Sickle cell disease (SCD) is a disease of the blood that affects how oxygen travels to different organs of the body. This condition can affect every organ, causing pain and other serious health problems such as infection, acute chest syndrome, and stroke.
Maureen Okam Achebe, MD, MPH, a Mass General Brigham hematologist, answers patients’ most common questions about sickle cell disease. Dr. Achebe is clinical director for hematology at Brigham and Women's Hospital. She also treats patients at Brigham and Women's Faulkner Hospital.
Sickle cell disease is caused by an abnormal hemoglobin. Hemoglobin is the protein in red blood cells that carries oxygen to different parts of the body. Sickle cell disease mostly affects people of African heritage, primarily African Americans in the United States, but it can affect anyone.
Sickle cell disease runs in families when parents pass an abnormal sickle cell gene to their child. A baby has to inherit the sickle cell gene from both parents to have sickle cell disease. If a baby inherits the gene change from just one parent, the baby has sickle cell trait and the baby’s called a carrier.
If you're born in the United States with sickle cell disease, you will know at birth. All newborn babies get a newborn screening blood test that checks for the condition.
“Now, if you're not born in the United States, or if you were born before 2006, it's possible that the diagnosis wasn't made as a baby,” explains Dr. Achebe. “In that case, it's usually made when a person goes to a doctor because they're in pain. There's a simple blood test called a hemoglobin electrophoresis that can make the diagnosis of sickle cell disease.”
“The hallmark symptom of sickle cell disease is excruciating pain,” says Dr. Achebe. “Patients who have sickle cell disease have pain that comes on episodically, and without notice, and can last for any duration of time. The pain in sickle cell disease is the thing that brings people to the hospital more frequently than any other complication of sickle cell disease.”
In a person with sickle cell disease, the abnormal hemoglobin causes the red blood cells to become hard and sticky. They look like a C-shaped farm tool called a “sickle.”
As the sickled cells move through small blood vessels, they can get stuck and block blood flow throughout the body. This causes pain. A pain crisis (also called vaso-occlusive episode or VOE) can start suddenly. Pain episodes may be mild to severe. Patients with sickle cell disease may experience pain in any part of the body, but it’s often felt in the arms, legs, chest, and back.
The only therapy approved by the Food and Drug Administration (FDA) that may be able to cure SCD is a bone marrow or stem cell transplant.
Bone marrow is a soft, fatty tissue that’s inside the center of the bones. It’s where the body makes blood cells. During a bone marrow or stem cell transplant, a bone marrow transplant specialist takes healthy normal cells that form blood from one person (a donor) and put them into someone whose bone marrow produces abnormal ‘sickle’ cells.
Bone marrow or stem cell transplants are very risky. They can have serious side effects, including death. For the transplant to work, the bone marrow from the donor must be a close match to patient’s bone marrow. Usually, the best donor is a brother or sister. Bone marrow or stem cell transplants are most common in cases of severe sickle cell disease in children. These patients typically have minimal organ damage from the disease.
Sickle cell disease management involves lifestyle modifications and medications.
“When patients are admitted to the hospital for pain episodes, they usually get fluids and pain medication,” says Dr. Achebe. “There are four medications that are currently available and your doctor can tell you which of these is best for you. Some recommendations I give my patients are to keep well hydrated, not to expose themselves to cold or too much heat, and to only exercise in a limited fashion. Most patients, by the time they're adults, have a good sense of how much exercise they can tolerate in order not to get sick.”