Sickle cell anemia is a disease passed down through families. The red blood cells that are normally shaped like a disc take on a sickle or crescent shape. Red blood cells carry oxygen throughout the body.

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

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 red blood cells. The red blood cells become fragile and shaped like crescents or sickles.
• The abnormal cells deliver less oxygen to the body's tissues.
• They can also easily get stuck in small blood vessels and break into pieces. This can interrupt healthy blood flow and cut down even more on the amount of oxygen flowing to body tissues.

Sickle cell anemia is inherited from both parents. If you get the sickle cell gene from only one 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 usually do not occur until after the age of 4 months.

Almost all people with sickle cell anemia have painful episodes called crises. These can last from hours to days. Crises can cause pain in the lower back, leg, joints, and chest.

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

When the anemia becomes more severe, symptoms may include:

• Fatigue
• Paleness
• Rapid heart rate
• Shortness of breath
• Yellowing of the eyes and skin (jaundice)

Younger children with sickle cell anemia have attacks of abdominal pain.

The following symptoms may occur because small blood vessels become blocked by the abnormal cells:

• Painful and prolonged erection (priapism)
• Poor eyesight or blindness
• Problems with thinking or confusion caused by small strokes
• Ulcers on the lower legs (in adolescents and adults)

Over time, the spleen stops working. As a result, people with sickle cell anemia may have symptoms of infections such as:

• Bone infection (osteomyelitis)
• Gallbladder infection (cholecystitis)
• Lung infection (pneumonia)
• Urinary tract infection

Other signs and symptoms include:

• Delayed growth and puberty
• Painful joints caused by arthritis
• Heart failure due to too much iron (from blood transfusions)

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

• Bilirubin
• Blood oxygen saturation
• Complete blood count (CBC)
• Hemoglobin electrophoresis
• Serum creatinine
• Serum potassium
• Sickle cell test

The goal of treatment is to manage and control symptoms, and to limit the number of crises. People with sickle cell disease need ongoing treatment, even when not having a crisis.

People with this condition should take folic acid supplements. Folic acid helps make new red blood cells.

Treatment for a sickle cell crisis includes:

• Blood transfusions (may also be given regularly to prevent stroke)
• Pain medicines
• Plenty of fluids

Other treatments for sickle cell anemia may include:

• Hydroxyurea (Hydrea), which helps reduce the number of pain episodes (including chest pain and breathing problems) in some people
• Antibiotics, which help prevent bacterial infections that are common in children with sickle cell disease
• Medicines that reduce the amount of iron in the body.

Treatments that may be needed to manage complications of sickle cell anemia include:

• Dialysis or kidney transplant for kidney disease
• Counseling for psychological complications
• Gallbladder removal in people with gallstone disease
• Hip replacement for avascular necrosis of the hip
• Surgery for eye problems
• Treatment for overuse or abuse of narcotic pain medicines
• Wound care for leg ulcers

Bone marrow or stem cell transplants can cure sickle cell anemia, but this treatment is not an option for most people. Sickle cell anemia patients often cannot find well-matched stem cell donors.

People with sickle cell disease should have the following vaccinations to lower the risk of infection:

• Haemophilus influenzae vaccine (Hib)
• Pneumococcal conjugate vaccine (PCV)
• Pneumococcal polysaccharide vaccine (PPV)

Joining a support group where members share common issues can relieve the stress of a chronic disease.

In the past, people with sickle cell disease often died between ages 20 and 40. Thanks to a better care, people now can live to the age of 50 and beyond.

Causes of death include organ failure and infection.

Call your health care provider if you have:

• Any symptoms of infection (fever, body aches, headache, fatigue)
• Pain crises
• Painful and long-term erection (in men)

DeBaun MR, Frei-Jones M, Vichinsky E. Hemoglobinopathies. In: Kliegman RM, Stanton BF, St. Geme JW III, et al., eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 456.

Saunthararajah Y, Vichinsky EP. Sickle cell disease: clinical features and management. In: Hoffman R, Benz EJ Jr, Silberstein LE, et al., eds. Hematology: Basic Principles and Practice. 6th ed. Philadelphia, Pa: Elsevier Saunders; 2012:chap 40.

Rees DC, Williams TN, Gladwin MT. Sickle-cell disease. Lancet. 2010;376(9757):2018-2031.