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, incidence, and risk factors
Sickle cell anemia is caused by an abnormal type of hemoglobin called hemoglobin S. Hemoglobin is a protein inside red blood cells that carries oxygen. Hemoglobin S changes the shape of red blood cells, especially when the cells are exposed to low oxygen levels. The red blood cells become shaped like crescents or sickles.
The fragile, sickle-shaped cells deliver less oxygen to the body's tissues. They can also get stuck more easily in small blood vessels, and break into pieces that interupt healthy blood flow.
Sickle cell anemia is inherited from both parents. If you inherit the hemoglobin S gene from one parent and normal hemoglobin (A) from your other parent, you will have sickle cell trait. People with sickle cell trait do not have the symptoms of sickle cell anemia.
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.
Symptoms
Symptoms usually don't occur until after age 4 months.
Almost all patients with sickle cell anemia have painful episodes (called 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:
Signs and tests
Tests commonly performed to diagnose and monitor patients with sickle cell anemia include:
Other tests may include:
Treatment
The goal of treatment is to manage and control symptoms, and to limit the number of crises.
Patients with sickle cell disease need ongoing treatment, even when they are not having a painful crisis.
Folic acid supplements should be taken. Folic acid is needed to make red blood cells.
Treatment for a sickle cell crisis includes:
Other treatments for sickle cell anemia may include:
Hydroxyurea (Hydrea), a medicine that may help reduce the number of pain episodes (including chest pain and difficulty breathing) in some people
Antibiotics to prevent bacterial infections, which are common in children with sickle cell disease
Treatments for complications of sickle cell anemia may include:
Kidney dialysis or kidney transplant for kidney disease
Drug rehabilitation and counseling for psychological complications
Gallbladder removal in those with gallstone disease
Hip replacement for avascular necrosis of the hip
Treatments, including surgery, for persistent, painful erections (priapism)
Surgery for eye problems
Wound care, zinc oxide, or surgery for leg ulcers
Bone marrow or stem cell transplants can cure sickle cell anemia. However, they are current not an option for most patients. Sickle cell anemia patients are often unable to find well-matched donors.
Support Groups
Joining a support group where members share common experiences can relieve the stress related to caring for someone with a chronic disease. See: Sickle cell anemia - support group
Expectations (prognosis)
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.
Calling your health care provider
Call your health care provider if you have:
Prevention
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.
If you have sickle cell anermia, you can prevent the change in red blood cell shape by:
Have a physical exam every 3 - 6 months to make sure that you are getting enough nutrition and activity, and that you are receiving the proper vaccinations. Regular eye exams are recommended.
PREVENTING CRISES
It is important to maintain good oxygen levels and to prevent dehydration. The following steps can help prevent a sickle cell crisis:
Avoid strenous activities, stress, smoking, high-altitudes, nonpressurized flights, and other events that reduce your oxygen level
Always have plenty of fluids with you
Avoid too much sun exposure
Consider having the child with sickle cell anemia wear a Medic Alert bracelet. Share the above information with teachers and other caretakers, when necessary.
PREVENTING INFECTIONS
References
- Lee MT, Piomelli S, Granger S, et al. Stroke prevention trial in sickle cell anemia (STOP): extended follow-up and final results. Blood. 2006;108:847-852.
- 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.
- Hebbel RP. Pathobiology of sickle cell disease. In: Hoffman R, Benz EJ, Shattil SS, et al., eds. Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone;2008:chap 42.
- Saunthararajah Y, Vichinsky EP, Embury SH. Sickle cell disease. Clinical features and management. In: Hoffman R, Benz Jr. EJ, Shattil SS, eds. Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Churchill Livingston; 2008:chap 43.
- 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.
