Sickle Cell Anemia

Medically Reviewed By William C. Lloyd III, MD, FACS

What is sickle cell anemia?

Sickle cell anemia is a hereditary disease in which red blood cells are shaped like sickles rather than disks. Sickle cell anemia arises from a mutation in the hemoglobin gene that causes the blood cells to assume an abnormal shape. Sickle-shaped red blood cells have trouble passing through the smallest blood vessels and deliver less oxygen to the tissues of the body. They also increase the risk of blood clots.

An estimated two million Americans have at least one copy of the sickle cell gene. Sickle cell anemia is most common in people of African or Mediterranean heritage and is also seen in people of South American, Central American, Caribbean, and Middle Eastern ancestry (Source: NHLBI).

Symptoms, which range from infrequent and mild to severe and long term, begin to develop in late infancy. Symptoms include attacks of pain, difficulty breathing, fatigue, paleness, jaundice, and even strokes. These attacks of symptoms, called crises, are often severe enough to require hospitalization and can lead to long-term complications.

Although there is currently no cure for sickle cell anemia, its symptoms can be managed. Common treatments include folic acid supplements, pain medication, and fluid supplements, as well as vaccines and antibiotics to control infections. Blood transfusions may be given for severe crises. Sickle cell anemia has many possible complications, including infections, damage to organs, and psychological complications, all of which may require medical intervention. However, with current medical treatments, people with sickle cell anemia can expect to live full lives.

Emergency attention is needed for any severe sickle cell anemia crises or complications, including stroke. Seek immediate medical care (call 911) for symptoms of a serious crisis or serious infection, including chest pain, confusion or loss of consciousness for even a brief moment, sudden muscle weakness or paralysis, difficulty breathing, high fever, or changes in speech or vision.

Seek prompt medical treatment for symptoms of infection, including fever, aches and fatigue.

What are the symptoms of sickle cell anemia?

Symptoms of sickle cell anemia include acute symptoms related to crises, including chest, bone, and abdominal pain, rapid heart rate (tachycardia), fatigue, fever, excessive thirst, and difficulty breathing. Other, longer-term symptoms include paleness, ulcers on the legs, jaundice, delayed puberty, and blindness. In some cases, sickle cell anemia can lead to stroke.

Common symptoms of sickle cell anemia

You may experience sickle cell anemia symptoms daily or just once in a while. At times, any of these symptoms can be severe:

  • Abdominal or chest pain or pressure
  • Bone pain
  • Delayed puberty
  • Excessive thirst
  • Fatigue
  • Fever and chills
  • Frequent urination
  • Loss of vision of changes in vision
  • Rapid heart rate (tachycardia)
  • Spontaneous, painful and persistent erections (priapism)
  • Symptoms of anemia, such as dizziness, headaches, and poor circulation
  • Ulcers of the legs and skin
  • Yellowing of the skin and whites of the eyes (jaundice)

Serious symptoms that might indicate a life-threatening condition

In some cases, the crises of sickle cell anemia can be life threatening. Seek immediate medical care (call 911) if you, or someone you are with, have any of these life-threatening symptoms including:

What causes sickle cell anemia?

Sickle cell anemia is a genetic condition inherited from both parents. Mutations in the gene that controls the body’s production of hemoglobin cause an abnormal form of the protein, called hemoglobin S, which leads to malformed red blood cells. These sickle-shaped red blood cells are less effective than the normal disk-shaped cells at circulating oxygen throughout the body. Sickle cells are also more fragile than normal red blood cells, leading to an increased risk of blood clots and increased cellular breakdown.

In some cases, only one copy of the mutated gene is present. This leads to a condition known as sickle cell trait, present in about one in 12 African Americans. People with sickle cell trait have some sickle-shaped cells without the symptoms of sickle cell anemia. In fact, sickle cell trait is thought to be protective against malaria infection. People with sickle cell trait or from high-risk populations may benefit from genetic counseling when planning a family.

What are the risk factors for sickle cell anemia?

