sickle cell disease, sickle cell anemia

This is a condition of the blood cells that affects mainly persons of African or mediterranean descent (Italian, Spanish, etc.). It is caused by an inherited abnormality of the oxygen carrying protein of the blood (hemoglobin). The abnormality is such that the red blood cells behave normally under normal conditions, but certain factors can cause an abnormal clumping together of the hemoglobin. When this happens the red cells assume a characteristic sickle-like shape - hence the name. These abnormal cells clog up the capillaries (smallest blood vessels) and by obstructing blood flow cause oxygen lack in the body tissues.

During such an attack of sickling (called a crisis), the patient experiences excruciating pain in various areas of the body - for example in the bones, or in the abdomen. This pain is related to poor blood flow and oxygen lack in the tissues. The abnormal red cells break down sooner than normal, causing anemia. Sometimes there is a sudden shutdown of production of the red cells - the aplastic crisis - that can cause critical anemia. The abnormal red cells tend to flow sluggishly through the smallest blood vessels (capillaries) and this may lead to damage to body tissues, even strokes.

Long term, the disease takes an inevitable toll on the body, with gradual damage to the kidneys especially - the blood cleaning filter system. Additionally, the spleen (a blood filtering organ of the immune system tucked up under the left side of the diaphragm) gradually becomes plugged up and functionally useless. This is a very dangerous situation - "functional asplenia" - because overwhelming infections can quickly develop with germs ordinarily filtered out of the bloodstream by this organ.

Treatment of sickle cell disease involves keeping the blood count up with transfusions of normal red blood cells to prevent conditions favorable for painful crises to develop, and then dealing with problems as they arise, attempting to prevent complications. Fluids and pain medications are the mainstay of treatment.

New drugs are on the horizon, however, which hold real promise for reducing the severity of the disease. Even more exciting is the prospect of bone marrow or fetal blood cell transplantation to establish a new population of normal red blood cells in the patient's body. The bone marrow transplantation procedure works but has numerous risks and side effects. Fetal cells (obtained from the umbilical cord at delivery, not by hurting the baby) can populate the bone marrow without stimulating rejection by the new host's immune system.

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