Hematological Alterations: Acute Myeloid Leukemia

HEMATOLOGICAL ALTERATIONS

Acute Myeloid Leukemia

DEFINITION • Also known as acute myelogenous leukemia, acute myeloblastic leukemia, acute granulocytic leukemia, or acute nonlymphocytic leukemia • Is a cancer of the myeloid line of blood cells, characterized by the rapid growth of abnormal white blood cells that accumulate in the bone marrow and interfere with the production of normal blood cells. • Is the most common acute leukemia affecting adults, and its incidence increases with age.

• Acute Myeloid Leukemia

ETIOLOGY • Genetic Predisposition  Chromosomal instability in several autosomal dominant conditions can lead to AML, including Fanconi's anemia, ataxia-telangiectasia, neurofibromatosis, and Bloom's syndrome.  Germ line mutations in the AML-1 gene are known to be associated with an increased risk of the development of AML.  Additionally, congenital immunodeficiency disorders including infantile X-linked agammaglobulinemia and Down syndrome, have also been associated with an increased incidence of AML.

• Environmental Exposure  Ionizing radiation and organic solvents such as benzene and other petroleum products have been associated with a higher risk of developing AML. Both ras mutations and polymorphisms resulting in the inactivation of nicotinamide adenine dinucleotide phosphate, reduced (NADPH)–quinone oxidoreductase have been found in patients with these exposures.

• Prior Therapy  Therapy-related AML typically develops after alkylating agent-induced damage at a median of 5 to 7 years after therapy for the primary malignancy. It is usually associated with an antecedent myelodysplastic disorder. DNA topoisomerase II agents may also produce gene rearrangements leading to AML, with a short latency period of 12 to 18 months following treatment.

• Prior Bone Marrow Disorders  Secondary AML can develop in patients with various hematologic disorders, such as aplastic anemia and severe congenital neutropenia. Other inherited hematologic conditions have also been implicated, such as Bloom's syndrome and Fanconi's anemia. Myelodysplastic and myeloproliferative syndromes, present for at least 3 months, can also progress to AML.

• Age  The incidence of AML increases with age. In the United States, the median age of patients with AML is 68 years. The age-adjusted population incidence is 17.6 per 100,000 for people older than 65 years, compared with 1.8 per 100,000 for those younger than 65 years. Similarly, chromosomal abnormalities occur with greater frequency among this older population of patients.

CLINICAL MANIFESTATIONS • •

The early signs of AML are often vague and non-specific, and may be similar to those of influenza or other common illnesses. Some generalized symptoms include: -fever -fatigue -weight loss or loss of appetite -shortness of breath -anemia -easy bruising or bleeding -petechiae (flat, pin-head sized spots under the skin caused by bleeding) -bone and joint pain -persistent or frequent infections

-enlargement of the spleen may occur but it’s typically mild and asymptomatic -lymph node swelling -sweet’s syndrome (a paraneoplastic inflammation of the skin can occur) -swelling of the gums because of infiltration of leukemic cells into the gum tissue -night sweats -pain or feeling of fullness below the ribs -painless lumps in the neck, underarm, stomach, groin, or other parts of the body. When seen in childhood AML, these lumps, called leukemia cutis, may be blue or purple. -painless lumps that are sometimes around the eyes. These lumps, called chloromas, are sometimes seen in childhood AML and may be blue-green. -an eczema -like skin rash.

TREATMENT • Treatment of AML consists primarily of chemotherapy, and is divided into 2 phases: induction and postremission (or consolidation) therapy. • The goal of induction therapy is to achieve a complete remission by reducing the amount of leukemic cells to an undetectable level. • The goal of consolidation therapy is to eliminate any residual undetectable disease and achieve a cure.

• Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken. • Complete blood count (CBC): A procedure in which a sample of blood is drawn and checked for the following: -The number of red blood cells, white blood cells, and platelets. -The amount of hemoglobin (the protein that carries oxygen) in the red blood cells. -The portion of the sample made up of red blood cells.

Complete blood count (CBC). Blood is collected by inserting a needle into a vein and allowing the blood to flow into a tube. The blood sample is sent to the laboratory and the red blood cells, white blood cells, and platelets are counted. The CBC is used to test for, diagnose, and monitor many different conditions.

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Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it. Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body. Peripheral blood smear: A procedure in which a sample of blood is checked for blast cells, number and kinds of white blood cells, number of platelets, and changes in the shape of the blood cells. Biopsy: The removal of cells or tissues so they can be viewed under a microscope by a pathologist to check for signs of cancer. Biopsies that may be done for childhood AML include the following:

1. Bone marrow aspiration and biopsy: The removal of bone marrow, blood, and a small piece of bone by inserting a hollow needle into the hipbone or breastbone. 2. Tumor biopsy: A biopsy of a chloroma may be done. 3. Lymph node biopsy: The removal of all or part of a lymph node

Bone marrow aspiration and biopsy. After a small area of skin is numbed, a Jamshidi needle (a long, hollow needle) is inserted into the patient’s hip bone. Samples of blood, bone, and bone marrow are removed for examination under a microscope.

• Cytogenetic analysis: A laboratory test in which cells in a sample of blood or bone marrow are viewed under a microscope to look for certain changes in the chromosomes. • Immunophenotyping: A process used to identify cells, based on the types of antigens or markers on the surface of the cell, that may include special staining of the blood and bone marrow cells. This process is used to diagnose the subtype of AML by comparing the cancer cells to normal cells of the immune system. • Lumbar puncture: A procedure used to collect cerebrospinal fluid from the spinal column. This is done by placing a needle into the spinal column. This procedure is also called an LP or spinal tap.

Lumbar puncture. A patient lies in a curled position on a table. After a small area on the lower back is numbed, a spinal needle (a long, thin needle) is inserted into the lower part of the spinal column to remove cerebrospinal fluid (CSF, shown in blue). The fluid may be sent to a laboratory for testing.

NURSING MANAGEMENT • Both registered nurses and licensed practical nurses provide direct care to leukemia patients in general hospitals, homes, or other healthcare facilities. Good supportive nursing care and observation are necessary to: – Prevent or monitor for the infections to which leukemia patients are so susceptible. – Monitor for anemia and bleeding. – Assist in treatments such as chemotherapy, radiation, bonemarrow transplantation, or in giving blood transfusions. – Monitor vital signs. – Provide teaching regarding the prevention of infection, the normal course of leukemia, including the fatigue so many patients feel, the signs and symptoms of anemia, and good dental care (both leukemia and chemotherapy are apt to cause sensitivity in the mouth, vulnerability to infection and bleeding).