:

Sickle-shaped red blood cells clump more easily than normal RBCs. Sickle-cell crises start suddenly when clumping of sickled RBCs in the blood vessels obstructs the normal flow of blood, depriving various tissues and organs of oxygen. The first crises usually appear in early childhood.

Crises may be brought on by respiratory infection, by a loss of body fluids from vomiting or diarrhea, by situations in which the body's need for oxygen is increased, or they may occur for no obvious reason. They may last for several days and cause fever and sharp, intense pain in the back, abdomen, chest, arms, and legs. In infants, the hands and feet may become swollen and painful.

Crises may damage nearly any part of the body, but especially the bones, kidneys, intestines, lungs, liver, spleen, and the central nervous system, including the brain. There may also be eye damage, stroke, convulsions, or paralysis. The damage is caused because the clumping of RBCs in a blood vessel deprives tissues of oxygen.

Many people with sickle-cell disease go for long periods during which they may feel relatively well and engage in most normal activities and are free of crises (in remission). Others may experience pain on a daily basis, and some need to be hospitalized as a result of crises several times per year.

Anemia:

Sickle cells are more easily broken down and destroyed than normal RBCs. Sickle cells have a lifespan of 10 to 20 days compared to 90 to 120 days for a normal RBC. People with sickle-cell anemia thus cannot keep up a normal level of oxygen -carrying hemoglobin in their blood. This situation exists despite the fact that they make red blood cells faster than people without the disease. The result is that they are anemic.

The anemia may become so severe that a person will need to have a blood transfusion. The long-term effect of anemia is that the heart has to work harder to pump more blood through the body. Over time the heart enlarges, increasing the risk of heart attack and heart failure.

Other complications of sickle-cell disease:

People who have sickle-cell disease are more susceptible to all kinds of bacterial and fungal infections. They are more likely to have strokes and to experience kidney failure. In some people, the liver enlarges, and by age 30, 70 percent of people with sickle-cell disease have developed gallstones.

Modern medicine has increased the survival of people with sickle-cell disease. About half the people with sickle-cell disease live beyond 50 years of age. Still, living with the pain and complications of this condition can cause emotional stress on both the person with the disease and the family.

How Is Sickle-Cell Disease Diagnosed?

Sickle-cell disease and sickle-cell trait can be diagnosed by a blood test, which detects the presence of HbS and other abnormal hemoglobins. A complete blood count (CBC) counts the number of RBCs and checks for abnormal shapes.

How Is Sickle-Cell Disease Treated?

There is no cure for sickle-cell anemia. Much treatment is preventive and directed toward symptoms. Antibiotics may be given to prevent infections. Fluid intake is important to prevent dehydration, a major cause of sickling. Folic acid may be given daily to lessen the anemia by helping to make new red cells. Children are given a complete set of immunizations.

Lifestyle habits that can help sickle-cell patients stay healthy and have fewer crises include drinking plenty of water, avoiding extremes of heat and cold, avoiding stress and overexertion, getting enough sleep, and having regular medical check-ups.

Treatment in a sickle-cell crisis may require oxygen therapy, pain relieving medications, antibiotics, and intravenous fluids to offset dehydration. Blood transfusions may also have to be performed. Treatment of pain is a major concern. The benefits of different pain relievers and their unwanted side effects must be balanced for cach patient.

Rescarch is ongoing to find better ways to treat people with sickle-cell disease. Some of these research efforts are directed at stimulating the production of fetal hemoglobin, a form of hemoglobin found in infants, even those with sickle-cell disease. Other research is directed toward the development of drugs that block dehydration in cells. Gene therapy and the transplantation of healthy bone marrow that makes normal red blood cells are also under investigation.

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