What Is Sickle Cell Anemia?
Sickle cell disease is an inherited blood disorder that affects red blood cells. People with sickle cell disease have red blood cells that contain mostly hemoglobin* S. Sometimes these red blood cells become sickle-shaped (crescent shaped) and have difficulty passing through small blood vessels. When sickle-shaped cells block small blood vessels, less blood can reach that part of the body. Tissue that does not receive a normal blood flow eventually becomes damaged. This is what causes the complications of sickle cell disease. There is currently no universal cure for sickle cell disease.
What Cause Sickle Cell Anemia Disease?
Hemoglobin – is the main substance of the red blood cell. It helps red blood cells carry oxygen from the air in our lungs to all parts of the body. Normal red blood cells contain hemoglobin A. Hemoglobin S and hemoglobin C are abnormal types of hemoglobin.
How Is Sickle Cell Anemia Inherited?
Sickle cell conditions are inherited from parents in much the same way as blood type, hair color and texture, eye color and other physical traits. The types of hemoglobin a person makes in the red blood cells depend upon what hemoglobin genes the person inherits from his or her parents. Like most genes, hemoglobin genes are inherited in two sets…one from each parent.
Examples:
If one parent has Sickle Cell Anemia and the other is Normal, all of the children will have sickle cell trait.If one parent has Sickle Cell Anemia and the other has Sickle Cell Trait, there is a 50% chance (or 1 out of 2) of having a baby with either sickle cell disease or sickle cell trait with each pregnancy.
When both parents have Sickle Cell Trait, they have a 25% chance (1 of 4) of having a baby with sickle cell disease with each pregnancy.
Example of an Inheritance Pattern for Sickle Cell Trait
The image shows how sickle cell genes are inherited. A person inherits two copies of the hemoglobin gene—one from each parent. A normal gene will make normal hemoglobin (A). An abnormal (sickle cell) gene will make abnormal hemoglobin (S).
When both parents have a normal gene and an abnormal gene, each child has a 25 percent chance of inheriting two normal genes; a 50 percent chance of inheriting one normal gene and one abnormal gene; and a 25 percent chance of inheriting two abnormal genes.
What Is The Trait?
If you inherit one copy of the sickle cell gene (from one parent), you won't have sickle cell anemia. Instead, you'll have sickle cell trait.
People who have sickle cell trait usually have no symptoms and lead normal lives. However, some people may have medical complications.
People who have sickle cell trait also can pass the sickle cell gene to their children.
If Sickle Cell Anemia Is Not An Illness Why Are People Tested?
Babies are tested to see if they have sickle cell disease. Teens and adults are tested mainly to see if they can have a baby with the disease.
What Medical Problems Are Caused By Sickle Cell Anemia?
The effects of sickle cell disease vary greatly from one person to the next. Some affected individuals are generally healthy, while others are frequently hospitalized. Common problems seen in sickle cell disease include the following:
What Are the Signs and Symptoms of Sickle Cell Anemia?
The signs and symptoms of sickle cell anemia vary. Some people have mild symptoms. Others have very severe symptoms and often are hospitalized for treatment.
Sickle cell anemia is present at birth, but 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 the disease's complications.
How Many People Have Sickle Cell Disease?
Sickle cell disease is a global health problem. In the United States it is estimated that over 70,000 people and 200,000 in the US population have sickle cell disease. About 1,000 babies are born with the disease each year in America.
How Long Does a Person With Sickle Cell Disease Live?
Babies are tested to see if they have sickle cell disease. Teens and adults are tested mainly to see if they can have a baby with the disease.
What Medical Problems Are Caused By Sickle Cell Anemia?
The effects of sickle cell disease vary greatly from one person to the next. Some affected individuals are generally healthy, while others are frequently hospitalized. Common problems seen in sickle cell disease include the following:
- Anemia: Individuals with sickle cell disease have a decreased number of red blood cells. As a result, they may be pale, tire easily and have shortness of breath.
- Infections: Infants and young children with sickle cell disease have an increased risk of contracting serious bacterial infections, such as pneumonia and meningitis (infection of the lining of the brain). Infections are a major cause of death in children with sickle cell disease.
But deaths have declined dramatically since providers began routinely treating children with sickle cell disease with the antibiotic penicillin to help prevent infections. Affected children should receive penicillin twice daily between the ages of 2 months and 5 years of age (1, 2).
All states now screen newborns for sickle cell disease as part of a panel of newborn screening tests (2). Early identification of affected babies alerts health care providers to begin treatment before dangerous infections occur.
It is important for babies and children with sickle cell disease to be given regular childhood vaccinations. These vaccines are recommended for all babies starting at 2 months of age. Children with sickle cell disease should be given additional vaccinations, including (2, 3):
- Flu (influenza) shot: This should be given every year, beginning at 6 months of age.
- Pneumococcal vaccine (23-valent pneumococcal vaccine): This protects against additional types of bacteria. It is given at 2 and 5 years of age.
