Physician Specialist Glossary

What Is Anemia?

Anemia is a condition that develops when your blood lacks enough healthy red blood cells or hemoglobin. Hemoglobin is a main part of red blood cells and binds oxygen. If you have too few or abnormal red blood cells, or your hemoglobin is abnormal or low, the cells in your body will not get enough oxygen. Symptoms of anemia -- like fatigue -- occur because organs aren't getting what they need to function properly. 

Anemia is the most common blood condition in the U.S. It affects about 3.5 million Americans. Women and people with chronic diseases are at increased risk of anemia. Important factors to remember are:

• Certain forms of anemia are hereditary and infants may be affected from the time of birth.
• Women in the childbearing years are particularly susceptible to iron-deficiency anemia because of the blood loss from menstruation and the increased blood supply demands during pregnancy.
• Older adults also may have a greater risk of developing anemia because of poor diet and other medical conditions.

There are many types of anemia. All are very different in their causes and treatments. Iron-deficiency anemia, the most common type, is very treatable with diet changes and iron supplements. Some forms of anemia -- like the anemia that develops during pregnancy -- are even considered normal. However, some types of anemia may present lifelong health problems.

What Causes Anemia?

There are more than 400 types of anemia, which are divided into three groups:

• Anemia caused by blood loss
• Anemia caused by decreased or faulty red blood cell production
• Anemia caused by destruction of red blood cells

Anemia Caused by Blood Loss

Red blood cells can be lost through bleeding, which can occur slowly over a long period of time, and can often go undetected. This kind of chronic bleeding commonly results from the following:

• Gastrointestinal conditions such as ulcers, hemorrhoids, gastritis (inflammation of the stomach), and cancer
• Use of nonsteroidal anti-inflammatory drugs (NSAIDS) such as aspirinor ibuprofen, which can cause ulcers and gastritis
• Menstruation and childbirth in women, especially if menstrual bleeding is excessive and if there are multiple pregnancies

Anemia Caused by Decreased or Faulty Red Blood Cell Production

With this type of anemia, the body may produce too few blood cells or the blood cells may not function correctly. In either case, anemia can result. Red blood cells may be faulty or decreased due to abnormal red blood cells or a lack of minerals and vitamins needed for red blood cells to work properly. Conditions associated with these causes of anemia include the following:

• Sickle cell anemia
• Iron-deficiency anemia
• Vitamin deficiency
• Bone marrow and stem cell problems
• Other health conditions

Sickle cell anemia is an inherited disorder that affects African-Americans. Red blood cells become crescent-shaped because of a genetic defect. They break down rapidly, so oxygen does not get to the body's organs, causing anemia. The crescent-shaped red blood cells also get stuck in tiny blood vessels, causing pain.

Iron-deficiency anemia occurs because of a lack of the mineral iron in the body. Bone marrow in the center of the bone needs iron to make hemoglobin, the part of the red blood cell that transports oxygen to the body's organs. Without adequate iron, the body cannot produce enough hemoglobin for red blood cells. The result is iron-deficiency anemia. This type of anemia can be caused by:

• An iron-poor diet, especially in infants, children, teens, vegans, and vegetarians
• The metabolic demands of pregnancy and breastfeeding that deplete a woman's iron stores
• Menstruation
• Frequent blood donation
• Endurance training
• Digestive conditions such as Crohn's disease or surgical removal of part of the stomach or small intestine
• Certain drugs, foods, and caffeinated drinks

Vitamin-deficiency anemia may occur when vitamin B12 and folate are deficient. These two vitamins are needed to make red blood cells. Conditions leading to anemia caused by vitamin deficiency include:

• Megaloblastic anemia: Vitamin B12 or folate or both are deficient
• Pernicious anemia: Poor vitamin B12 absorption caused by conditions such as Crohn's disease, an intestinal parasite infection, surgical removal of part of the stomach or intestine, or infection with HIV
• Dietary deficiency: Eating little or no meat may cause a lack of vitamin B12, while overcooking or eating too few vegetables may cause a folate deficiency.
• Other causes of vitamin deficiency: pregnancy, certain medications, alcohol abuse, intestinal diseases such as tropical sprue and celiac disease

During early pregnancy, sufficient folic acid can prevent the fetus from developing neural tube defects such as spina bifida.

Bone marrow and stem cell problems may prevent the body from producing enough red blood cells. Some of the stem cells found in bone marrow develop into red blood cells. If stem cells are too few, defective, or replaced by other cells such as metastatic cancer cells, anemia may result. Anemia resulting from bone marrow or stem cell problems include:

• Aplastic anemia occurs when there's a marked reduction in the number of stem cells or absence of these cells. Aplastic anemia can be inherited, can occur without apparent cause, or can occur when the bone marrow is injured by medications, radiation, chemotherapy, or infection.
• Thalassemia occurs when the red cells can't mature and grow properly. Thalassemia is an inherited condition that typically affects people of Mediterranean, African, Middle Eastern, and Southeast Asian descent. This condition can range in severity from mild to life-threatening; the most severe form is called Cooley's anemia.
• Lead exposure is toxic to the bone marrow, leading to fewer red blood cells. Lead poisoning occurs in adults from work-related exposure and in children who eat paint chips, for example. Improperly glazed pottery can also taint food and liquids with lead.

