What You Should Know: Sickle Cell Disease

Sickle cell disease is an inherited blood disorder that affects red blood cells, and, subsequently the body's blood flow, oxygenation of cells and tissue, and can cause many other complications. Sickle cell disease affects millions throughout the world, though it is particularly common among people whose ancestors come from sub-Saharan Africa; Spanish-speaking regions (South America, Cuba, Central America); Saudi Arabia; India; and Mediterranean countries such as Turkey, Greece, and Italy. In the US, around 72,000 people are effected most of whose ancestors come from Africa. The disease occurs in about 1 in every 500 African-American births and 1 in every 1000 to 1400 Hispanic-American births. About 2 million Americans, or 1 in 12 African Americans, carry the sickle cell trait. While there is currently no cure, in the last 30 years, doctors have learned a lot about the disease and various ways to improve the condition of life for patients with the disease. Treatment varies with each person depending on individual symptoms.

People with sickle cell disease have red blood cells that contain an abnormal type of hemoglobin called hemoglobin S. To learn more about red blood cells, read my blog post here. Abnormal, hemoglobin S red blood cells are sickle-shaped (like a crescent moon). Sickle cells do not live as long as normal blood cells—only 16 days instead of the usual 120—and have a difficult time passing through small blood vessels. When these cells block small blood vessels, less blood can reach that part of the body and less oxygen can be carried from the lungs to cells there. Sickle cells prevent normal blow flow to tissue throughout the body, which damages the tissue and is the root of all complications of sickle cell disease. Check out this drawing of blood flow with both normal red blood cel...

There are several types of sickle disease. The most common are:
• Sickle Cell Anemia (SS)
• Sickle-Hemoglobin C Disease (SC)
• Sickle Beta-Plus Thalassemia
• Sickle Beta-Zero Thalassemia

Like most health conditions and physical traits, sickle cells are inherited. The type of hemoglobin a person's red blood cells have is dependent upon what hemoglobin he or she inherits from parents. Hemoglobin genes are inherited in two sets, one from each parent. The combination of genes determines a person's chances of having sickle cell disease or simply sickle cell trait.

Sickle Cell Trait, which not a disease in itself, is an inherited condition where both hemoglobin A and S are produced in the red blood cells. But because there is more hemoglobin A than S, it does not equate to sickle cell disease. People who have sickle cell trait are generally healthy but remain carriers of sickle cells and could pass on the trait or disease to offspring. If one parent has Sickle Cell Anemia and one parent must be "normal," all of their children will have sickle cell trait. If one parent has Sickle Cell Anemia and the other has Sickle cell Trait, there is a 50% chance every child they have will have either sickle cell disease or sickle cell trait. If both parents have sickle cell trait, there is a 25% chance for every pregnancy that their child will have sickle cell disease.

This is why it is important to know if you have sickle cell trait. To find out if you have the trait, a simple blood test followed by a lab technique called Hemoglobin Electrophoresis will test the type of hemoglobin you have. The lab technique passes an electric charge through the blood to test the hemoglobin. Because each type of hemoglobin moves a different distance depending on their composition, this determines whether you have normal hemoglobin A, sickle hemoglobin S, or other types C, D, E, etc. If planning to have children, men and women with sickle cell trait or disease might want to seek the guidance of a genetic counselor.

Because sickle cells are destroyed so rapidly within the body, people with sickle cell disease often have anemia, jaundice, and get gallstones. When sickle cells block the blood flow in vessels, numerous conditions result. People with poor blood flow also experience acute chest syndrome, pain episodes in their arms, legs, chest, back, and abdomen, as well as strokes and priapism. Some patients experience pain that lasts hours or days. Those with anemia are often constantly tired and weak and may appear pale or jaundiced. One of the most severe side-effects of sickle cell is organ-damage, which usually occurs in the spleen, kidney, or liver. When the spleen is damaged, patients become overwhelmed by certain bacterial infections.

Hopefully a person is diagnosed in infancy, and able to receive penicillin prophylaxis, vaccination against pneumococcus bacteria, and folic acid supplementation. Right now doctors cannot yet predict what future symptoms a child with sickle cells has. Babies with the disease should take penicillin from 3 months to 5 years.

For older patients, regular checkups are an important and it is essential to maintain a good relationship with a doctor who is an expert in treating sickle cell disease. Treatment for sickle cell disease complications includes a combination of antibiotics, pain management, intravenous fluids, blood transfusion, and surgery. As with patients with chronic disease, a comprehensive multi-disciplinary program of care is recommended. In addition, blood transfusions help benefit sickle cell disease patients by reducing pain crises, risk of stroke, and other complications. However, since there is no natural way for the body to eliminate iron from the blood, frequent blood transfusion cause the body to accumulate iron to the point of toxic levels. Removing iron from the body is essential because it can gather in the heart, liver, and other organs, possibly leading to organ damage. Currently there are a few treatments to eliminate the overload of iron.

While this blog post is only a brief overview, I'm going to spend more time exploring these ideas and others in future posts and in discussions in the new Sickle Cell Disease Group.

Do you know any great resources, blogs, sites, health activists or patients who are involved in the online sickle cell disease community?
What would you like to know about the disease?
Are people talking about sickle cell in your other communities? How can we spread awareness for sickle cell disease?

To learn more check out the Sickle Cell Disease Association of America Site