In the United States, sickle cell anemia occurs mostly among African Americans. About 1 in 12 African Americans are carriers of the abnormal trait. Carriers usually have no symptoms. However, if two carriers have children, there is a 1 in 4 chance that a child will have the disease. Infections, stress, loss of body water, or low blood oxygen can provoke a sickle cell crisis.
Crisis usually entails severe pain in the abdomen, chest, muscles, or bones.
There may be jaundice, dark urine, or a low fever. There is an increased risk of a blood infection. The crisis can last from a day or two to several weeks. In another type of crisis, production of new red blood cells drops sharply. This leads to sleepiness, difficulty breathing, and possible coma.