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.
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
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.
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.
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.
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.