342 Anatomy & Physiology Essentials Copyright Goodheart-Willcox Co., Inc. Chelation therapy is a procedure that removes excess metals, such as iron, from the blood. In many cases, chelation therapy is essential for preventing organ damage and failure in patients with thalassemia. During this therapy, the chelating drug is pumped into the body either intravenously (through an IV) or subcutaneously (by injection). It then binds with whatever metal is present in excess amounts. People with thalassemia require frequent blood transfusions to increase their RBC counts. However, these transfusions can be dangerous because they can increase the iron in the blood to toxic levels. Excessive amounts of iron are especially harmful to the heart, liver, and endocrine organs. Iron accumulation leads to heart attack and death in 50% of people with thalassemia before they reach 35 years of age. Normal red blood cell (RBC) RBCs flow freely Sickle cells blocking blood flow Sticky sickle cells Cross section of RBC Cross section of sickle cell Normal hemoglobin Abnormal hemoglobin forms strands, causing the sickle, or crescent shape A Normal red blood cells B Abnormal red blood cells (sickle cells) © Body Scientific International Figure 11.17 Sickle-shaped red blood cells get stuck more easily in smaller blood vessels, causing painful episodes called crises. Extending Life Expectancy of Patients with Sickle Cell Anemia People with sickle cell anemia are prone to life- threatening infections, fatigue, and painful crises. Historically, this has meant that people with sickle cell anemia have a shortened life span. In the 1960s, 15% of children born with sickle cell anemia died before two years of age, and many more died as teenagers. Since that time, research funded by the National Heart, Lung, and Blood Institute (NHLBI) has shown that infants with sickle cell anemia who are given daily doses of penicillin have an 84% reduction in infections, which greatly improves their life expectancy. Because sickle-shaped RBCs can become lodged in the blood vessels of the brain, people with sickle cell anemia are prone to stroke. NHLBI-funded research has led to the development of the Transcranial Doppler (TCD) screening test, which can identify whether or not a patient with sickle cell anemia is at risk for stroke. Frequent blood transfusions have proven to lower these patients’ risk of stroke and increase their life expectancy. In another effort to increase the life expectancy of patients with sickle cell anemia, NHLBI researchers performed a partial stem cell transplant on ten individuals with severe sickle cell disease nine of them were cured. Research continues with the goal of finding a permanent cure for sickle cell anemia. Meanwhile, a disease that was once associated with an early death is now a manageable condition, with life expectancies ranging from 40 to 50 years of age and beyond. Research Notes Ch11.indd 342 5/3/2019 9:44:37 AM