Signs, Symptoms, and Complications
Sickle cell disease presentation is extremely variable. Some people may have mild symptoms, while others may experience severe symptoms and frequent complications. Infants with sickle cell disease are typically normal at birth, developing symptoms in their first year as hemoglobin F is replaced with hemoglobin S as the dominant hemoglobin produced. People with sickle cell disease due to homozygous Hb S (SS) are more likely to have severe symptoms than those with heterozygous Hb S (AS) or Hb C (SC). Those with sickle cell trait are generally healthy but may experience symptoms associated with sickle cell disease when they have lower levels of oxygen from intense exercise or dehydration, as with athletes, or from changes in altitude.
Symptoms and complications of sickle cell disease may include:
- Pain crises. Episodes of pain that can last for extended periods of time are the most common complication of sickle cell disease. The pain is associated with the narrowing or obstruction of small blood vessels (called vaso-occlusion), which reduces or prevents blood flow to the affected area and can cause tissue damage. The location of the pain and its duration can vary from crisis to crisis and can occur throughout the body, especially in the bones, joints, lungs, and belly. Pain and swelling in the hands and feet is often one of the first symptoms noticed in young children. Decreased oxygen, infection, dehydration, change in altitude, and temperature extremes can precipitate a pain crisis, but many occur without an identifiable trigger. Symptoms from a pain episode generally resolve within a few days to several weeks. Some people with sickle cell disease may experience crises once every few years, while others may have several episodes a year.
- Anemia is a common complication of the disease because of the shortened life of the sickled red blood cells (RBCs). Those affected may experience fatigue, decreased stamina, dizziness, paleness, shortness of breath, and an increased heart rate. Anemic children may grow and develop more slowly. An aplastic crisis may occur when there is a disruption in RBC production. The most common reason for an acute decrease in RBC production in those affected by sickle cell disease is an infection by parvovirus B19, which selectively affects RBC production in the bone marrow.
- Infections, especially lung infections, can be serious in those with sickle cell disease. According to the Centers for Disease Control and Prevention, pneumonia is a leading cause of death in children with sickle cell disease.
- Acute chest syndrome, due to vaso-occlusion, is a lung injury that can cause symptoms such as coughing, chest pain, and fever. This condition requires prompt medical attention. It can develop rapidly and become life-threatening.
- Stroke is one of the most feared complications of sickle cell anemia as it can cause permanent damage and disability. Stroke is more common in children than in adults, occurring in 10% of children with sickle cell anemia.
- Splenic sequestration is the rapid enlargement of the spleen when many sickle cells become trapped there. Occurring primarily in children, it can cause symptoms such as abdominal pain, nausea, and weakness that can progress to shock. This condition can be life-threatening and may require removal of the spleen.
Other complications of sickle cell disease may include gallstones, bone necrosis (tissue death), leg ulcers, disease of the retina in the eye (retinopathy), caloric and nutritional deficiencies (folic acid, zinc), and sustained erection (priapism). Although present in young patients, people with sickle cell disease who are older than 40 more commonly experience symptoms of kidney disease, with 60% developing proteinuria and a small number developing renal failure.
Found throughout the world, sickle cell anemia is most common in those of African descent and in those from Mediterranean countries, the Middle East, India, the Caribbean, and Central or South America. According to the National Heart, Lung, and Blood Institute, about 70,000 to 100,000 people in the U.S. have sickle cell anemia. It affects about one in 500 African Americans and one in 36,000 Hispanic Americans. As many as two million people in the U.S., including one in 12 African Americans, are estimated to have sickle cell trait.