s having a low blood count. A person who has anaemia is called anaemic.
What is Anemia?
Blood is comprised of two parts: a liquid called the plasma and a cellular part. The cellular part contains several different cell types. One of the most important and the most numerous cell types are red blood cells. 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 the femur and pelvic 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 bloodstream. The haemoglobin molecule is the functional unit of the red blood cells and is a complex protein structure that is inside the red blood cells. Contrary to most cells in the human body, red blood cells do not have a nucleus (metabolic centre of a cell).
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 haemoglobin molecule; erythropoietin, a molecule secreted by the kidneys, promotes the formation of red blood cells in the bone marrow.Anaemia or Anemia Click To Tweet
Facts of Anemia and Red Blood Cells
- Having the correct number of red blood cells and the prevention of anaemia requires cooperation among the kidneys, the bone marrow, and nutrients within the body. If the kidneys or bone marrow are not functioning, or the body is poorly nourished, then normal red blood cell count and function may be difficult to maintain.
- Anaemia is actually a sign of a disease process rather than bring a disease itself. It is usually classified as either chronic or acute. Chronic anaemia occurs over a long period of time. Acute anaemia occurs quickly. Determining whether anaemia has been present for a long time or whether it is something new, assists doctors in finding the cause. This also helps predict how severe the symptoms of anaemia may be. In chronic anaemia, symptoms typically begin slowly and progress gradually; whereas in acute anaemia symptoms can be abrupt and more distressing.
- Red blood cells live about 100 days, so the body is constantly trying to replace them. In adults, red blood cell production occurs in the bone marrow. Doctors try to determine if a low red blood cell count is caused by increased blood loss of red blood cells or from decreased production of them in the bone marrow. Knowing whether the number of white blood cells and/or platelets has changed also helps determine the cause of anaemia.
- Young women are twice as likely to have anaemia than young men because of regular menstrual bleeding. Anemia occurs in both young people and in old people, but anaemia in older people is more likely to cause symptoms and be related to serious, underlying conditions.
- In general, there are three major types of anaemia, classified according to the size of the red blood cells:
- If the red blood cells are smaller than normal, this is called microcytic anaemia. The major causes of this type are iron deficiency (low-level iron) anaemia and thalassemia (inherited disorders of haemoglobin).
- If the red blood cells size is normal in size (but low in number), this is called normocytic anaemia, such as anaemia that accompanies chronic disease or anaemia related to kidney disease.
- If red blood cells are larger than normal, then it is called macrocytic anaemia. Major causes of this type are pernicious anaemia and anaemia related to alcoholism.
Causes of Anemia
Many medical conditions cause anemia. Common causes of anaemia include the following:
- Anemia from active bleeding: Loss of blood through heavy menstrual bleeding or wounds can cause anaemia. Gastrointestinal ulcers or cancers such as cancer of the colon may slowly ooze blood and can also cause anemia.
- Iron deficiency anaemia: The bone marrow needs iron to make red blood cells. Iron (Fe) plays an important role in the proper structure of the haemoglobin molecule. If iron intake is limited or inadequate due to poor dietary intake, anaemia may occur as a result. This is called iron deficiency anaemia. Iron deficiency anaemia can also occur when there are stomach ulcers or other sources of slow, chronic bleeding (colon cancer, uterine cancer, intestinal polyps, haemorrhoids, etc). In these kinds of scenarios, because of ongoing, chronic slow blood loss, iron is also lost from the body (as a part of blood) at a higher rate than normal and can result in iron deficiency anemia.
- Anemia of chronic disease: Any long-term medical condition can lead to anaemia. The exact mechanism of this process in unknown, but any long-standing and ongoing medical condition such as chronic infection or cancer may cause this type of anaemia.
- Anaemia 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 (CKD or end stage renal disease(ESRD), the production of this hormone is diminished, and this, in turn, diminishes the production of red blood cells, causing anaemia. This is called anaemia related to or anemia of chronic kidney disease.
- Anaemia related to pregnancy: Water weight and fluid gain during pregnancydilutes the blood, which may be reflected as anemia since the relative concentration of red blood cells is lower.
- Anemia related to poor nutrition: Vitamins and minerals are required to make red blood cells. In addition to iron, vitamin B12 and folate (or folic acid) are required for the proper production of haemoglobin (Hgb). Deficiency in any of these may cause anaemia because of the 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 the production of abnormal haemoglobin molecules. In this condition, the haemoglobin problem is qualitative, or functional. Abnormal haemoglobin 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 cell anemia with different severity levels. This is typically hereditary and is more common in those of African, Middle Eastern, and Mediterranean ancestry. People with sickle cell anemia can be diagnosed as early as childhood depending on the severity and symptoms of their disease.
- Thalassemia: This is another group of haemoglobin-related causes of anemia. There are many types of thalassemia, which vary in severity from mild (thalassemia minor) to severe (thalassemia major). These are also hereditary, but they cause quantitative haemoglobin abnormalities, meaning an insufficient amount of the correct haemoglobin molecules is made. Thalassemia is more common in people from African, Mediterranean, and Southeast Asian ancestries.
