Anemia is a condition in which the body does not have enough healthy red blood cells to carry oxygen to the bodys organs. Severe anemia is a more advanced stage of anemia that can cause low oxygen levels in vital organs such as the heart, and can lead to heart failure. Anemia can be caused by various factors, including:

• Vitamin deficiency anemia: This can occur when the body cant absorb vitamin B-12, leading to a deficiency in vitamin B-12, also called pernicious anemia.
• Anemia of inflammation: This can occur when diseases cause ongoing inflammation that keeps the body from making enough red blood cells. Examples of such diseases are cancer, HIV/AIDS, rheumatoid arthritis, kidney disease, and Crohns disease.
• Aplastic anemia: This is a rare, life-threatening anemia that occurs when the body doesnt make enough new blood cells. Causes of aplastic anemia include infections, certain medicines, autoimmune diseases, and being in contact with toxic chemicals.
• Hemolytic anemias: This group of anemias is from red blood cells being destroyed faster than bone marrow can replace them. Hemolytic anemia may be due to mechanical causes, infections, autoimmune disorders, or congenital abnormalities in the red blood cell.

Anemia can be classified into acute anemia and chronic anemia. Acute anemia is predominantly due to acute blood loss or acute hemolysis. Chronic anemia is more common and is secondary to multiple causes. The grading of anemia, according to the National Cancer Institute, is as follows:

• Mild: Hemoglobin 10.0 g/dL to lower limit of normal
• Moderate: Hemoglobin 8.0 to 10.0 g/dL
• Severe: Hemoglobin 6.5 to 7.9 g/dL
• Life-threatening: Hemoglobin less than 6.5 g/dL

If you have any symptoms of anemia or unusual bleeding, you should contact your healthcare provider. Treatment for anemia depends on the type and severity of the condition. Treatment options may include supplements of iron, vitamin B12, folic acid, or other vitamins and minerals, corticosteroids, or other medicines that suppress the immune system, and erythropoietin, a medicine that helps your bone marrow make more blood cells.