Red blood cells containing mainly normal hemoglobin are round and flexible. But when oxygen is released by the red blood cells in people with sickle cell disease, the abnormal hemoglobin forces the cells to become distorted and rigid, often looking like the C-shaped farm tool called a sickle. Sickle cells tend to become trapped and to be destroyed in the liver and in the spleen. This results in a shortage of red blood cells, or anemia which, when severe, can cause an affected person to be pale, short of breath and easily tired. Certain conditions, such as enlargement of the spleen and infections, may worsen the anemia by speeding up destruction of red blood cells.
Infections also can reduce red blood cell production.
There are several forms of sickle cell disease. The effects of sickle cell disease vary greatly from one person to the next. Some affected people rarely are ill while others are frequently hospitalized. Infections are the leading cause of death in children with sickle cell disease. However, early diagnosis and treatment dramatically reduce the risk of infections and death.