- Meningococcal vaccine: This vaccine, which protects against meningitis, is given after age 2.
- Pain episodes: These are the most common symptom of sickle cell disease. Some affected individuals have one or fewer pain episodes a year, while others may have 15 or more. Pain episodes usually last a few hours to a few days, but they may sometimes last for weeks. Pain can occur in any organ or joint in the body, wherever sickle-shaped cells pile up and block blood vessels.
Mild pain episodes can be treated at home with over-the-counter pain medications (such as acetaminophen and ibuprofen) and heating pads. But some pain episodes may be severe and need to be treated in the hospital with strong pain-killing drugs.
The following steps may help prevent pain episodes in some affected individuals (2, 4):- Drink plenty of fluids.
- Avoid getting too hot or too cold.
- Avoid places with high altitudes where oxygen levels are low.
- Avoid extreme exercise.
- Limit emotional stress.
- Stroke: A stroke can occur when sickle-shaped cells block a blood vessel in the brain. About 10 percent of children with sickle cell disease have a stroke (2, 4). Stroke can lead to lasting disabilities, including learning problems.
Providers can sometimes identify children who are at increased risk for stroke using a special type of ultrasound examination. In some cases, a provider may recommend regular blood transfusions to help prevent a stroke.
- Splenic crisis: The spleen is an organ that removes worn- out red blood cells and helps fight infection. In sickle cell disease, the spleen may become dangerously enlarged because it is clogged up with abnormal red blood cells. Symptoms include pain on the left side of the abdomen, weakness and rapid heart rate. This condition is treated in the hospital with blood transfusions. If the condition recurs frequently, the provider may recommend regular blood transfusions or removal of the spleen.
- Vision problems: When tiny blood vessels in the eye become blocked with sickle-shaped cells, vision problems and even blindness can result. Some individuals with sickle cell disease may need regular eye exams. When eye problems occur, laser treatment often prevents further vision loss.
- Slow growth: Children with sickle cell disease tend to grow slower than normal and enter puberty later than other children due to anemia.
What Are the Signs and Symptoms of Sickle Cell Anemia?
The signs and symptoms of sickle cell anemia vary. Some people have mild symptoms. Others have very severe symptoms and often are hospitalized for treatment.
Sickle cell anemia is present at birth, but 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 the disease's complications.
How Many People Have Sickle Cell Disease?
How Long Does a Person With Sickle Cell Disease Live?
The average life expectancy in America has improved. It is now in the mid 40 years of age range.
Can People With Sickle Cell Disease Live a Productive Life?
Yes. But like all patients with chronic disease, sickle cell patients are best managed in a comprehensive multi-disciplinary program of care and a strong extended support system.
No. It is also present in Portuguese, Spanish, French Corsicans, Sardinians, Sicilians, mainland Italians, Greeks, Turks and Cypriots. Sickle cell disease also appears in Middle Eastern countries and Asia.
How Is Sickle Cell Anemia Treated?
Although there is no cure for sickle cell anemia. Basic treatment of painful crises relies heavily on pain-killing drugs and oral and intravenous fluids to reduce pain and prevent complications.
Blood transfusions are used to treat and to prevent some of the complications of sickle cell anemia. Transfusions correct anemia by increasing the number of normal red blood cells in circulation. Transfusions are used to treat spleen enlargement in children before the condition becomes life-threatening. Regular transfusion therapy also can help prevent recurring strokes in children at high risk of crippling nervous system complications.
Giving young children with sickle cell anemia oral penicillin twice a day, beginning when the child is about 2 months old and continuing until the child is at least 5 years old, can prevent pneumococcal infection and early death in these children.
The abnormal hemoglobin molecules tend to cluster together and form long, rod-like structures. These structures cause some red blood cells to become stiff and to assume a sickle shape.
Sickle cell anemia patients with severe chest or back pain that prevents them from breathing deeply may be able to avoid potentially serious lung complications associated with acute chest syndrome by using an incentive spirometer. This is a small plastic device, shaped like a tube, with a ball inside. The patient must breathe into it hard enough to force the ball up the tube, so using it helps the patient breathe more deeply.
Most complications of sickle cell anemia are treated as they occur. Surgery may be recommended for certain kinds of organ damage.
Proper nutrition, good hygiene, bed rest, protection against infections, and avoidance of other stresses all are important in maintaining good health and preventing complications. Regular visits to a physician or clinic that provides comprehensive care are necessary to identify early changes in the patient's health and ensure that the person receives immediate treatment.Today, with good health care, many people with sickle cell anemia are in reasonably good health much of the time and living productive lives. In fact, in the past 30 years, the life expectancy of people with sickle cell anemia has increased.
Is There a Cure For Sickle Cell Anemia?
Bone marrow transplant offers the only potential cure for sickle cell anemia. But, finding a donor is difficult and the procedure has serious risks associated with it, including death.
