3. Normal and Sickled Red Blood Cells in Blood Vessels Figure A shows normal red blood cells flowing freely in a blood vessel. The inset image shows a cross-section of a normal red blood cell with normal hemoglobin. Figure B shows abnormal, sickled red blood cells clumping and blocking the blood flow in a blood vessel. The inset image shows a cross-section of a sickled red blood cell with abnormal strands of hemoglobin. Source from http://www.nhlbi.nih.gov/health/dci/Diseases/Sca/SCA_WhatIs.html
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10. Who Is At Risk? The disease originated in at least 4 places in Africa, Mediterranean countries (such as Turkey, Greece, and Italy), and in the Indian/Saudi Arabian subcontinent. It exists in all countries of Africa and in areas where Africans have migrated. It is most common in West and Central Africa where as many as 25% of the people have sickle cell trait and 1-2% of all babies are born with a form of the disease. In the United States with an estimated population of over 270 million, about 1,000 babies are born with sickle cell disease each year. In contrast, Nigeria, with an estimated 1997 population of 90 million, 45,000-90,000 babies with sickle cell disease are born each year.
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Editor's Notes
Sickle cell anemia is an inherited, lifelong condition. People who have sickle cell anemia are born with it. They inherit two copies of the sickle cell gene, one from each parent. People who inherit a sickle cell gene from one parent and a normal gene from the other parent have a condition called sickle cell trait. Sickle cell trait is different from sickle cell anemia. People with sickle cell trait don’t have the condition, but they have one of the genes that cause the condition. Like people with sickle cell anemia, people with sickle cell trait can pass the gene on when they have children. To learn more about sickle cell trait, see the section on causes of sickle cell anemia .
Anemia Anemia (uh-NEE-me-uh) is a condition in which a person’s blood has a lower than normal number of red blood cells, or the red blood cells don’t have enough hemoglobin (HEE-muh-glow-bin). Hemoglobin is an iron-rich protein that gives blood its red color and carries oxygen from the lungs to the rest of the body. Red blood cells are made in the spongy marrow inside the large bones of the body. Bone marrow constantly makes new red blood cells to replace old ones. Normal red blood cells last about 120 days in the bloodstream and then die. Their main role is to carry oxygen, but they also remove carbon dioxide (a waste product) from cells and carry it to the lungs to be exhaled. In sickle cell anemia, a lower-than-normal number of red blood cells occurs because sickle cells don’t last very long. Sickle cells die faster than normal red blood cells, usually after only about 10 to 20 days. The bone marrow can’t make new red blood cells fast enough to replace the dying ones. The result is anemia. Outlook Sickle cell anemia affects millions of people worldwide. There are excellent treatments for the symptoms and complications of the condition, but in most cases there’s no cure. (Some researchers believe that bone marrow transplants may offer a cure in a small number of cases.) Over the past 30 years, doctors have learned a great deal about the condition. They know what causes it, how it affects the body, and how to treat many of the complications. Today, with good health care, many people with the condition live close to normal lives and are in fairly good health much of the time. These people can live into their forties or fifties, or longer.
Sickle cell anemia affects millions of people worldwide. It’s most common in people whose families come from Africa, South or Central America (especially Panama), Caribbean islands, Mediterranean countries (such as Turkey, Greece, and Italy), India, and Saudi Arabia. In the United States, sickle cell anemia affects about 70,000 people. Mainly affects African Americans, with the condition occurring in about 1 in every 500 African American births. Hispanic Americans also are affected; the condition occurs in 1 out of every 1,000 to 1,400 Hispanic American births. About 2 million Americans have sickle cell trait. About 1 in 12 African Americans has sickle cell trait.
Sickle cell anemia affects millions of people worldwide. It’s most common in people whose families come from Africa, South or Central America (especially Panama), Caribbean islands, Mediterranean countries (such as Turkey, Greece, and Italy), India, and Saudi Arabia. In the United States, sickle cell anemia affects about 70,000 people. Mainly affects African Americans, with the condition occurring in about 1 in every 500 African American births. Hispanic Americans also are affected; the condition occurs in 1 out of every 1,000 to 1,400 Hispanic American births. About 2 million Americans have sickle cell trait. About 1 in 12 African Americans has sickle cell trait.
