An All-Out Challenge to Sickle Cell Anemia
A child's blood, of course, pumps to every organ. So when hemoglobin, the oxygen carrier in red blood cells, becomes distorted in sickle cell anemia, the change has implications for every part of a young patient's body.
That's why the Comprehensive Sickle Cell Center at Cincinnati Children's is attacking this inherited disorder on every front.
Early Detection Is Essential
Sickle cell anemia affects more than 70,000 Americans, primarily those of African descent. About 600 children and adults in the Cincinnati area have the disease. Some 20,000 more carry the gene but have no symptoms.
With sickle cell anemia, the abnormal hemoglobin stiffens and distorts the usually round red blood cells into sickle, or crescent, shapes. These rigid, crescent-shaped cells can plug small blood vessels and decrease blood flow to various parts of the body.
Patients can suffer bacterial infections, pulmonary complications, stroke and unpredictable pain episodes. The disease process begins shortly after birth. Symptoms can develop as early as 3 or 4 months of age.
Cincinnati Children's was one of the first to test newborns for sickle cell anemia in the late 1970s; the screening went national by the early 1990s.
With a diagnosis of sickle cell anemia, doctors prescribe penicillin to prevent the pneumococcal infections that often occur. The child continues on penicillin for five years, and parents are alerted to bring a child in for medical care on the first day of a fever.
Changing the Outcome
"Infection was once the number one killer of these patients, and now it's number three," says Karen Kalinyak, MD, clinical director of the Comprehensive Sickle Cell Center.
Pulmonary complications are now at the top, and, "There's a lot of research on how to prevent acute chest syndrome," Dr. Kalinyak says. Untreated, these complications can lead to pulmonary hypertension and chronic lung disease. Cincinnati Children's developed the current standard of care: incentive spirometry, a regimen of deep breathing using a spirometer to measure lung capacity. In a randomized clinical trial of patients hospitalized for pain, aggressive use of the incentive spirometer successfully prevented acute chest syndrome.
Stroke is another serious threat. "In the natural course of the disease, about 10 percent of young patients will have a stroke by age 15," Dr. Kalinyak says. "If we used MRIs, we would see that 10 to 20 percent more have had silent strokes."
To identify children at high risk for stroke, Cincinnati Children's participated in a national study using transcranial Doppler, a painless ultrasound, to measure blood-flow speed in the brain. Children at risk were then given transfusions, which decreased the incidence of stroke.
Another new medicine, hydroxyurea, helps reduce the rate of pain episodes by half, and decreases the need for transfusion.
Hope for a Cure
Cincinnati Children's was also on the leading edge of the only cure now available, performing the first bone marrow transplant for sickle cell anemia. Candidates must have significant disease and a perfectly matched bone marrow donor. The cure rate is 85 percent. The center has performed two bone marrow transplants and plans a third this summer.
Looking forward, gene therapy holds promise for sickle cell anemia. It is the first disease associated with a single gene mutation. Researchers at Cincinnati Children's are striving to alter that gene and eliminate the disease.
"It's important for families to know that we're working to be ahead of the game and to prevent many of the symptoms," says Dr. Kalinyak. "We want to identify stroke risk early and learn how best to intervene, and to decrease the number of pain episodes. We want to improve both the quality and duration of a patient's life, and ultimately cure this disease in every patient."