What Is The Future Of Sickle Cell Anemia Treatment?
Some researchers are focusing on identifying drugs that will increase the level of fetal hemoglobin in the blood. Fetal hemoglobin is a form of hemoglobin that all humans produce before birth, but most stop making shortly after birth.
Most humans have little fetal hemoglobin left in their bloodstream by the time they reach the age of 6 months. However, some people with sickle cell anemia continue to produce large amounts of fetal hemoglobin after birth, and studies have shown that these people have less severe cases of the disease. Fetal hemoglobin seems to prevent sickling of red cells, and cells containing fetal hemoglobin tend to survive longer in the bloodstream.
Hydroxyurea appears to work primarily by stimulating production of fetal hemoglobin. There is some evidence that administering hydroxyurea with erythropoietin, a genetically engineered hormone that stimulates red cell production, may make hydroxyurea work better. This combination approach offers the possibility that lower doses of hydroxyurea can be used to achieve the needed level of fetal hemoglobin.
Butyrate, a simple fatty acid that is widely used as a food additive, is also being investigated as an agent that may increase fetal hemoglobin production.
The ultimate cure for sickle cell anemia may be gene therapy. In sickle cell anemia, the gene which switches on production of adult hemoglobin shortly before birth, is defective. Two approaches to gene therapy are being explored. Some scientists are looking into whether correcting this gene and inserting it into the bone marrow of people with sickle cell anemia will result in the production of normal adult hemoglobin. Others are looking at the possibility of turning off the defective gene and simultaneously reactivating another gene that turns on production of fetal hemoglobin. In both cases, the research is at a very early stage. Progress is being made. This is an important advance in the search for an effective treatment and eventual cure for sickle cell disease.How Is Sickle Cell Anemia Detected?
Early diagnosis of sickle cell anemia is critical so that children who have the disease can receive proper treatment.
More than 40 states now perform a simple, inexpensive blood test for sickle cell disease on all newborn infants. This test is performed at the same time and from the same blood samples as other routine newborn screening tests. Hemoglobin electrophoresis is the most widely used diagnostic test.If the test shows the presence of sickle hemoglobin, a second blood test is performed to confirm the diagnosis. These tests also tell whether the child carries the sickle cell trait.
How Can a Patient With Sickle Cell Anemia As Well As Their Family And Friends Be Helped With Coping?
Sickle cell patients and their families may need help in handling the economic and psychological stresses of coping with this serious chronic disease.
Sickle cell centers and clinics can provide information and counseling on handling these problems. Parents should try to learn as much about the disease as possible so that they can recognize early signs of complications and seek early treatment.
It Is Posible To Detect That Disease In An Unborn Baby?
Yes. By sampling the amniotic fluid or tissue taken from the placenta, doctors can tell whether a fetus has sickle cell anemia or sickle cell trait. This test can be done as early as the first trimester of pregnancy.
Chorionic Villus Sampling is also another prenatal test. Chorionic villus sampling or CVS is a test done during early pregnancy that can find certain genetic problems with the fetus. The test is commonly done when either you or the baby biology father has a disease that runs in the family. The test can be done as early as 10 to 12 weeks.
What Should Future Parents Know?
People who are planning to become parents should know whether they are carriers of the sickle cell gene, and, if they are, they may want to seek genetic counseling. The counselor can tell prospective parents what the chances are that their child will have sickle cell trait or sickle cell anemia. Accurate diagnostic tests and information are available from health departments, neighborhood health centers, medical centers and clinics that care for Individuals with sickle cell anemia.
Bibliography:
Bibliography:
- American Sickle Cell Anemia Association. (s.f.). Recuperado el 23 de Enero de 2011, de http://www.ascaa.org/default.asp
- Foundation for Better Health Care. (s.f.). Recuperado el 23 de Enero de 2011, de http://www.fbhc.org/Patients/Modules/sicklecell.cfm
- March of Dimes. (Febrero de 2008). Recuperado el 23 de Enero de 2011, de http://www.marchofdimes.com/baby/birthdefects_sicklecell.html
- Mayo Foundation for Medical Education and Research. (1 de Abril de 2009). Recuperado el 23 de Enero de 2011, de http://www.mayoclinic.com/health/sickle-cell-anemia/DS00324/DSECTION=treatments-and-drugs
- National Heart, Lung and Blood Institute. (s.f.). Recuperado el 23 de Enero de 2011, de http://www.nhlbi.nih.gov/health/dci/Diseases/Sca/SCA_Causes.html
- Sickle Cell Disease Association of America. (2005). Recuperado el 23 de Enero de 2011, de http://www.sicklecelldisease.org/about_scd/index.phtml
- Wisconsin state Laboratory og Hygiene. (s.f.). Recuperado el 23 de Enero de 2011, de http://www.slh.wisc.edu/newborn/brochures/b2print.pdf
