The risk of neurological damage from stroke and recurrent stroke in children with SCD is high. The best strategy is to try to prevent strokes from occurring and recurring. Yet treatments to prevent strokes in SCD children can be extreme, so it’s important to know whether these treatments are really necessary. A number of factors in SCD children can contribute to strokes, including increased blood pressure through arteries leading to the brain, which can only be detected through Transcranial Doppler (TCD) imaging. Increased stroke risk can be as high as 40 percent for three years following abnormal TCD results.
Providing good hydration and preventing sleep apnea (abnormal stoppage of breathing during sleep) and other symptoms from SCD can help lower the risk of strokes. But research indicates that blood transfusions may do the most to prevent stroke.
The Stroke Prevention in Sickle Cell Anemia (STOP) trial has shown that simple or exchange red blood cell transfusions given every three to four weeks reduce stroke recurrence in SCD children by about 90 percent. Transfusions can be done four ways: simple, exchange, manual, and automated. The STOP trial used the simple and exchange methods. In a simple transfusion, red blood cells are given when hemoglobin levels fall, or in cases of severe anemia. An exchange transfusion involves removal of the patient’s own blood cells along with the transfusion, which can help decrease the accumulation of iron that occurs in chronic transfusion programs.
Manual transfusions are not often used. They are similar to exchange transfusions, but more tedious and time-consuming, involving removal of 500 ml of blood followed by infusion of 2 units of donor cells. Automated transfusion methods separate red blood cells from the plasma of the patient in a rapid and efficient, but costly, partial-exchange transfusion that removes blood from the patient, separates and discards the patient’s red blood cells, and returns the plasma to the patient, along with donor red blood cells.
Blood transfusions help SCD children in numerous ways. They assist the blood’s oxygen-carrying capacity and reduce the percentage of red blood cells that carry the sickle gene. Transfusions have also been shown to ease the symptoms of SCD children, such as acute chest syndrome (which can resolve dramatically following an exchange transfusion), ankle ulcers or delayed puberty, as well as life-threatening clots. Transfusions can be acute (given briefly prior to surgery), short term (to assist a healthy pregnancy), or long term (to prevent strokes).
Risks of Transfusions
Some risks of transfusions should be taken into consideration. Transfusions may require catheters or ports to be implanted in patients with poor venous access. SCD patients can acquire antibodies to the transfused blood, or develop febrile and/or hive reactions with repeated transfusions. Iron overload is a typical risk with transfusions and can compromise heart and endocrine function, requiring chelation therapy (a process that binds with the excess iron in the body so it loses its toxicity) that is not always effective. Delayed hemolytic transfusion reactions can occur in patients with antibodies, bringing on fevers, muscle aches, joint pain, anemia, even strokes and death–the very things the treatments seek to avoid.
Yet, despite the risks, blood transfusions can provide substantial benefits to children with sickle cell disease. Blood is costly and sometimes not easily available, and donors are constantly needed to keep up the supply. Please click here for more information about donating blood through the American Red Cross.