sickle cell anemia

Sickle cell anemia:

Sickle cell anemia is an inherited blood disorder, characterized primarily by chronic anemia and periodic episodes of pain

The cause of sickle cell anemia is a genetic disorder in which the hemoglobin is defective. When the hemoglobin molecules gives up their oxygen, some will cluster together. This forms long, rod-like structures which cause the red blood cells to stiffen and assume a sickle shape. With the deformity, the cells cannot squeeze through the blood vessels, depriving organs and tissues of oxygen

Normal blood cells live for about one hundred twenty day in the blood, while the defective sickled cells live only ten to twenty. Because of their shortened lifespan, the blood is constantly deficient in red blood cells, a condition known as anemia

Sickle cell anemia is a genetic disorder that resulted from a mutation which occurred thousands of years ago in Africa, the Mediterranean basin, the Middle East, and India. At the time, deadly malaria epidemics cause great numbers of deaths. Those who inherited the sickle cell gene had an advantage: unlike children with normal red blood cells, they could survive malaria, and grow old enough to have their own offsprings, thus passing along the mutation. As the population migrated, so did the mutation. In countries where malaria is not a problem, like the United States, the sickle cell mutation is disorder, no longer providing a survival trait of value. Instead it is a serious threat. If a child inherits two of the recessive sickle cells genes, they will be born with sickle cell anemia

In the United States alone, sickle cell anemia affects approximately seventy-two thousand people, most of whose ancestors descended from Africa. About two million Americans carry the gene for sickle cell anemia

The clinical course of sickle cell anemia does not follow a single pattern; some patients have mild symptoms, and some have very severe symptoms:

Hand-foot syndrome. When the small blood vessels in the hands or feet are blocked, pain and swelling can result, along with fever. This may be the first symptom of sickle cell anemia in infants
Fatigue, paleness, and shortness of breath--all symptoms of anemia, or a shortage of red blood cells
Pain that occurs unpredictably in any body organ or joint, wherever the sickled blood cells block oxygen flow to the tissues. The frequency and amount of pain varies. Some patients have painful episodes (also called crises) less than once a year, and some have as many as fifteen or even more episodes in a year. The pain can last for a few hours, or for weeks. For especially severe, prolonged pain, the patient may have to be hospitalized and treated with painkillers and intravenous fluids. Pain is the principal symptom of sickle cell anemia in both children and adults
Eye problems are a common occurrence in people who suffer from sickle cell anemia. The retina does not receive the proper blood circulation, causing it to deteriorate, sometimes to the point of blindness
Yellowing of the skin and eyes indicates jaundice, resulting from the rapid breakdown of red blood cells The shortage of red blood cells can often result in a delayed growth in children, and/or a slight build as an adult
Both children and adults with sickle cell anemia are more vulnerable to infections than most. The cause is the damage to the spleen from the sickled cells, which prevents the organ from destroying bacteria in the blood. Infants or very young children can die in as little as nine hours from the onset of a fever. Pneumococcal infections were once the principle cause of death in the young, anemic children, until doctors began to routinely give them penicillin for prevention of the fever. The children are given penicillin twice a day from two moths until age five years. Sadly, several new strains of pneumonia have appeared that are resistant to the penicillin The defective hemoglobin damages the walls of the red blood cells, causing them to stick to the inner membranes of blood vessels. The result is a narrowed or blocked passage, which can lead to a stroke Acute chest syndrome is a life-threatening complication of sickle cell anemia, caused by an infection or trapped sickled cells in the lungs. It is characterized by chest pain, fever, and an abnormal chest x-ray

Hemoglobin electrophoresis is the most widely used diagnostic test. If the test is positive for the presence of sickle hemoglobin, a second test is performed

As yet, there is no cure for sickle cell anemia, but there are treatments available. Most rely heavily on painkilling drugs, both oral and intravenous. Blood transfusions are used to treat and prevent some of the sickle cell complications. The infusions of the correct anemia increase the normal red blood cell count, and treat spleen enlargement. Regular transfusions can prevent recurring strokes in children

The first effective drug treatment for adults was reported in 1995: the anticancer drug hydroxyurea. The drug reduced the painful crises and acute chest syndrome. Those on the drug also required fewer blood transfusions. The long term effects on both adults and children are still being studied

Patients with severe chest or back pain that prevents them from breathing well may be able to prevent complications through the use of an incentive spirometer. This is a small, plastic device, shaped like a tube, with a ball inside. The patient must breath into it hard enough to force the ball up, so helping them to breath more deeply

Most symptoms and complications of sickle cell amenia are treated as they occur. Laser coagulation and other eye surgeries may be used to prevent further vision loss in patients with eye problems. The knife may be recommended for certain kinds of organ damage- such as gallstoned or replacement of a hip. Leg ulcers are treated with cleaning solutions and zinc oxide, or skin grafts if the condition persists

With good health care, a sickle cell anemia sufferer can a productive life. In the past thirty years, the patients life expectancy has risen to the mid-forties

Some researchers are focusing on drugs that will increase the level of fetal hemoglobin in the blood. This is the form of hemoglobin that all humans produce before birth, but stop making shortly after birth. By the age of half a year, most humans have little to none of the fetal form left in the bloodstream. Some of those with sickle cell anemia, however, continue producing the hemoglobin. These patients have less severe forms of the disorder. The fetal hemoglobin seems to prevent sickling, and has a longer lifespan in the blood. Hydroxyurea appears to work primarily by simulating to manufacturing of fetal hemoglobin. There is evidence that administering hydroxyurea with erythropoietin, a genetically engineered hormone that stimulates red blood cell production, may work better than hydroxyurea alone. This combination offers a lower dose to achieve the needed level of the hemoglobin production. However, both drugs have serious side effects, so scientists continue to look for safer agents. Butyrate is a rather simple fatty acid, widely used as food additive, and is also being investigated. It may be an agent to simulate production of fetal hemoglobin

Clotrimazole, an over the counter fungal medication, is being looked at as a potential treatment. It seems to prevent the loss of water from the red blood cell which contributes to sickling

Bone marrow transplants have been shown as an effective cure for severely affected children. The procedure is risky, and only about eighteen percent of the afflicted children are likely to have a matched sibling

The ultimate cure for sickle cell anemia may be gene therapy. In sickle cell, the gene that switches on production of adult hemoglobin shortly before birth is faulted. Until now, researchers had difficulty finding an animal model that could be used as a test subject. Recently, however, a strain of mice has been engineered which show similar characteristics of sickle cell anemia to humans

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