What Are the Signs and Symptoms of Sickle Cell Anemia? The signs and symptoms of sickle cell anemia are different in each person. Some people have mild symptoms. Others have very severe symptoms and are often hospitalized for treatment. Although sickle cell anemia is present at birth, many infants don’t show any signs until after 4 months of age. The most common signs and symptoms are linked to anemia and pain. Other signs and symptoms are linked to some of the complications of the condition. Anemia The general signs and symptoms of anemia are fatigue (tiredness), pale skin and nail beds, jaundice (yellowing of the skin and eyes), and shortness of breath. Pain (Sickle Cell Crisis) Sudden episodes of pain throughout the body are a common symptom of sickle cell anemia and are often referred to as “sickle cell crises.” A sickle cell crisis occurs when the red blood cells sickle (become “C” shaped) and stick together in clumps. The clumps block the flow of blood through the small blood vessels (capillaries) in the limbs and organs. Sickle crises can cause acute or chronic pain. Acute pain is the most common type. This is sudden pain that can range from mild to very severe. The pain usually lasts from hours to a few days. Chronic pain usually lasts for weeks to months. Chronic pain can be hard to bear and mentally draining. This pain may severely limit daily activities. Almost all people with sickle cell anemia have painful crises at some point in their lives. Some have a crisis less than once a year. Others may have 15 or more crises in a year. Many factors can contribute to a sickle cell crisis. Often, more than one factor is involved and the exact cause can’t be identified. Factors that occur in your body and aren’t under your control can cause a sickle cell crisis, such as an infection. Factors that you can control also can affect whether you have a sickle cell crisis. For example, dehydration (when your body doesn’t have enough fluid) can increase your chances of having a sickle cell crisis. Drinking plenty of fluids so your body is hydrated can often help decrease the chance of a crisis. The most common sites affected by sickle cell crises are the bones, lungs, abdomen, and joints. The blocked blood flow can cause pain and organ damage.
Complications of Sickle Cell Anemia Complications of sickle cell anemia come from the effects of sickle cell crises on different parts of the body. Hand-Foot Syndrome When sickle cells block the small blood vessels in the hands or feet, pain and swelling along with fever can occur. One or both hands and/or feet may be affected at the same time. Pain may be felt in the many bones of the hands and feet. Swelling usually occurs on the back of the hands and feet and moves into the fingers and toes. This may be the first sign of sickle cell anemia in infants. Splenic (Sequestration) Crisis The spleen is an organ in the abdomen that filters out abnormal red blood cells and helps fight infection. Sometimes, the spleen traps many cells that should be in the bloodstream and it grows large. This causes anemia. Blood transfusions may be needed until the body can make more cells and recover. If the spleen becomes too clogged with sickle cells, it can’t work normally. It begins to shrink and stop working. Infections Both children and adults with sickle cell anemia have a hard time fighting infections. Sickle cell anemia can damage the spleen. Infants and young children with a damaged spleen are more likely to get infections that can kill them within hours or days. Pneumonia is the most common cause of death in young children who have sickle cell anemia. Meningitis, influenza, and hepatitis are other infections that are common in people with sickle cell anemia. Acute Chest Syndrome Acute chest syndrome is a life-threatening condition linked to sickle cell anemia. It's similar to pneumonia and is caused by an infection or by sickle cells trapped in the lungs. People with this condition usually have chest pain, fever, and an abnormal chest x ray. Over time, lung damage may lead to pulmonary arterial hypertension (see below). Delayed Growth and Puberty in Children Children with sickle cell anemia often grow more slowly and reach puberty later than other children. A shortage of red blood cells (anemia) causes the slow growth rate. Adults with sickle cell anemia often are slender or small in size. Stroke Sickle-shaped red blood cells may stick to the walls of the tiny blood vessels in the brain. This can cause a stroke. This type of stroke occurs mainly in children. The stroke can cause learning disabilities or more severe problems. Eye Problems The retina, a thin layer of tissue at the back of the eye, takes the images you see and sends them to your brain. When the retina doesn’t get enough blood, it can weaken. A weak retina can cause serious problems, including blindness. Priapism Males with sickle cell anemia may have painful and unwanted erections called priapism (PRI-a-pizm). This happens because the sickle cells stop blood flow out of an erect penis. Over time, priapism can damage