What is anemia?
Anemia is a term that describes a condition in which the body has insufficient amount of red blood cells or hemoglobin concentration to carry oxygen to tissues and organs. Hemoglobin is the main protein content of red blood cells that binds to oxygen and gives blood its red color.
Anemia is the most common blood condition affecting about 3.5 million Americans. Children, women and people with chronic diseases are at increased risk of anemia. There are many types of anemia. All are very different in their causes and treatments. Some types of anemia may be inherited and present lifelong health problems, while others are acquired and transient. Although more than 400 types of anemia have been identified, it can be divided into three main groups:
- Anemia caused by blood loss. Examples are acute bleeding with trauma or chronic bleeding from gastrointestinal tract or excessive menstruation.
- Anemia caused by decreased or faulty red blood cell production. Examples are anemia from nutritional deficiencies such as iron, folate and vitamin B12, an inherited blood disorder called thalassemia, and anemia caused by bone marrow failure.
- Anemia caused by destruction of red blood cells. Examples are sickle cell anemia, hereditary spherocytosis, G6PD deficiency, and autoimmune hemolytic anemia.
The diagnosis of anemia is based on a low hemoglobin or hematocrit noted on a complete blood count (CBC). The basis for “low” hemoglobin is according to established normal range for the age of the child. It is important to note that normal ranges for hemoglobin/hematocrit in the pediatric age groups vary as children develop from infancy to adolescence. The hemoglobin values can also vary according to race and gender. Black children tend to have lower hemoglobin compared to whites, and female adolescents have lower values compared to males.
Anemia in children is frequently diagnosed as an incidental finding when a child gets a CBC during routine well-child visit at the pediatrician’s office. Occasionally, children are diagnosed when they present with signs and symptoms of anemia such as pallor, listlessness, or fatigue. As mentioned above, anemia is not a specific disease entity but is a condition caused by different underlying disease processes. Therefore, approach to diagnosis and treatment is based on finding the cause of anemia by doing thorough history and examination, and further laboratory work-up.
A useful initial approach is by determining whether the anemia is caused by one of the three main groups described above: blood loss, decreased red blood cell production or increased red blood cell destruction by adding a reticulocyte count to the CBC. The reticulocyte count gives the percentage of young red blood cells in the blood circulation. This is typically high when there is blood loss or when anemia is caused by increased destruction of the red blood cells, but low when there is faulty red blood cell production in the bone marrow. A review of other red blood cell indices in the CBC such as the MCV, as well as looking at the appearance of the red blood cells on the blood smear also help determine the type of anemia.
Further laboratory tests are then performed depending on the suspected cause of the anemia. In rare cases, a bone marrow examination may be necessary.