Anemia
A. What Is Anemia?
In anemia, the red blood cell (RBC) level in the blood is low. RBCs carry oxygen to the
tissues. Therefore, if RBCs are low, the body’s tissues suffer from a lack of oxygen.
Anemia is common in cancer patients and may be a result of the tumor itself or of the
cancer treatment.
RBCs are produced in the bone marrow and circulate in the blood until they become too
old and are removed by the spleen. Anemia can result from excessive RBC loss due to
bleeding or insufficient RBC production by the bone marrow. If the cells are excessively
destroyed in the blood or spleen, hemolytic anemia is present.
B. Causes
Anemia is a symptom of many underlying diseases. The most common are iron deficiency, acute blood loss, and inflammatory diseases such
as rheumatoid arthritis.
Hypoproliferative anemia. Hypoproliferative anemia can be subdivided into three
classes based upon the size of the RBCs. The cells may be larger than normal (macrocytic),
normal (normocytic), or smaller than normal (microcytic).
Macrocytic anemia. Macrocytic anemia can be due to several causes. The first is
a deficiency in vitamin B12 or folate, both important ingredients in RBC
production. Please see Vitamin B12 Insufficiency
and Folic Acid Insufficiency. It may also be caused by
disease of the bone marrow such as myeloproliferative disorders, inherited bone marrow
diseases, or cancer. Please see Myeloproliferative Disorders and Leukemia.
Normocytic anemia. Normocytic anemia may be due to chronic disease including
malnutrition or mixed anemia (combined macrocytic and microcytic anemia).
Microcytic anemia. Microcytic anemia is due to abnormalities in the production
of the essential RBC protein, hemoglobin. This is often to due to underlying disease, such
as thalassemia.
Hemolytic anemia. Hemolytic anemia may be due to inherited abnormal hemoglobin
(the essential RBC protein; for example, sickle cell anemia), prosthetic heart valves,
infections such as malaria, and disease such as thrombotic thrombocytopenia purpura and
hemolytic-uremic syndrome.
C. Signs and Symptoms
Anemia can affect the body rapidly or be a slow-developing process. If it is due to
rapid blood loss or acute hemolysis, the anemic patient will experience lightheadedness
(due to low blood pressure), weakness, and cardiac strain (with shortness of breath and
shooting pains from the chest). More gradual onset of anemia (chronic anemia) is
accompanied by fatigue, irritability, headache, pain, palpitations (fluttering of
heartbeat), difficulty in breathing especially when lying flat, decreased body
temperature, and elevated heart rate among other symptoms.
For symptoms specific to certain cases of anemia, please see Vitamin B12 Deficiency, Folic Acid Deficiency, and Iron
Deficiency.
D. Diagnosis
Anemia can be diagnosed based upon patient history, physical examination for symptoms,
and laboratory testing. In addition to detecting anemia, determination of the underlying
cause is important for effective treatment.
E. Treatment
Treatment of anemia focuses primarily upon treating the underlying cause of the
condition if possible. In addition, oxygen support or blood transfusions may be used.
