Sickle Cell Anemia

What is sickle cell anemia?

Sickle cell anemia is a blood disease that causes abnormal red blood cells. Africans, African Americans, and East Indians have a high risk of the disease. This is also true for people from the Mediterranean (Italian or Greek), Middle East, Caribbean, and Central or South America. In the US, 1 of every 12 African-American newborns carries the sickle cell trait in his or her genes. About 1 of every 500 African American newborns has this lifelong 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. If a child inherits a sickle cell gene from each parent, the child has 2 genes and will have sickle cell anemia. If the child inherits the gene from just one parent, the child will not have the disease. However, he or she is a carrier and could pass the gene to his or her children.

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 have an abnormal type of hemoglobin called hemoglobin S. The abnormal hemoglobin can change the shape of the red blood cells. Instead of being soft and round, the cells are a stiff crescent (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. It can also cause severe pain and fever.

The abnormal blood cells are fragile and have a much shorter life than normal red blood cells. Your body may not be able to make new red blood cells fast enough. This can cause a shortage of red blood cells. The 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 2 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?

Babies are born with a kind of hemoglobin that protects the red blood cells from sickling. Around 4 to 5 months old, this hemoglobin is replaced by "adult" hemoglobin and the cells start to sickle. After 4 months of age, symptoms are often brought on by an infection. The symptoms may include:

• fever
• swelling of the hands and feet
• joint pain
• abdominal pain
• symptoms of anemia, such as tiredness, pale skin color, and dizziness

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. Times when you have no symptoms are called remissions.

Sickle cell anemia can cause your skin to look pale as the 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. A 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?

In the US, sickle cell anemia is usually diagnosed at birth after an abnormal result from a newborn screening test. Another blood test called hemoglobin electrophoresis is then done for final diagnosis. This test can also find people who carry the gene for sickle cell anemia.

If sickle cell anemia is suspected in someone who did not have a newborn screen, a blood test called a complete blood count (CBC) may be done. The CBC looks for anemia and sickle-shaped red blood cells. Then a hemoglobin electrophoresis test may be done.

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 during pregnancy.

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. If too many red blood cells are destroyed during the crisis, you may need a blood transfusion.

Hydroxyurea is a medicine that may be used to try to prevent sickle cell crisis. Taken daily, it decreases how often you have crises. It can also shorten how long each crisis lasts. It is still being studied, especially to see if there are any long-term side effects.

Researchers are looking for other medicines that may treat the symptoms of sickle cell anemia. They are also studying bone marrow and stem cell transplants and other techniques as possible ways to cure sickle cell disease

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 make it hard for a man to have erections (erectile dysfunction).

High blood pressure in the lungs is a common complication of sickle cell anemia. This problem is called pulmonary hypertension. It can cause trouble breathing and heart damage.

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 medical care right away.

How can I take care of myself?

If you have sickle cell anemia, it is very important for you to have a healthcare provider who is familiar with sickle cell disease—someone who knows how to treat it and how to prevent complications. You should see your provider regularly. You need to develop a good working relationship with your provider to learn how to care for yourself at home. You also need to learn which symptoms need medical care right away.

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 shots are up-to-date.
• Get a flu shot every year.
• Get a pneumococcal shot to protect against a common type of pneumonia.
• Discuss other possible shots, such as hepatitis A and B, chickenpox, and meningitis shots.
• 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.
• See if you need to take antibiotics regularly to prevent infections.

One of the most important things to do for children under the age of 5 is to give your child antibiotics every day to prevent infection. Pneumonia and other infections caused by bacteria can be deadly to a child with sickle cell disease. It also helps to keep your child away from people who have infections and to teach your child to wash his or her hands often.

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

• strenuous exercise
• cold temperatures
• high altitude
• tight clothing
• things that make the blood vessels narrower, such as:
  • some medicines
  • cigarette smoking
  • illegal drugs, such as cocaine

Also try to avoid dehydration. A loss of too much fluid from your body 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://scinfo.org/

How can sickle cell anemia be prevented?

Because sickle cell anemia is inherited, it can be prevented if couples who each carry the sickle cell trait gene do not have children. Screening tests can show if you are a carrier. When both parents are carriers, each child has a 25% risk of having sickle cell anemia and a 50% risk of being a carrier. 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. If you are African American or a member of one of the other racial or ethnic groups where the gene is common and don’t know if you are a carrier or not, you and your partner should consider being tested if you are thinking of having children.