A number of factors increase your risk of developing sickle cell anemia. Not all people with risk factors will get sickle cell anemia. Risk factors for sickle cell anemia include:

  • African ancestry
  • Caribbean ancestry
  • Family history of sickle cell anemia or sickle cell trait
  • Indian ancestry
  • Mediterranean ancestry
  • Middle Eastern ancestry
  • Severe infections
  • Sickle trait
  • South or Central American ancestry

Reducing your risk of sickle cell anemia

Although sickle cell anemia is hereditary, and you cannot prevent development of the disease, you may be able to reduce your risk of sickle cell crises and complications by:

  • Avoiding alcohol and tobacco
  • Avoiding certain medications such as high-dose estrogen oral contraceptives
  • Avoiding high altitude areas
  • Avoiding physical, emotional and environmental stress
  • Consuming adequate fluids
  • Getting adequate oxygen
  • Having regular physical examinations
  • Receiving immunizations
  • Taking antibiotics when prescribed by your health care provider
  • Treating infections promptly

How is sickle cell anemia treated?

Although there is currently no certain cure for sickle cell anemia, the symptoms of a sickle cell crisis can be treated. Some people with the disease have mild and infrequent symptoms, but other individuals may have severe or even life-threatening crises. Long-term care for sickle cell anemia focuses on decreasing the frequency of crises and preventing complications. In some cases, a bone marrow transplant or stem cell therapy can provide a permanent treatment for sickle cell anemia, but neither of these treatments is an option for many people.

Treatment for sickle cell anemia crises

Treatments that may be beneficial during a sickle cell crisis include:

  • Antibiotics
  • Blood transfusions for severe cases
  • Fluid therapy given by mouth or through a vein
  • Hydroxyurea (a drug that promotes formation of a different type of hemoglobin)
  • Pain medication

Long-term treatments for sickle cell anemia

Long-term treatments are designed to reduce the number and frequency of crises, as well as to prevent the complications of sickle cell anemia.

  • Antibiotics to prevent infection
  • Blood transfusions
  • Counseling to address the stress of sickle cell anemia
  • Folic acid supplementation to assist in red blood cell production
  • Vaccines to prevent infection

Although bone marrow transplant and stem cell replacement can be effective, permanent treatments for sickle cell anemia, both of these procedures are risky and expensive and are not an option for many patients. Also, because sickle cell anemia is inherited and therefore runs in families, it is often difficult to find an unaffected and suitably matched donor for these procedures.
New medications and treatments are being studied for use in treating sickle cell anemia, including gene therapy. Much of this research is promising and may be helpful in the future for people with sickle cell anemia.

What are the potential complications of sickle cell anemia?

Because sickle cell anemia is a disease of the blood cells and affects all organ systems, there are many potential complications, which can be severe. Left untreated, complications of sickle cell anemia can be serious, even life threatening, in some cases.

You can help minimize your risk of serious complications by following the treatment plan you and your health care professional design specifically for you. Complications of sickle cell anemia include:

  • Acute chest syndrome (obstruction of blood vessels in the lungs)
  • Adverse effects of treatment
  • Anemia (low red blood cell count)
  • Blindness
  • Complicated pregnancy with high rate of fetal mortality
  • Frequent infections
  • Gallstones
  • Impotence
  • Nerve problems that cause pain, numbness or tingling
  • Organ failure or dysfunction (including kidney, liver, spleen)
  • Pulmonary embolism
  • Skin ulcerations and infections
  • Stroke
  • Transmission of disease to future generations
Was this helpful?
  1. Explore sickle cell anemia. National Heart, Lung, and Blood Institute Diseases and Conditions Index.
  2. Sickle cell anemia. Medline Plus, a service of the National Library of Medicine National Institutes of Health.
  3. Rees DC, Williams TN, Gladwin MT. Sickle-cell disease. Lancet 2010; 376:2018
  4. Bope ET, Kellerman RD (Eds.) Conn’s Current Therapy. Philadelphia: Saunders, 2013
  5. Domino FJ (Ed.) Five Minute Clinical Consult. Philadelphia: Lippincott Williams & Wilkins, 2013
Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Nov 30
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