Definition

Sickle cell disease (SCD) is a blood disorder. Some red blood cells (RBCs) change to a sickle (crescent moon) shape. The sickle RBCs can block blood flow in blood vessels. This will slow or stop the flow of blood and oxygen to tissues and organs.

The body also destroys the sickle RBCs. Low levels of RBCs is a condition called anemia. This makes it harder for the body to get the oxygen it needs.

SCD can range from mild to severe and life-threatening.

Red Blood Cells: Normal and Sickle

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Causes

A defect in the genes causes SDC. This gene causes a problem with a part of the RBC called hemoglobin.

Parents pass the defect to their children. A person can only develop SCD if they get the defective gene from both parents.

If a person gets one defective gene, they will not have SCD. But, they can pass this gene on to their children.

Risk Factors

Sickle cell disease is most common in people who are Black or have with African ancestry.

Other backgrounds with high risk are Hispanic, Asian Indian, Middle Eastern, and southern European.

Symptoms

Symptoms may be noticed as early as 6 months old. They are different in everyone depending on where problems are in the body. The most common are:

• Tiredness—caused by anemia
• Painful swelling of hands and feet
• Yellowing of the skin and eyes— jaundice
• Belly pain
• Pale skin

Signs of acute chest syndrome (ACS) are:

• Cough
• Fever
• Breathing problems
• Chest pain
• Fast heart rate

SDC crisis may cause:

• Sudden pain—mainly in the back, chest, arms, or legs
• Pain may be throbbing or sharp
• Pain may be in one place or move around

SCD may cause other serious problems. Examples are a stroke, or painful erections lasting 4 hours or more. These problems need care right away.

Diagnosis

All newborns have a screening test at birth. Blood tests will show the sickle shaped RBCs and other problems that indicate SCD. The doctor may also do a physical exam and genetic testing.

Treatment

The goal is to ease symptoms and lower the risk of health problems. If pain crises or problems from SCD are severe, hospital care will be needed.

Treatment options may include:

• Medicines, such as:
  • Hydroxyurea—to help the body produce more red blood cells and to lower the risk of problems
  • L-glutamine—to help lower the number of pain crises
  • Voxelotor—to help reduce anemia
  • Crizanlizumab—an injection to lower the number of pain crises
  • Penicillin—given to children up to age 5, to prevent certain infections
  • Prescription or over-the-counter pain medicines
• Vaccines—to lower the risk of certain infections
• Blood transfusions—to treat anemia
• Hematopoietic stem cell transplantation (HSCT)—to cure SCD—it is not right for everyone
• Healthy habits such as rest, healthy diet, and fluids—to ease or lower the risk of pain crises

More treatments may be needed. It depends on how SCD affects the body.

Prevention

There is no way to prevent sickle cell disease. If planning a family, people at high risk may consider genetic testing.