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# Sickle Cell Disease Sickle cell disease occurs almost exclusively in African Americans in the United States. It is carried by 8-10% of the population. ## Sickle Cell Variants * **Sickle Cell Trait (HbAS):** The individual has one defective S gene and one normal hemoglobin S gene. They are a car...

# Sickle Cell Disease Sickle cell disease occurs almost exclusively in African Americans in the United States. It is carried by 8-10% of the population. ## Sickle Cell Variants * **Sickle Cell Trait (HbAS):** The individual has one defective S gene and one normal hemoglobin S gene. They are a carrier but usually asymptomatic. However, under stressful circumstances such as high altitude, scuba diving, dehydration, or excess exertion, some sickling and symptoms may occur. * **Sickle Cell Anemia (HbSS):** This homozygous type involves inheritance of two defective genes and active sickle cell disease with crises. * **Sickle Cell HbSC Disease:** The individual inherits the defective S gene and also an abnormal hemoglobin C gene, resulting in a mild form of sickle cell disease. * **Sickle Cell HbSE Disease:** The individual inherits the defective S gene and an abnormal hemoglobin E gene, resulting in a moderate to mild form of sickle cell disease. * **HbS-beta Thalassemia:** The individual inherits both the defective S gene and the thalassemia gene, either type 0 (zero) or + (plus), resulting in moderate disease. Those with HbS 0 generally have a more severe form of disease than those with HbS +. ## Sickle Cell Crises * **Sequestrating:** Blood pools in an encapsulated organ, usually the spleen and/or liver (rare), resulting in decreased blood volume, shock, and sometimes rupture of the organ. Pain is severe, and hemoglobin levels fall. Splenic sequestration usually occurs between 9 months and 4 years and lasts 3-4 days. Treatment includes supportive care and sometimes transfusion. * **Vasoocclusive:** Sickled cells clump and occlude capillaries, interfering with blood flow to organs and causing ischemia and severe pain. Stroke or organ damage may occur. The most common site of occlusion is bone. Duration is 4 to 14 days. Treatment includes hydration and analgesia. * **Aplastic:** Infection (especially parvovirus) or folic acid deficiency cause decreased production of RBCs (hemoglobin to 3.9 g/dL with 0 reticulocytes) with pallor, tachycardia, anorexia, fever, and dyspnea. Duration is 5 to 10 days. Treatment includes supportive care and sometimes transfusion. * **Hemolytic:** Sudden onset of increased destruction of RBCs precedes bone marrow compensation, resulting in precipitous life-threatening decrease in hemoglobin and hematocrit. Duration varies. Treatment may include transfusions. ## Treatment for Sickle Cell Disease * **Prophylactic penicillin for children from 2 months to 5 years to prevent pneumonia.** * **Intravenous fluids to prevent dehydration.** * **Analgesics (morphine) during painful crises.** * **Folic acid for anemia.** * **Oxygen for congestive heart failure or pulmonary disease.** * **Blood transfusions with chelation therapy to remove excess iron OR erythropheresis, in which red cells are removed and replaced with healthy cells, either autologous or from a donor.**