Anemia associated with other conditions usually occur when there are too few hormones necessary for red blood cell production. Conditions causing this type of anemia include the following:

• Advanced kidney disease
• Hypothyroidism
• Other chronic diseases, such as cancer, infection, lupus, diabetes, and rheumatoid arthritis
• Old age

Anemia Caused by Destruction of Red Blood Cells

When red blood cells are fragile and cannot withstand the routine stress of the circulatory system, they may rupture prematurely, causing hemolytic anemia. Hemolytic anemia can be present at birth or develop later. Sometimes there is no known cause. Known causes of hemolytic anemia may include:

• Inherited conditions, such as sickle cell anemia and thalassemia
• Stressors such as infections, drugs, snake or spider venom, or certain foods
• Toxins from advanced liver or kidney disease
• Inappropriate attack by the immune system (called hemolytic disease of the newborn when it occurs in the fetus of a pregnant woman)
• Vascular grafts, prosthetic heart valves, tumors, severe burns, chemical exposure, severe hypertension, and clotting disorders
• In rare cases, an enlarged spleen can trap red blood cells and destroy them before their circulating time is up.

The goal of treatment for leukemia is to destroy the leukemia cells and allow normal cells to form in your bone marrow. Treatment decisions are based on the kind of leukemia you have, its stage, and your age and general health.

Treatment for acute leukemia

Chemotherapy is the use of drugs to fight cancer. It is the usual treatment for acute leukemia. For most people, that means receiving drugs in stages:

• The goal of induction is to kill leukemia cells in the blood and bone marrow to induce remission. During remission, there are no signs or symptoms of leukemia.
• The goal of consolidation is to kill any leukemia cells that may be present even though they don't show up in tests. If these cells regrow, they could cause a relapse.
• The goal of maintenance also is to prevent any remaining leukemia cells from growing. This may be done using lower doses of chemotherapy than those used during induction or consolidation. This is only used in people with ALL and a few rare forms of AML.

Some types of acute leukemia spread to the brain and spinal cord. Regular chemotherapy cannot reach those areas, because your body puts up a special barrier to protect them. A different way of giving chemotherapy, called intrathecal chemotherapy, treats these areas by injecting the drugs directly into your spinal canal to attack any leukemia cells there.

Radiation therapy uses high doses of radiation, such as X-rays, to destroy cancer cells. Radiation is usually given from a machine outside the body that directs radiation to the cancer (external radiation). Radiation is also used to treat acute leukemia that has spread to the brain and spinal cord.

Stem cell transplant may be part of the treatment plan for people who have high-risk acute leukemia. Most stem celltransplants for leukemia are allogeneic, meaning the stem cells are donated by someone else. The goal of a transplant is to destroy all the cells in your bone marrow, including the leukemia cells, and replace them with new, normal cells.

Treatment if acute leukemia gets worse

Sometimes leukemia gets worse in spite of treatments. Sometimes it gets better, or "goes into remission." Sometimes it comes back, or "relapses." Even when that happens, there are several treatments that may help to cure the leukemia or help you live longer:

• Stem cell transplant. Donated cells from a "matched" donor can rebuild your supply of normal blood cells and your immune system.
• Chemotherapy. Sometimes medicines or doses that are different from those used during your initial chemotherapy can help.

Clinical trials. People who have leukemia may enter a research program when they first start treatment or if the leukemia is not getting better. These programs test new ways to treat the disease. For more information, see www.cancer.gov/clinical_trials/ or http://clinicaltrials.gov.

For more information about acute leukemias in adults, see the following topics:

• Adult Acute Lymphoblastic Leukemia Treatment [NCI PDQ]-Health Professional Version
• Adult Acute Lymphoblastic Leukemia Treatment [NCI PDQ]-Patient Version
• Adult Acute Myeloid Leukemia Treatment [NCI PDQ]-Health Professional Version
• Adult Acute Myeloid Leukemia Treatment [NCI PDQ]-Patient Version

Treatment of chronic leukemia

Chronic lymphocytic leukemia (CLL)

Chronic lymphocytic leukemia is not always treated right away. It usually gets worse more slowly than acute leukemia.

Treatment choices for CLL include:

• Watchful waiting. CLL usually gets worse very slowly, and you may have no symptoms for some time. You and your doctor may decide to hold off on treatment for a while. During this time your doctor will watch you carefully.
• Radiation therapy. Radiation may be used to destroy cancer cells. It also may be used to shrink swollen lymph nodes or a swollen spleen. Sometimes radiation is used on the whole body to prepare for a bone marrow transplant.
• Chemotherapy. Chemotherapy is the use of medicines that attack cancer cells. Many medicines are available to fight leukemia and help you live longer.
• Surgery. If the spleen starts destroying red blood cells and platelets, it may need to be removed. This operation is called a splenectomy.
• Targeted therapy with a monoclonal antibody. These antibodies can kill cancer cells, stop their growth, or keep them from spreading.

