What is sickle cell anemia?

Sickle cell anemia is an inherited disease that causes abnormal red blood cells. It is a lifelong disease.

Sickle cell anemia is most prevalent among people who are African, African American, Mediterranean (Italian or Greek), Middle Eastern, East Indian, Caribbean, and Central or South American. In the US, 1 of every 12 African-American newborns carries the sickle cell trait in his or her genes. About 1 of every 400 newborns has the disease.

How does it occur?

Sickle cell anemia is inherited. If a baby's parents have the disease or both are carriers, the baby may inherit the sickle cell genes from the parents. If a baby inherits just 1 gene for the disease, the baby will not have the disease but is a carrier of the trait. If a child inherits a sickle cell gene from each parent, the child has 2 genes and will have sickle cell anemia.

The red blood cells carry oxygen from your lungs to the rest of your body. A chemical in the red blood cells called hemoglobin helps the cells carry oxygen. If you have sickle cell anemia, most of your red blood cells contain an abnormal type of hemoglobin called hemoglobin S. This abnormal hemoglobin can change the shape of the red blood cells from soft and round to a stiff crescent, or sickle, shape. This shape makes it harder for the cells to pass through small blood vessels. The cells can get stuck in blood vessels and block the flow of blood and oxygen to parts of the body. The lack of oxygen can damage the body tissues and cause severe pain and fever.

These abnormal blood cells are fragile and have a much shorter life than normal red blood cells. A shortage of red blood cells can occur because sickle cells do not last very long and it is hard for your body to make new red blood cells fast enough. This shortage of red blood cells is called anemia.

Sickle cell anemia is one of 3 common types of sickle cell disease in the US. The other two types are called hemoglobin SC disease and sickle thalassemia. The 3 conditions differ in the types and amounts of abnormal hemoglobin in the blood.

What are the symptoms?

The first symptoms of sickle cell anemia may not appear until a child is about 1 year old. They are often brought on by a viral infection. The symptoms may include fever, swelling of the hands and feet, and joint or abdominal pain. Toddlers and children may have frequent pain with or without any other signs of illness.

Most children and adults with sickle cell anemia have times when they have symptoms and times when they do not have symptoms. Crises are the times when abnormal red blood cells block the flow of blood, causing symptoms. The most common symptom of a sickle cell crisis is pain. The pain is usually felt in the part of the body where the sickling cells are blocking blood flow. Crises may start suddenly and last from a few days to several weeks. The periods of no symptoms are called remissions.

Sickle cell anemia can cause your skin to appear pale as anemia worsens. The paleness may be most obvious on the inside of your eyelids, under fingernails, and in the creases of the palms of your hands. Your skin may also turn yellow (become jaundiced).

One of the life-threatening complications of sickle cell anemia can be anemia that is sudden and severe. This severe shortage of normal red blood cells may cause weakness, shortness of breath, or even heart failure. The symptoms of shock caused by heart failure are low blood pressure, rapid pulse, and decreasing consciousness.

How is it diagnosed?

Sickle cell anemia should be diagnosed as early as possible, preferably at birth. Most states in the US require a blood test for sickle cell anemia at birth. Sickle cell anemia can be diagnosed before birth with DNA testing of a baby's cells. The cells can be obtained with amniocentesis or chorionic villus sampling.

A blood test called hemoglobin electrophoresis can be done to test for sickle cell anemia. It can also be used to find carriers of the sickle cell trait.

A complete blood count (CBC) may be done to look for anemia, sickle-shaped red blood cells, or other complications of sickle cell anemia.

How is it treated?

If you have a sickle cell crisis, you will be given IV fluids and pain medicine. You will need to rest. So many red blood cells may be destroyed during the crisis that you may need a blood transfusion.

Hydroxyurea is a drug now being used to try to prevent sickle cell crisis. It is taken daily and decreases the number of days of sickle cell crises in most people. It is still being studied, especially to see if there are any long-term side effects.

Researchers are studying bone marrow transplants as a possible treatment.

What are the complications of sickle cell anemia?

Because abnormal red blood cells are circulating throughout your body, problems can occur in any part of your body. Possible problems are:

• infections such as pneumonia or meningitis
• kidney infections
• bone infections
• gallstones
• loss of vision caused by damage to blood vessels in the eyes
• hip and shoulder joint damage
• stroke
• damage to tissues in the penis, which may eventually may make it hard for a man to have erections (erectile dysfunction).

Acute chest syndrome is another possible problem. Acute chest syndrome happens when there is sickling of red blood cells in the lungs. The usual symptoms are fever and chest pain and sometimes shortness of breath. Like infections and stroke, it can be life threatening and needs immediate medical attention.

How can I take care of myself?

If you have sickle cell anemia, it is very important for you to see your health care provider regularly. You need to develop a good working relationship with your provider to learn how to care for yourself at home. You will also learn which symptoms require immediate medical care.

People with sickle cell anemia are more likely to have serious infections, ranging from flu to pneumonia. Prevention of infections is an important part of the treatment because they can cause a sickle cell crisis. To help prevent infections you should check with your provider to:

• Make sure all of your immunization shots are up-to-date.
• Get a flu shot every year.
• Get the pneumococcal shot to protect against a common type of pneumonia.
• Discuss other possible shots, including hepatitis A and B, chickenpox, and meningococcus vaccines.
• See if you need to take antibiotics regularly to prevent infections.
• See if you should take a daily multiple vitamin to help your body make new red blood cells.
• See if symptoms of illness or injury need immediate treatment. You may be given IV fluids (to prevent dehydration) and oxygen. This may help prevent sickling of the red blood cells.

To try to prevent sickle cell crises, it can be helpful to avoid conditions that lower the blood oxygen, such as:

• strenuous exercise
• cold temperatures
• high altitude
• tight clothing
• medicines and illegal drugs, such as cocaine, that constrict blood vessels.

Also try to avoid dehydration (a loss of too much fluid from your body), which can cause sickling.

For more information, contact:

Sickle Cell Disease Association of America
Phone: (800) 421-8453
Web site: http://www.sicklecelldisease.org.

Sickle Cell Information Center
Phone: (404) 616-3572
Web site: http://www.scinfo.org

How can sickle cell anemia be prevented?

Because sickle cell anemia is inherited, it can be prevented if couples who both carry the sickle cell trait gene do not have children. When both parents are carriers, each child has a 25% risk of having sickle cell anemia and a 50% risk of being a carrier.

Screening programs are available to identify sickle trait carriers. If you are thinking about having a child and have sickle cell anemia or are a carrier, it is a good idea to seek genetic counseling.