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The
Department of Radiology and Nuclear Medicine
of the Uniformed Services University of the Health Sciences Bethesda, Maryland |
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Sickle Cell Anemia |
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The
Department of Radiology and Nuclear Medicine
of the Uniformed Services University of the Health Sciences Bethesda, Maryland |
|
Sickle Cell Anemia |
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Sickle Cell Anemia |
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| Introduction
Sickle Cell Anemia (SCA) is caused by a change in the chemical composition of the protein (hemoglobin or Hgb) that carries the oxygen inside of the red blood cells (RBC's). Normal Hgb is a round or ball-shaped folded molecule composed of 4 protein subunits - 2 alpha chains and 2 beta chains. The chemical change is a valine amino acid substituted for glutamic acid in both of the beta chains (HbSS). These chemical changes in hemoglobin cause the shape of the molecule to change under certain conditions such as lowered oxygen concentration and dehydration. Deoxygenated HgSS molecules can chemically link to each other, creating chains of molecules - a polymer. In turn, these abnormal elongated hemoglobin polymer structures distort the shape of the whole red blood cell. The abnormal RBC's can damage the vessels around them and the tissues that depend on the vessels for oxygen and nourishment. For example, the damaged RBC's can cause thrombosis (clotting) and then secondary ischemic damage to the adjacent and surrounding tissues - causing infarction (cellular death). Ironically, the sickle cell trait (the heterozygous HgbSA - not the homozygous HgbSS) seems to have a protective effect against the malaria parasite. By the time many patients reach adulthood, there is often objective evidence of anatomic and/or functional damage to various tissues due to the cumulative effects of recurrent vasoocclusive (clotting) episodes. However, the course of the disease is variable from patient to patient. Learn
More About Sickle Cell Anemia - 1
You may also want to visit the Sickle Cell Anemia Slide Show. |
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| Bone
Changes
Sickle Cell Anemia and its variants produce roentgenographically similar bone changes. These have been divided conveniently into four groups;
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| Cardiovascular
SS Homozygotes frequently develop congestive heart failure. The chronic severe anemia and hypoxemia impose sustained demands on the heart. At the same time, sickle cell patients are in a continuous state of hyperdynamic circulation and therefore, frequently exhibit systolic murmurs. However, even though more oxygen is extracted by the myocardium than any other tissue, SS patients rarely develop myocardial infarction.
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| Treatment
of Sickle Cell Disease
The primary goal of therapy is to reduce the frequency, duration, and severity of the "sickle cell crisis episodes" and to maintain an adequate supply of RBC's to nourish the tissues. Adequate hydration, oxygenation, bone marrow stimulation, and blood transfusion are commonly used to treat sickle cell crisis. Search for information
about Treatment of Sickle Cell Anemia ==> Click
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| Learn
More About Sickle Cell Disease
Learn
More About Sickle Cell Anemia - 1
You may also want to visit the Sickle Cell Anemia Slide Show.
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