Hemoglobin, a protein within red blood cells, carries oxygen to the tissues. When the hemoglobin level decreases, it results in anemia. Typical symptoms include fatigue and shortness of breath. If the anemia is mild or develops over a long period, noticeable symptoms may be absent. But sudden or severe anemia can lead to paleness, heart failure and could be fatal. A low hemoglobin can result from decreased production or increased destruction of red blood cells, bone marrow problems, or acute or chronic blood loss.
Iron deficiency is one of the most common causes of low hemoglobin. Iron is an important component of the hemoglobin molecule and without sufficient iron intake, the body cannot produce adequate amounts of hemoglobin. Iron deficiency is the most common nutritional deficiency in the world and a leading cause of anemia, notes an article in the April 2011 issue of the "Annals of Hematology."
A deficiency in vitamin B12, also called folate, can also lead to anemia. Another condition, aplastic anemia, shuts down the bone marrow, the tissue inside bones that produces red blood cells. Other conditions that affect the bone marrow’s ability to produce red blood cells include leukemia, lymphoma and other blood cancers.
Increased destruction of red blood cells can lead to decreased hemoglobin and anemia. Hemolytic anemia is an autoimmune condition in which the body attacks its own red blood cells, mistakenly identifying the cells as foreign. People with other hereditary conditions, such as sickle cell disease and thalassemia, have increased red blood cell destruction because those diseases change the shape of the red blood cells in a way that makes them more fragile.
Anemia of Chronic Disease
Long-term medical conditions can adversely affect the interplay of the bone marrow and the rest of the body, leading to a condition called anemia of chronic disease. According to an article in the May 2011 issue of "British Journal of Haematology," anemia of chronic disease is the second most common form of anemia.
With anemia of chronic disease, medical professionals theorize that chronic inflammation decreases the capacity of the bone marrow to produce red blood cells and incorporate the iron necessary for the production of hemoglobin, leading to anemia. There are many causes of anemia of chronic disease, including infections, such as hepatitis B and C and HIV/AIDS; cancers, such as lymphoma; autoimmmune conditions, such as Crohn disease and lupus; and chronic kidney disease.
Anemia Due to Blood Loss
Anemia due to blood loss can be acute or chronic. Sudden blood loss as a result of trauma, internal bleeding or surgery can lead to life-threatening anemia that requires prompt replacement with blood transfusion. Chronic blood loss can occur when a woman has persistently heavy menstrual periods, or if a person has slow bleeding from the gastrointestinal tract from an ulcer or diverticulitis, for example.
- Annals of Hematology: Anemia -- Still a Major Health Problem in Many Parts of the World!
- British Journal of Haematology: Diagnosis and Management of Anaemia of Chronic Disease: Current Status
- Hematology: Clinical Principles and Applications; Bernadette F. Rodak