Anemia حصيلة 5 الدفعة التانية

Overview
Anemia describes the condition in which the number of red blood cells in the blood is low. For this reason, doctors sometimes describe someone with anemia as having a low blood count. A person who has anemia is called anemic.
Blood is comprised of two parts; a liquid part called the plasma and a cellular part. The cellular part contains several different cell types. One of the most important and most numerous cell types is the red blood cell. The other cell types are the white blood cells and platelets. Only red blood cells are discussed in this article. The purpose of the red blood cell is to deliver oxygen from the lungs to other parts of the body.
Red blood cells are produced through a series of complex and specific steps. They are made in the bone marrow (inner part of some bones that make most of the cells in the blood), and when all the proper steps in their maturation are complete, they are released into the blood stream. The hemoglobin molecule is the functional unit of the red blood cells and is the protein structure that is inside the red blood cells.
Even though the red blood cells (or RBCs) are made within the bone marrow, many other factors are involved in their production. For example, iron is a very important component of the hemoglobin molecule; erythropoietin, a molecule secreted by the kidneys, promotes the formation of red blood cells in the bone marrow.



Anemia Causes


Many medical conditions cause anemia. Common causes of anemia include the following:

• Anemia from active bleeding: Loss of blood through heavy menstrual bleeding or, wounds can cause anemia. Gastrointestinal ulcers or cancers such as cancer of the colon may slowly ooze blood and can also cause anemia.
  
• Iron deficiency anemia: The bone marrow needs iron to make red blood cells. Iron plays an important role in the proper structure of the hemoglobin molecule. If iron intake is limited or inadequate due to poor dietary intake, anemia may occur as a result. This is called iron deficiency anemia.
  
• Anemia of of chronic disease: Any long-term medical condition can lead to anemia. The exact mechanism of this process in unknown, but any long-standing and ongoing medical condition such as an infection or a cancer may cause this type of anemia.
  
• Anemia related to kidney disease: The kidneys release a hormone called the erythropoietin that helps the bone marrow make red blood cells. In people with chronic (long-standing) kidney disease, the production of this hormone is diminished, and this in turn diminishes the production of red blood cells, causing anemia. This is called anemia related to chronic kidney disease.
  
• Anemia related to pregnancy: Water weight gain during pregnancy dilutes the blood, which may be reflected as anemia.
  
• Anemia related to poor nutrition: Vitamins and minerals are required to make red blood cells. In addition to iron, vitamin B12 and folate are required for the proper production of hemoglobin. Deficiency in any of these may cause anemia because of inadequate production of red blood cells. Poor dietary intake is an important cause of low folate and low vitamin B12 levels. Strict vegetarians who do not take sufficient vitamins are at risk to develop vitamin B12 deficiency.
  
• Pernicious Anemia: There also may be a problem in the stomach or the intestines leading to poor absorption of vitamin B12. This may lead to anemia because of vitamin B12 deficiency known as pernicious anemia.
  
• Sickle cell anemia: In some individuals, the problem may be related to production of abnormal hemoglobin molecules. In this condition the hemoglobin problem is qualitative, or functional. Abnormal hemoglobin molecules may cause problems in the integrity of the red blood cell structure and they may become crescent-shaped (sickle cells). There are different types of sickle call anemia with different severity levels. This is typically hereditary and is more common in those of African, Middle Eastern, and Mediterranean ancestry.
  
• Thalassemia: this is another group of hemoglobin-related causes of anemia. There are many types of thalassemia, which vary in severity. These are also hereditary, but they cause quantitative hemoglobin abnormalities, meaning an insufficient number of hemoglobin molecules is made.
  
• Alcoholism: Poor nutrition and deficiencies of vitamins and minerals are associated with alcoholism. Alcohol itself may also be toxic to the bone marrow and may slow down the red blood cell production. The combination of these factors may lead to anemia in alcoholics.
  
• Bone marrow-related anemia: Anemia may be related to diseases involving the bone marrow. Some blood cancers such as leukemia or lymphomas can alter the production of red blood cells and result in anemia. Other processes may be related to a cancer from another organ spreading to the bone marrow.
  
• Aplastic anemia: Occasionally some viral infections may severely affect the bone marrow and diminish production of all blood cells. Chemotherapy (cancer medications) and some other medications may pose the same problems.
  
• Hemolytic anemia: The normal red blood cell shape is important for its function. Hemolytic anemia is a type of anemia in which the red blood cells rupture (known as hemolysis) and become dysfunctional. This could happen due to a variety of reasons. Some forms of hemolytic anemia can be hereditary with constant destruction and rapid reproduction of red blood cells. This destruction may also happen to normal red blood cells in certain conditions, for example, with abnormal heart valves damaging the blood cells.
  
• Other less common causes of anemia include medication side effects, thyroid problems, cancers, liver disease, other genetic disorders, lead poisoning, AIDS, and bleeding disorders. It is noteworthy that there are many other potential causes of anemia that are not included in this list and these are only some of the more common and important ones.
  Anemia Symptoms
  
  
  Because a low red blood cell count decreases oxygen delivery to every tissue in the body, anemia may cause many signs and symptoms. It can also make almost any other underlying medical condition worse. If anemia is mild, it may not cause any symptoms. If anemia is slowly ongoing (chronic), the body may adapt and compensate for the change; in this case there may not be any symptoms until the anemia becomes more severe.
  Symptoms of anemia may include the following:
  
  
  
  • Fatigue
    
  • weakness
    
  • shortness of breath
    
  • lightheadedness
    
  • palpitations (feeling of the heart racing or beating irregularly)
    
  • looking pale
    
  
  Symptoms of severe anemia may include:
  
  
  
  • chest pain, angina, or heart attack
    
  • dizziness
    
  • fainting or passing out
    
  • rapid heart rate
    
  
  Some of the signs that may indicate anemia in an individual may include:
  
  
  
  • Change in stool color, including black and tarry stools (sticky and foul smelling), maroon-colored, or visibly bloody stools if the anemia is due to blood loss through the gastrointestinal tract.
    
  • rapid heart rate
    
  • low blood pressure
    
  • rapid breathing
    
  • pale or cold skin
    
  • yellow skin called jaundice if anemia is due to red blood cell breakdown
    
  • heart murmur
    
  • enlargement of the spleen with certain causes of anemia
    
  
  

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