Doctor's Notes on Anemia
Anemia refers to a medical condition in which the red blood cell count or hemoglobin level is less than normal. Anemia can be caused by different medical conditions and is always related to either decreased production of red blood cells or hemoglobin, or an increase in loss or destruction of red blood cells. Iron deficiency anemia is a very common type of anemia and occurs as a result of chronic blood loss for any reason, which depletes the body’s iron stores.
Some people with anemia, especially mild cases of anemia, may not have any symptoms. When symptoms do occur, the most common symptoms are tiredness, fatigue, pale appearance to the skin, shortness of breath, and heart palpitations. Other associated signs and symptoms in some people can include hair loss and worsening of heart problems.
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.
Symptoms of anemia may include the following:
- decreased energy;
- shortness of breath;
- palpitations (feeling of the heart racing or beating irregularly); and
- looking pale.
Symptoms of severe anemia may include:
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; and
- enlargement of the spleen with certain causes of anemia.
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 (Fe) 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. Iron deficiency anemia can also occur when there are stomach ulcers or other sources of slow, chronic bleeding (colon cancer, uterine cancer, intestinal polyps, hemorrhoids, 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 anemia. The exact mechanism of this process in unknown, but any long-standing and ongoing medical condition such as a chronic 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 (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 anemia. This is called anemia related to or anemia of chronic kidney disease.
- Anemia related to pregnancy: Water weight and fluid gain during pregnancy dilutes 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 hemoglobin (Hgb). 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 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 hemoglobin-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 hemoglobin abnormalities, meaning an insufficient amount of the correct hemoglobin 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 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 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.
Anyone Can Have It
This illness means you have a lower than normal red blood cell (RBC) count. Normal values vary; blood tests like the complete blood count (CBC) can be explained by your doctor. Anemia may also result from low levels of hemoglobin, the protein that transports oxygen to the body. No matter what the cause, less oxygen is available and this produces weakness, dizziness, and shortness of breath. It is treatable once the underlying cause is identified. Long-standing or severe lack of oxygen can damage of the brain, heart, and other organs.
The three main causes of the illness are inadequate or faulty production of red blood cells, a high rate of destruction of red blood cells, and excessive bleeding. Megaloblastic is one type of faulty red cell production. The condition of anemia may be mild and easily treatable or severe and require immediate intervention.
Blood and Bleeding Disorders QuizQuestion
Sickle cell disease is named after a farming tool.See Answer
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.