This disease is an inherited blood disorder that occurs almost exclusively in blacks. It is caused by an abnormality in the pigment hemoglobin, the oxygen-carrying component of the red blood cells. The defective hemoglobin—called hemoglobin S—causes the red blood cells to become rigid and "sickle" shaped rather than flexible and round. These deformed cells are brittle and easily destroyed, leading to the symptoms of sickle-cell disease.
WHEN SHOULD I SUSPECT THAT MY CHILD HAS SICKLE-CELL ANEMIA?
All black infants should be screened for sickle-cell anemia at birth. This is particularly important if there is any history of the disease in the family. A definitive diagnosis can be made with simple blood tests.
WHAT CAUSES SICKLE-CELL ANEMIA?
Sickle-cell disorders are passed genetically from parent to child. If both parents have a gene for hemoglobin S., their child has a 25 percent chance of inheriting both genes and getting sickle-cell anemia. If only one gene is inherited, half of the child's hemoglobin will be normal and will prevent the disease from developing. These children have sickle-cell trait and are usually healthy; however, they can pass on the abnormal gene to their children. One in 12 blacks are healthy carriers of the sickle-cell gene.
HOW DOES SICKLE-CELL ANEMIA DEVELOP?
Although the abnormal hemoglobin can be detected at birth, symptoms of sickle-cell anemia generally do not appear until the infant is about six months old. These symptoms include delayed growth and development and anemia, which causes fatigue, pallor and increased susceptibility to infection. The first noticeable sign of the disease may be a painful attack known as a sickle-cell crisis. Such an episode often follows an infection or injury and affects various parts of the body, particularly the abdomen, long bones, joints and chest. Vision problems can occur when the retina is affected. The severity and frequency of crises can vary tremendously.
WHAT CAUSES A SICKLE-CELL CRISIS?
The body manufactures red blood cells continually. Healthy red blood cells are disk-shaped and flexible, so they can circulate freely through the capillaries and other small blood vessels. After about 120 days, they are destroyed and replaced with new ones. In sickle-cell anemia, the red blood cells have a shortened life span of only two weeks or so.
The result is a low red blood cell count and chronic anemia. Moreover, in contrast to normal red blood cells, the rigid sickle cells cannot pass easily through tiny blood vessels. Impaired circulation leads to slower oxygen transport, which worsens sickling. This cycle can eventually interrupt blood flow to the tissues and organs, causing pain. This is a sickle-cell crisis.
WHAT TREATMENTS ARE AVAILABLE?
There is no cure for sickle-cell anemia, but with your doctor's help, you can ease the discomfort of most crises and help prevent others. Moderate crises can be managed with medication to relieve pain and prevent dehydration. During more severe crises, oxygen may be given if your child's blood does not have enough. A blood transfusion before any medical or dental surgery can provide your child with healthy red blood cells, thus avoiding the crisis that might otherwise follow.
Black parents should make sure their infants are screened at birth. Early identification and treatment can minimize potential complications. Antisickle drugs are being tested, but, at present, genetic testing and counseling are the only means of preventing sickle-cell anemia from being passed to a new generation.
THE DANGERS OF HIGH-ALTITUDE TRAVEL
If your child has sickle-cell anemia, she will have to be cautious about high altitudes and air travel throughout life. The body normally compensates for reduced oxygen due to high altitudes and changes in air pressure in airplanes by increasing the amount of circulating red blood cells and hemoglobin. However, in a child with sickle-cell anemia, this could lead to an increase in abnormal hemoglobin and precipitate a sickle-cell crisis.
The child will probably be advised to avoid traveling to places more than 6,000 feet above sea level and to be cautious when flying. Stick to commercial airlines that have pressurized cabins and an emergency supply of oxygen aboard. Some people with sickle-cell anemia require oxygen support during any flight.
COPING WITH SICKLE-CELL ANEMIA
• Make sure your child receives all appropriate vaccines to prevent infections (including pneumococcal vaccine).
• Watch for infections and administer antibiotics promptly as prescribed by your doctor.
• Talk to your doctor about treating your child with antibiotics in advance (prophylactically) to prevent serious infections.
• Give the child daily oral supplements of folic acid because the disease increases the body's need for this vitamin.
• Take appropriate precautions when traveling in airplanes or to high altitudes.
GETTING HELP
Call your doctor if your child:
• Has sickle-cell anemia and develops signs or symptoms of infection.
• Has sickle-cell anemia and is experiencing vision problems.
• Has sickle-cell anemia and is suffering from a painful crisis.
