Sickle Cell Anemia
Overview
Sickle cell anemia is a genetic condition that affects hemoglobin, the part of red blood cells responsible for carrying oxygen from the lungs to the rest of the body.
Red blood cells with normal hemoglobin are round, smooth and flexible, allowing them to easily flow through blood vessels. In sickle cell anemia patients, the hemoglobin is abnormally shaped and sticks together, causing the red blood cells to become stiff and crescent, or sickle, shaped.
These sickle-shaped red blood cells are more fragile and die more quickly than normally shaped red blood cells. Because the cells die faster than the body can create new ones, this creates a shortage of red blood cells.
The sickle-shaped cells also do not flow as easily through blood vessels. They are sticky and can catch on one another, causing the cells to pile up and block the blood vessel. This can cause tissue and organ damage, and sometimes stroke.
Symptoms
Sickle cell anemia is a genetic condition present from birth, with symptoms usually beginning to appear at about 4 months old.
The main symptom of the condition is low red blood cell count, a form of anemia, which often causes pale skin and nails. This also can also cause delayed growth in young patients, because the body is not receiving the oxygen and nutrients it needs.
Many of the other symptoms of the condition are caused by a blockage in the blood vessels and may include:
- Pain, often in the chest, joints or limbs
- Swelling of the hands and feet
- Vision problems
- Rarely, stroke
Patients with sickle cell anemia often experience more infections due to damage to the spleen, an organ that fights infections.
Causes and Risk Factors
Sickle cell anemia is a genetic condition passed down from parents to children. It is recessive, which means both parents must carry the gene in order for the child to have the condition. If only one of the parents has the gene, they are known as carriers of the trait. A carrier is someone who has the gene and can pass it on to his or her children, but does not develop the condition.
In the United States, the condition most commonly affects African Americans. Other populations most commonly affected include those from Africa, India, the Mediterranean region, Saudi Arabia, Caribbean islands, and Central and South America.
Diagnosis
Sickle cell anemia is diagnosed by a blood test that looks for the abnormal form of hemoglobin, known as hemoglobin-S. This test is routinely performed in the United States during a child’s newborn screening examination. It also can be performed for older children and adults if needed.
If the blood test results are positive, further laboratory tests will be performed to determine if the patient has the condition or if they are a carrier. If test results indicate the patient has sickle-cell anemia, additional tests may be performed to confirm the diagnosis.
If both parents have the sickle-cell gene, physicians can also screen for the condition before the child is born by performing an amniocentesis, which takes a sample of the amniotic fluid surrounding the fetus. This fluid can be tested for various genetic abnormalities, including sickle cell anemia.
Treatment
The only cure for sickle cell anemia is a bone marrow transplant, also known as stem cell transplant. During this procedure the patient's own bone marrow is replaced by donor bone marrow cells, which produce new red blood cells for the body.
This procedure can have serious side effects, and finding a matching donor can be challenging. Because of this, this treatment is not usually performed unless the patient is severely affected by sickle cell anemia. Otherwise, treatment will generally focus on managing the symptoms and maintaining the patient's quality of life.
Young children diagnosed with the condition are often given an antibiotic to prevent infections, such as pneumonia. Adults may also be given antibiotics to help fight off infections. Vaccinations, for adults and especially for young children, are also important to help prevent deadly infections.
Over-the-counter pain medications or home remedies, such as applying heat to the affected area, can help manage the pain some patients experience. Sometimes stronger pain medication is needed, and prescribed by their medical team.
Patients may also be given a medication to help the body create fetal hemoglobin, which is found in newborns and can prevent the formation of sickle-shaped cells. The longterm effects of this medication are still being researched, and parents should talk to their medical team to determine whether it is a good treatment plan for their child.
Since sickle cells can stick together and cause blockages in the blood vessels, special attention should be paid to the risk of stroke.
Maintaining regular appointments with their medical team is essential to each patient's treatment plan.
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