the penis and lead to impotence. Gallstones When red blood cells die, they release their hemoglobin, which the body breaks down into a compound called bilirubin. When there is too much bilirubin in the body, stones can form in the gallbladder. Gallstones can cause steady pain that lasts for 30 minutes or more in the upper right side of the belly, under the right shoulder, or between the shoulder blades. The pain may happen after eating fatty meals. People with gallstones may have nausea, vomiting, fever, sweating, chills, clay-colored stool, or jaundice (yellowish color of the skin or whites of the eyes). Ulcers on the Legs Sickle cell ulcers (sores) usually begin as small, raised, crusted sores on the lower third of the leg. Leg sores occur more often in males than in females and usually appear between the ages of 10 and 50. The cause of leg ulcers is not clear. The number of ulcers can vary from one to many. Some heal rapidly, but others persist for years or come back after healing. Pulmonary Arterial Hypertension (High Blood Pressure) Damage to the small blood vessels in the lungs makes it hard for the heart to pump blood through the lungs. This causes blood pressure in the lungs to increase. This condition is called pulmonary arterial hypertension. Excessive shortness of breath is an important symptom linked to this problem. Multiple Organ Failure Multiple organ failure is rare, but serious. It happens when a person has a sickle cell crisis that causes two out of three major organs (lungs, liver, or kidney) to fail. Symptoms linked to this complication are a fever and changes in mental status such as sudden tiredness and loss of interest in your surroundings.
How Is Sickle Cell Anemia Diagnosed? Early diagnosis of sickle cell anemia is very important so that children who have the condition can get proper treatment. In the United States, 44 States, the District of Columbia, Puerto Rico, and the U.S. Virgin Islands now test all newborns for sickle cell anemia. In the other six States, you can request a sickle cell test. The test uses blood from the same blood samples used for other routine newborn screening tests. It can show whether the newborn infant has sickle cell anemia or sickle cell trait. If the first test shows some sickle hemoglobin, a second blood test is done to confirm the diagnosis. The second blood test looks at how hemoglobin moves in an electric field, a process called electrophoresis (ee-LEK-tro-for-EE-sis). Sickle hemoglobin moves differently than normal hemoglobin. Electrophoresis is usually used to diagnose older children and adults. It’s also possible to identify sickle cell anemia before birth. This is done using a sample of amniotic fluid or tissue taken from the placenta. (Amniotic fluid is the fluid in the sac surrounding a growing embryo. The placenta is the organ that attaches the umbilical cord to the mother’s womb.) This test can be done as early as the first few months of pregnancy. It identifies the sickle gene, rather than the hemoglobin it makes.
Treating Pain Mild painful crises can be managed with treatments such as over-the-counter medicine and heating pads. However, severe pain may need to be treated in a hospital. Painful crises are the leading cause of emergency room visits and hospitalizations of people with sickle cell anemia. The usual treatments for acute (short-term) pain crises are pain-killing medicines and fluids, given either by mouth or through a vein, to prevent dehydration (a condition in which your body doesn’t have enough fluids). The pain-killing medicines most often used are acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs), and narcotics such as meperidine, morphine, oxycodone, and others. The treatment of patients who have mild-to-moderate pain usually begins with NSAIDs or acetaminophen. If pain continues, a narcotic may be added. Moderate-to-severe pain is often treated with narcotics. The narcotic may be used alone or together with NSAIDs or acetaminophen. Narcotic abuse and addiction are pain management issues that must be considered in any pain control plan. A medicine called hydroxyurea may be given to adults and older adolescents with severe sickle cell anemia to reduce their number of painful crises. This medicine is used only to prevent these crises, not to treat them when they occur. Given daily, hydroxyurea can reduce the frequency of painful crises and of acute chest syndrome. People taking the medicine also may need fewer blood transfusions. People taking hydroxyurea must be watched carefully because the medicine can cause serious side effects, including an increased risk of dangerous infections. Some evidence suggests that long-term use of hydroxyurea can cause tumors or leukemia. Because of these risks, the medicine is usually only used in adults and older teenagers with severe sickle cell anemia. Although hydroxyurea is being tested in infants and children at this time, it won’t be approved for use in children until its long-term effects can be more closely studied.
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