- 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 anaemia in alcoholics.
- Bone marrow-related anemia: Anemia may be related to diseases involving the bone marrow. Some blood cancers such as leukaemia or lymphomas can alter the production of red blood cells and result in anaemia. Other processes may be related to cancer from another organ spreading to the bone marrow.
- Aplastic anemia: Occasionally some viral infections may severely affect the bone marrow and significantly 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 (for example, as in hereditary spherocytosis, hereditary elliptocytosis, and glucose-6-phosphate dehydrogenase or G6GD deficiency). This type of destruction may also happen to normal red blood cells in certain conditions, for example, with abnormal heart valves damaging the blood cells or certain medications that disrupt the red blood cell structure.
- Anemia related to medications: Many common medications can occasionally cause anemia as a side effect in some individuals. The mechanisms by which medications can cause anemia are numerous (hemolysis, bone marrow toxicity) and are specific to the medication. Medications that most frequently cause anemia are chemotherapy drugs used to treat cancers (chemotherapy-induced anemia). Other common medications that can cause anemia include some seizure medications, transplant medications, HIV medications, some malaria medications, some antibiotics(penicillin, chloramphenicol), antifungal medications, and antihistamines.
- Other less common causes of anemia include thyroid problems, cancers, liver disease, autoimmune diseases (lupus), paroxysmal nocturnal hemoglobinuria (PNH), lead poisoning, AIDS, malaria, viral hepatitis, mononucleosis, parasitic infections (hookworm), bleeding disorders, and insecticide exposure. It is noteworthy that there are many other potential causes of anemia that are not included in this list as these are only some of the more common and important ones.
Symptoms of Anemia
Because a low red blood cell count decreases oxygen delivery to every tissue in the body, anemia can cause a variety of signs and symptoms. It can also worsen the symptoms of almost any other underlying medical condition. 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.
11 Common symptoms of anemia
- decreased energy
- shortness of breath
- palpitations(feeling of the heart racing or beating irregularly)
- looking pale.
- chest pain, angina, or heart attack
- fainting or passing out
- rapid heart rate.
8 Signs of Anemia
- Change in stool colour, including black and tarry stools(sticky and foul smelling), maroon-coloured, 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; and
- enlargement of the spleen with certain causes of anemia.
How to diagnose Anemia?
Doctors can easily detect anemia by drawing a blood sample for a complete blood count. Based on the results of the test and thorough evaluation of the patient, the doctor may order more tests to determine the exact cause of anemia. The complete blood count may be done as part of a routine general check-up or based upon the presence of signs and symptoms suggestive of anemia.
Physical examination and medical history also play a crucial role in diagnosing causes of anemia. Some of the important features in medical history cover questions about family history, previous personal history of anemia or other chronic conditions, medications, colour of stool and urine, bleeding problems, and occupation and social habits (such as alcohol intake).
Complete blood count (CBC): Determines the severity and type of anemia (microcytic anemia or small-sized red blood cells, normocytic anemia or normal-sized red blood cells, or macrocytic anemia or large-sized red blood cells) and is typically the first test ordered. Information about other blood cells (white cells and platelets) is also included in the CBC report. Haemoglobin (Hgb) and hematocrit (Hct) measurements in a complete blood count test are commonly used to diagnose anemia. They measure the amount of haemoglobin, which an accurate reflection of red blood cell (RBC) quantity in the blood.
Stool haemoglobin test: Tests for blood in the stool may detect bleeding from the stomach or the intestines (stool Guaiac test or stool occult blood test).
Peripheral blood smear: Looks at the red blood cells under a microscope to determine the size, shape, number, and appearance as well as evaluate other cells in the blood.
Iron level: A serum iron level may tell the doctor whether anemia may be related to iron deficiency or not. This test is usually accompanied by other tests that measure the body’s iron storage capacity, such as transferrin level and ferritin level.
Transferrin level: Evaluates a protein that transports iron in the body.
Ferritin: Evaluates at the total iron available in the body.
Folate (Folic Acid): A vitamin needed to produce red blood cells, which is low in people with poor eating habits.
Vitamin B12: A vitamin needed to produce red blood cells and low in people with poor eating habits or in pernicious anemia.
Bilirubin: Useful to determine if the red blood cells are being destroyed within the body which may be a sign of hemolytic anemia.
Lead level: Lead toxicity was formerly one of the more common causes of anemia in children.
Haemoglobin electrophoresis: Sometimes used when a person has a family history of anemia; this test provides information on sickle cell anemia or thalassemia.
Reticulocyte count: A measure of new red blood cells produced by the bone marrow
Liver function tests: A common test to determine how the liver is working, which may give a clue to other underlying disease causing anemia.
Kidney function test: A test that is very routine and can help determine whether any kidney dysfunction exists. Kidney failure can result in erythropoietin (Epo) deficiency, leading to anemia.
Bone marrow biopsy: Evaluates production of red blood cells and may be done when a bone marrow problem is suspected.
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