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Sickle cell anemia

Contents of this page:


Red blood cells, sickle cell
Red blood cells, sickle cell
Red blood cells, normal
Red blood cells, normal
Red blood cells, multiple sickle cells
Red blood cells, multiple sickle cells
Red blood cells, sickle cells
Red blood cells, sickle cells
Red blood cells, sickle and pappenheimer
Red blood cells, sickle and pappenheimer
Formed elements of blood
Formed elements of blood
Blood cells
Blood cells

Alternative Names    Return to top

Anemia - sickle cell; Hemoglobin SS disease (Hb SS); Sickle cell disease

Definition    Return to top

Sickle cell anemia is a disease passed down through families in which red blood cells form an abnormal crescent shape. (Red blood cells are normally shaped like a disc.)

Causes    Return to top

Hemoglobin is a protein inside red blood cells that carries oxygen. Sickle cell anemia is caused by an abnormal type of hemoglobin called hemoglobin S. Hemoglobin S distorts the shape of red blood cells, especially when there is low oxygen.

The distorted red blood cells are shaped like crescents or sickles. These fragile, sickle-shaped cells deliver less oxygen to the body's tissues. They also can clog more easily in small blood vessels, and break into pieces that disrupt blood flow.

Sickle cell anemia is inherited from both parents. Sickle cell disease is much more common in people of African and Mediterranean descent. It is also seen in people from South and Central America, the Caribbean, and the Middle East.

Someone who inherits the hemoglobin S gene from one parent and normal hemoglobin (A) from the other parent will have sickle cell trait. People with sickle cell trait do not have the symptoms of true sickle cell anemia.

Symptoms    Return to top

Symptoms usually don't occur until after age 4 months.

Almost all patients with sickle cell anemia have painful episodes (crises), which can last from hours to days. These crises can affect the bones of the back, the long bones, and the chest.

Some patients have one episode every few years. Others have many episodes per year. The crises can be severe enough to require a hospital stay.

Common symptoms include:

Other symptoms include:

Exams and Tests    Return to top

Tests commonly performed to diagnose and monitor patients with sickle cell anemia include:

Other tests may include:

Treatment    Return to top

Patients with sickle cell disease need ongoing treatment, even when they are not having a painful crisis. They should take supplements of folic acid (essential for producing red blood cells) because red blood cells are turned over so quickly.

The purpose of treatment is to manage and control symptoms, and to limit the frequency of crises.

During a sickle crisis, you may need certain treatments. Painful episodes are treated with pain medicines and by drinking plenty of fluids. It is important to treat the pain. Non-narcotic medications may be effective, but some patients will need narcotics.

Hydroxyurea (Hydrea) is a drug some patients use to reduce the number of pain episodes (including chest pain and difficulty breathing). It does not work for everyone.

Antibiotics and vaccines are given to prevent bacterial infections, which are common in children with sickle cell disease.

Blood transfusions are used to treat a sickle cell crisis. They may also be used on a regular basis to help prevent strokes.

Other treatments for complications may include:

Bone marrow transplants can cure sickle cell anemia. However, transplants have many risks, including infection, rejection, and graft-vs-host disease. They are not an option for most patients. Also, sickle cell anemia patients are often unable to find suitable donors.

Support Groups    Return to top

Sickle cell anemia can cause great stress to the patient and family members. Joining a support group where members share common experiences and problems can relieve this stress.

See: Sickle cell anemia - support group

Outlook (Prognosis)    Return to top

In the past, sickle-cell patients often died from organ failure between ages 20 and 40. Thanks to a better understanding and management of the disease, today patients can live into their 50s or beyond.

Causes of death include organ failure and infection. Some people with the disease experience minor, brief, infrequent episodes. Others experience severe, long-term, frequent episodes with many complications.

Possible Complications    Return to top

When to Contact a Medical Professional    Return to top

Call your health care provider if you have:

Prevention    Return to top

Sickle cell anemia can only occur when two people who carry sickle cell trait have a child together. Genetic counseling is recommended for all carriers of sickle cell trait. About 1 in 12 African Americans has sickle cell trait. It is possible to diagnose sickle cell anemia during pregnancy.

You can prevent sickling of red blood cells by:

Have physical exams every 3 - 6 months to ensure that you are getting enough nutrition and activity, and that you are receiving the proper vaccinations. Regular eye exams are also recommended.



Parents should encourage children with sickle cell anemia to lead normal lives.

To reduce sickle cell crises, take the following precautions:

Be aware of the effects that chronic, life-threatening illnesses can have on siblings, marriages, parents, and the child.

References    Return to top

Lee MT, Piomelli S, Granger S, et al. Stroke Prevention Trial in Sickle Cell Anemia (STOP): extended follow-up and final results. Blood. Aug 1, 2006;108(3):847-52.

Brawley OW, Cornelius LJ, Edwards LR, Gamble VN, Green BL, Inturrisi C, et al. National Institutes of Health Consensus Development Conference Statement: hydroxyurea treatment for sickle cell disease. Ann Intern Med. 2008;148:932-938.

Geller AK, O'Connor MK. The sickle cell crisis: a dilemma in pain relief. Mayo Clin Proc. 2008.83:320-323.

Saunthararajah Y, Vichinsky EP, Embury SH. Sickle cell disease. In: Hoffman R, Benz Jr. EJ, Shattil SJ, Furie B, Cohen HJ, eds. Hematology: Basic Principles and Practice. 4th ed. Philadelphia, Pa: Churchill Livingston;2005;chap 37.

U.S. Preventive Services Task Force. Screening for Sickle Cell Disease in Newborns: U.S. Preventive Services Task Force Recommendation Statement. Agency for Healthcare Research and Quality, Rockville, MD. Sep 2007:AHRQ Publication No. 07-05104-EF-2.

Update Date: 4/5/2009

Updated by: Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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