Symptoms
Sickle cell anemia can cause many symptoms and life-threatening complications, including blocked blood vessels, worsening anemia, and serious infections Table 01. Patients with sickle cell anemia often have episodes of pain. Sickle-shaped cells stick to the walls of small blood vessels and have difficulty passing through them. The misshapen cells can clog the blood vessels, keeping needed oxygen from reaching the surrounding tissues. The blockages and resulting lack of blood supply can damage vital organs, such as the lungs, bones, liver, and kidneys. Clogging of the small vessels in the eye can deprive the part of the eye that receives and processes light (the retina) of needed nutrients, and can lead to blindness. In men, the penis may become painfully erect, a condition called priapism. Leg ulcers may occur when small vessels become blocked. Patients with sickle cell anemia are prone to gallbladder disease, and may develop bone complications when bone cells don't receive needed oxygen and nourishment. Children with sickle cell anemia are prone to strokes, which can cause permanent disabilities. Strokes occur when the sickled cells block or narrow the diameter of blood vessels that supply the brain with oxygen. Hand/foot syndrome occurs when small blood vessels in the hands or feet become blocked, resulting in pain, swelling, and sometimes fever.
Table 1. Symtoms and Complications of Sickle Cell Anemia
Symptoms in adults and children Anemia Fatigue Frequent infections Painful joints and bones Acute chest or abdominal pain Slow growth Leg ulcers Stroke Symptoms in infants Fever Jaundice Swollen extremities and joints Pneumonia Patients with chronic anemia feel tired, their fingernail beds and mucous membranes become pale, and their skin may have a grayish tint.
Pain is a primary symptom of sickle cell anemia in adults and children. Pain occurs during a sickle cell crisis because blocked blood vessels keep necessary oxygen from tissue cells, in effect “starving” them. Ninety percent of patients receiving hospital care for sickle cell disease experience severe pain in the bones, joints, or muscles. The pain may occur in the chest, back, abdomen, arms, or legs. Patients may have pain in one or more areas at once. Extremity pain usually occurs in both arms or both legs. Symptoms of a crisis can be mild or severe, and the pain may last for a few hours or for several weeks. Patients may have as few as 1 episode or as many as 15 or more episodes per year. Pain tends to occur in the same areas during subsequent crises.
Fainting, light-headedness, or increasing fatigue may be the first sign of an acute episode of suddenly worsening anemia (a sequestration crisis). A sequestration crisis is a serious type of sickle cell episode during which huge numbers of red blood cells collect in the spleen. Anemia worsens due to the decrease in circulating red blood cells. The spleen normally helps the immune system fight disease-causing infections. Since most adults with sickle cell anemia no longer have functioning spleens, sequestration crises are more common in children. Patients who have sickle cell anemia and damaged spleens often develop serious infections because their bodies cannot mount an adequate defense against bacteria, viruses, and other invaders. Infection is a leading cause of death in children with sickle cell anemia.
Patients may develop jaundice (characterized by a yellowing of the whites of the eyes) as a result of liver malfunction and rapid breakdown of red blood cells.
Fever, cough, rash, headache, neck stiffness, or difficulty breathing or urinating may indicate an infection.
Patients may experience depression or anxiety. Repeated painful, life-threatening, or incurable conditions often lead to feelings of hopelessness, helplessness, or anxiety. Frequent pain crises can be especially discouraging.
People with sickle cell trait (one abnormal gene) do not usually have symptoms, but may develop pain and other problems under certain circumstances. Stress, infections, or a lack of oxygen may trigger a painful episode in people with sickle cell trait. People with sickle cell trait may also develop blood in the urine, and may be prone to kidney infections.
Due to a lack of sufficient circulating red blood cells, adults with sickle cell anemia tend to be short, and children with sickle cell anemia may grow slowly and enter puberty later than their peers.
Risk Factors
Sickle cell anemia occurs predominantly in people of African descent, but also occurs in people from Mediterranean, Indian, and Middle Eastern descent. Thousands of years ago in this region of the world, a malaria epidemic killed many inhabitants. Some people survived the epidemic because they carried a single sickle cell mutation that made them immune to malaria. The survivors passed the defective gene to their children, and as people moved to other parts of the world, the genetic mutation spread.
In the US, African-Americans, Native Americans, and Hispanics from the Caribbean, Central America, and parts of South America are more likely than other Americans to have sickle cell anemia. One in 375 African-Americans, 1 in 3,000 Native Americans, 1 in 20,000 Hispanics, and 1 in 60,000 whites are born with sickle cell disease. Eight percent to twelve percent of African-Americans have sickle cell trait.
Various factors can trigger a painful sickle cell crisis. Sickle cell crises can be triggered by any event that decreases blood circulation or reduces the amount of oxygen in the blood. Low oxygen levels, cold temperatures, dehydration, infection, drinking large amounts of alcohol, stress, and pregnancy can lead to a crisis. Dehydration is especially common inpatients with sickle cell anemia because their kidneys are unable to properly conserve water.
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I'm Kristen Dore, PharmD. Welcome to PDR Health!

