What is Sickle Cell Disease?
Sickle cell anemia, or sickle cell disease (SCD), is a genetic disease of the red blood cells (RBCs). Normally, RBCs are shaped like discs, which gives them the flexibility to travel through even the smallest blood vessels. However, with this disease, the RBCs have an abnormal crescent shape resembling a sickle. This makes them sticky and rigid and prone to getting trapped in small vessels, which blocks blood from reaching different parts of the body. This can cause pain and tissue damage.
SCD is an autosomal recessive condition. You need two copies of the gene to have the disease. If you have only one copy of the gene, you are said to have sickle cell trait.
Symptoms of sickle cell anemia may appear in babies as early as 4 months old, but generally occur around the 6-month mark. While there are multiple types of SCD, they all have similar symptoms, which vary in severity. These include:
• excessive fatigue or irritability, from anemia
• fussiness (in babies)
• bedwetting (from associated kidney problems)
• jaundice (yellowing of the eyes and skin)
• swelling and pain in hands and feet
• frequent infections
• pain in the chest, back, arms, or legs
The Types of SCD
Hemoglobin is the protein in red blood cells that carries oxygen. It normally has two alpha chains and two beta chains. The four main types of sickle cell anemia are caused by different mutations in these genes.
Hemoglobin SS disease
Hemoglobin SS disease is the most common type of sickle cell disease. It occurs when you inherit copies of the hemoglobin S gene from both parents. This forms hemoglobin known as Hb SS. As the most severe form of SCD, individuals with this form also experience the worst symptoms at a higher rate.
Hemoglobin SC disease
Hemoglobin SC disease is the second most common type of sickle cell disease. It occurs when you inherit the Hb C gene from one parent and the Hb S gene from the other. Individuals with Hb SC have similar symptoms to individuals with Hb SS. However, the anemia is less severe.
Hemoglobin SB+ (beta) thalassemia
Hemoglobin SB+ (beta) thalassemia affects beta globin gene production. The size of the red blood cell is reduced because less beta protein is made. If inherited with the Hb S gene, you will have hemoglobin S beta thalassemia. Symptoms are not as severe.
Hemoglobin SB 0 (Beta-zero) thalassemia
Sickle beta-zero thalassemia is the fourth type of sickle cell disease. It also involves the beta globin gene. It has similar symptoms to Hb SS anemia. However, sometimes the symptoms of beta zero thalassemia are more severe. It is associated with a poorer prognosis.
Hemoglobin SD, hemoglobin SE, and hemoglobin SO
These types of sickle cell disease are more rare and usually don’t have severe symptoms.
Sickle cell trait
People who only inherit a mutated gene (hemoglobin S) from one parent are said to have sickle cell trait. They may have no symptoms or reduced symptoms.
There are things you can do at home to help your sickle cell symptoms:
• Use heating pads for pain relief.
• Take folic acid supplements, as recommended by your doctor.
• Eat a large amount of fruits, vegetables, and whole-wheat grains. Doing so can help your body make more RBCs.
• Drink more water to reduce the chances of sickle cell crises.
• Exercise regularly and reduce stress to reduce crises
• Contact your doctor immediately if you think you have any type of infection. Early treatment of an infection may prevent a full-blown crisis.
Treatment for SCD
• Rehydration fluids through the veins helps red blood cells return to a normal state. The red blood cells are more likely to deform and assume the sickle shape if dehydrated.
• Treating underlying or associated infections is an important part of managing the crisis, as the stress of an infection can result in a sickle cell crisis. An infection may also result as a complication of a crisis.
• Blood transfusions improve transport of oxygen and nutrients as needed. Packed red cells are removed from donated blood and given to patients.
• Supplemental oxygen is given through a mask. It makes breathing easier and improves oxygen levels in the blood.
• Pain medication is used to relieve the pain during a sickle crisis. You may need over-the-counter drugs or strong prescription pain medication like morphine.
• Hydroxyurea (Droxia, Hydrea) helps to increase production of fetal hemoglobin. It could help reduce the number of blood transfusions.
• Immunizations can help prevent infections. Patients tend to have lower immunity.
Bone marrow transplant has been used to treat sickle cell anemia. Children younger than 16 years of age who have severe complications and have a matching donor are the best candidates.
In the United States, most people with sickle cell disease (SCD) are of African ancestry or identify themselves as black.
• About 1 in 13 African American babies is born with sickle cell trait.
• About 1 in every 365 black children is born with sickle cell disease.
There are also many people with this disease who come from Hispanic, southern European, Middle Eastern, or Asian Indian backgrounds.
Approximately 100,000 Americans have SCD.
-National Heart, Lung, and blood institute