Acute Myelogenous Leukemia (AML)
What is acute myelogenous leukemia?
Acute myelogenous leukemia (AML), also called acute myeloid leukemia or acute myelocytic leukemia, is the second most common blood cancer in children. AML affects about 500 children in the U.S. each year. There are several subtypes of AML.
Each AML subtype starts in the young cells that form normal mature blood cells. One subtype, acute promyelocytic leukemia, is treated differently than the other types of AML.
Signs and symptoms of AML
The most common signs and symptoms of acute myelogenous leukemia in children are:
- Anemia. Anemia occurs when normal red blood cells can't be produced because the bone marrow is overcrowded by leukemia cells. The anemic child may be more tired, take more naps, look pale, and her heart may be racing. The number of red blood cells on a blood count (expressed as "hemoglobin" or "hematocrit") will be below normal.
- Bleeding and/or bruising. When the bone marrow cannot produce enough platelets, bleeding can occur, especially when the platelet numbers are less than 10-20,000/mm3. Low platelets can cause a child to bruise or bleed more easily.
- Bone and joint pain. Pain in bones and joints is usually a result of the bone marrow being crowded with leukemic blasts. This is often mistaken for "growing pains."
- Recurrent fevers/infections. The child with leukemia often shows non-specific symptoms of infection such as fever and fatigue. Although the blood count of a child with leukemia may show a high number of white blood cells, these cells are immature and do not normally fight infection. As a result, the child may have difficulty recovering from an ordinary childhood infection or may develop unusual infections.
- Abdominal pain. Leukemia cells can collect in the kidneys, liver and spleen, causing enlargement of these organs which can cause pain in the abdomen. This pain may lead to loss of appetite and weight loss.
- Swollen lymph nodes. Lymph nodes filter the blood. Leukemia cells often collect in the nodes, causing swelling. Swelling occurs in lymph nodes in the neck, under the arms, in the groin and chest. Sometimes it is difficult to distinguish the lymph nodes of leukemia from those that are a normal part of the body's response to infection or allergy.
- Difficulty breathing. In leukemia, cells can clump together in the thymus a gland under the breastbone and around the throat. This mass of cells can cause difficulty breathing. Any wheezing, coughing and/or labored or painful breathing requires immediate medical attention.
Diagnosis of AML
The diagnosis of acute myelogenous leukemia in children is based on a complete medical history and physical examination and on the following diagnostic tests:
- Complete blood count (CBC). The CBC checks the numbers of white blood cells, red blood cell, and platelets in the blood. In leukemia, the white cell count may be lower or higher than normal and the red blood cell count and platelet count is often lower than normal.
- Bone marrow aspirate and biopsy. Bone marrow aspirates and biopsies involve inserting a needle into a bone in the pelvis and removing about 2 teaspoons of marrow for examination. Bone marrow studies require pain medicine and often sedation or general anesthesia.
- Lumbar puncture (spinal tap). Spinal taps involve inserting a needle into the lower back, between the bones of the backbone to remove the fluid that surrounds the brain and spinal cord. The same needle can be used to give chemotherapy to prevent or treat leukemia in the brain or spinal cord.
- Chest X-ray. Chest X-rays are taken to see if there is a mass of leukemia cells in the chest that may affect breathing.
Treatment for AML
Treatment for acute myelogenous leukemia usually begins by addressing the signs and symptoms your child has such as anemia, bleeding and/or infection. In addition, treatment for leukemia may include some or all of the following:
- Chemotherapy. Chemotherapy refers to medicines that help fight cancer. They are given by mouth, in the vein, in the muscle or under the skin. Intrathecal chemotherapy is chemotherapy that is injected into the spinal fluid to prevent or treat leukemia in the brain and spinal cord.
- Blood and marrow transplantation. Blood and marrow transplantation consists of three steps: 1) collection of healthy stem cells from a donor without cancer or from the patient himself or herself; 2) administration of high doses of chemotherapy and possibly radiation therapy to kill any remaining leukemia cells; and 3) infusion of the healthy stem cells through an intravenous line to produce normal blood-forming cells. Bone marrow or stem cell transplantation is commonly used to treat AML that has not responded to chemotherapy.
- Blood transfusions. Blood transfusions are sometimes used for patients who have anemia who cannot make their own red blood cells. Platelets are commonly transfused when platelet counts are low. White blood cells are occasionally transfused to treat severe infections that do not respond to antibiotics. Plasma, the fluid part of blood in which the blood cells are suspended, is transfused in patients who are not able to make the proteins that clot the blood.
- Antibiotics. Antibiotics are used to prevent or treat infections.
Treatment of pediatric AML takes six to nine months and involves three or four courses of chemotherapy and may also involve stem cell transplantation.