When you have CLL, your body is not able to fight infections very well. You and your doctor need to watch for any signs of infections, such as pneumonia or yeast infections. Early treatment of these and other infections will help you live longer. You can sometimes prevent certain infections or keep from getting very sick by getting a flu shot or a pneumonia vaccine. Your doctor also may give you antibiotics to prevent infection while you are being treated for leukemia.

Chronic myelogenous leukemia (CML)

Chronic myelogenous leukemia is treated right away.

Treatment choices for CML include:

• Targeted therapy with a tyrosine kinase inhibitor, such as imatinib or dasatinib, is the first treatment used for CML.
• Chemotherapy. Chemotherapy is the use of medicines that attack cancer cells. Many medicines are available to fight leukemia and help you live longer.
• Biological therapy. This is the use of special medicines that improve your body's natural defenses against cancer.
• High-dose chemotherapy with stem cell transplant. After chemotherapy is completed, stem cells that were previously donated and frozen are thawed and infused.
• Donor lymphocyte infusion (DLI). This is a treatment that may be used after a stem cell transplant. With DLI, a person is given more of their donor's white blood cells (lymphocytes).
• Surgery. If the spleen starts destroying red blood cells and platelets, it may need to be removed. This operation is called a splenectomy.

Clinical trials are used to find out whether a medicine or treatment is safe and effective. People who have chronic leukemia are often referred to clinical trials for their treatment. For more information, see www.cancer.gov/clinical_trials/ or http://clinicaltrials.gov.

For more information about chronic leukemias in adults, see the following topics:

• Chronic Lymphocytic Leukemia Treatment [NCI PDQ] - Health Professional Version
• Chronic Lymphocytic Leukemia Treatment [NCI PDQ] - Patient Version
• Chronic Myelogenous Leukemia Treatment [NCI PDQ] - Health Professional Version
• Chronic Myelogenous Leukemia Treatment [NCI PDQ] - Patient Version

For information about hairy cell leukemia, see the following topics:

• Hairy Cell Leukemia Treatment [NCI PDQ] - Health Professional Version
• Hairy Cell Leukemia Treatment [NCI PDQ] - Patient Version

Leukemia in children

Treatments for children who have leukemia are not the same as treatments for adults who have leukemia. Children may respond and react to treatments in ways that are different from how adults respond. Also, after the leukemia has been treated, children may need to be monitored for treatment side effects that may appear months or years later.

Leukemia in children is usually treated by a medical team led by a pediatric oncologist.

For more information about childhood leukemias, see the following topics:

• Childhood Acute Lymphoblastic Leukemia Treatment [NCI PDQ] - Health Professional Version
• Childhood Acute Lymphoblastic Leukemia Treatment [NCI PDQ] - Patient Version
• Childhood Acute Myeloid Leukemia/Other Myeloid Malignancies Treatment [NCI PDQ] - Health Professional Version
• Childhood Acute Myeloid Leukemia/Other Myeloid Malignancies Treatment [NCI PDQ] - Patient Version

Palliative care

If you have leukemia, you may want to consider having palliative care along with your treatments. Palliative care is a kind of care for people who have serious illnesses. It can help you manage symptoms from your treatment. Palliative care focuses on improving your quality of life-not just in your body but also in your mind and spirit.

Palliative care may help you manage symptoms or side effects from treatment. It could also help you cope with your feelings about living with a serious illness, make future plans for your medical care, or help your family better understand your illness and how to support you.

If you are interested in palliative care, talk to your doctor. He or she may be able to manage your care or refer you to a doctor who specializes in this type of care.

For more information, see the topic Palliative Care.

End-of-life issues

Even if your treatment is going well, it's a good idea to plan ahead. Talk to your family and your doctor about health care and other legal issues that arise near the end of life. Put your health care choices in writing (with an advance directive or living will). This is important, if a time comes when you can't make and communicate these decisions. Think about your treatment options and which kind of treatment will be best for you. You may also want to choose a health care agent to make and carry out decisions about your care if you become unable to speak for yourself.

For more information, see the topics Writing an Advance Directive and Choosing a Health Care Agent.

A time may come when your goals may change from treating an illness to maintaining your comfort and dignity. Your doctor can address questions or concerns about maintaining your comfort when cure is no longer an option. Hospice care professionals can provide palliative care in the comfortable surroundings of your own home.

For more information, see the topics Palliative Care, Hospice Care, and Care at the End of Life.

What to think about

When leukemia has been in remission for a long time, the word "cure" is often used. Your doctor may use the term "remission" instead of "cure" when talking about the effectiveness of your treatment. Although many people who have leukemia are successfully treated, the term remission is used because cancer can return (recur). It is important to discuss the possibility of recurrence with your doctor.

Clinical trials play a very important part in the treatment of leukemia. Clinical trials test the latest drugs and other new treatments. They have made it possible for many people with leukemia to live longer. People who are in clinical trials get all the recommended treatments for their cancer and are closely watched. Talk to your doctor about whether there is a clinical trial that might be good for you. For more information, see www.cancer.gov/clinical_trials/ or http://clinicaltrials.gov.