acute childhood leukemia

acute childhood leukemia

a progressive, malignant disease of the blood-forming tissues. It is characterized by the uncontrolled proliferation of immature leukocytes and their precursors, particularly in the bone marrow, spleen, and lymph nodes. It is the most frequent cancer in children, with a peak onset occurring between 2 and 5 years of age. Cure rates are high. See also acute lymphocytic leukemia, acute myelocytic leukemia, leukemia.
observations Acute leukemia is classified according to cell type: acute lymphoid leukemia (ALL) includes lymphatic, lymphocytic, lymphoblastic, and lymphoblastoid types; acute nonlymphoid leukemia (ANLL) includes granulocytic, myelocytic, monocytic, myelogenous, monoblastic, and monomyeloblastic types. ALL is predominantly a disease of childhood, whereas acute myeloid leukemia (AML) and ANLL occur in all age groups. The traditional classification of leukemia into chronic and acute types is based on the duration or expected course of the illness and the relative maturity of the leukemic cells. The exact cause of the disease is unknown, although various factors are implicated, including genetic defects, immune deficiency, viruses, and carcinogenic environmental factors, primarily ionizing radiation. Individuals with Down syndrome and other genetic disorders are at increased risk for ALL. In acute leukemia, large immature leukocytes accumulate rapidly and infiltrate other body tissues, especially the reticuloendothelial system, causing decreased production of erythrocytes and platelets. Neutropenia, anemia, increased susceptibility to infection and hemorrhage, and weakening of the bones with a tendency to fracture also occur. Initial symptoms include fever; pallor; fatigue; anorexia; secondary infections (usually of the mouth, throat, or lungs); bone, joint, and abdominal pain; subdermal or submucosal hemorrhage; and enlargement of the spleen, liver, and lymph nodes. The onset may be abrupt or may follow a gradual, progressive course. Involvement of the central nervous system may lead to leukemic meningitis. Characteristically, a peripheral blood smear reveals many immature leukocytes. The diagnosis is confirmed by bone marrow aspiration or biopsy and examination, which in ALL reveal a highly elevated number of lymphoblasts with almost complete absence of erythrocytes, granulocytes, and megakaryocytes. The prognosis is poor in untreated cases, and death occurs usually within 6 months after the onset of symptoms. Survival rates have dramatically increased in recent years with the use of antileukemic agents in combination regimens. Remission of 5 years or longer occurs in 50% to 70% of children with ALL, with 20% to 30% achieving complete remission. Children with AML have a poorer prognosis, and the remission rate is far less than for ALL.
interventions The treatment of acute leukemia consists of a three-stage process involving the use of chemotherapeutic agents and irradiation. In the first phase (remission induction), complete destruction of all leukemic cells is achieved within 4 to 6 weeks with the use of a combination chemotherapy regimen. The drugs used in ALL are the corticosteroids; vinCRIStine sulfate; and L-asparaginase. Allopurinol, a xanthine oxidase inhibitor, or rasburicase is usually administered to inhibit uric acid production and prevent tumor lysis syndrome. Other drugs used in various combination regimens in sequential cycles include methotrexate, mercaptopurine, cyclophosphamide, cytarabine, hydroxyurea, DAUNOrubicin citrate liposomal, and DOXOrubicin hydrochloride. In children with AML the primary drugs for induction remission are 6-thioguanine, daunomycin, cytarabine, 5-azacytidine, vinCRIStine sulfate, and predniSONE. The child is usually hospitalized for part or all of the treatment because of the many side effects of the drugs and the high risk of complications, especially infection and hemorrhage. If severe hemorrhage occurs and does not respond to local treatment, platelet transfusions may be necessary, and in cases of severe anemia, especially during induction therapy, whole blood or packed red blood cells may be needed to raise hemoglobin levels. The second stage of treatment involves prophylactic maintenance to prevent leukemic infiltration of the central nervous system. Because chemotherapy drugs do not cross the blood-brain barrier, therapy usually consists of daily high-dose cranial irradiation for about 2 weeks after induction remission and weekly or twice-weekly doses of intrathecal methotrexate; in some cases, only the drug is given. In small children, irradiation is limited to the cranium to prevent retardation of linear growth, but older children may receive craniospinal radiation. Therapy to maintain remission usually begins after the child is discharged from the hospital and consists of various regimens of drugs in combination. A common schedule includes daily oral doses of mercaptopurine and weekly doses of oral methotrexate, intermittent short-term therapy with predniSONE and vinCRIStine sulfate, and periodic doses of intrathecal methotrexate for prophylaxis against spread to the central nervous system. Complete blood counts are performed weekly or monthly, and bone marrow examinations are performed every 3 to 4 months to detect bone marrow suppression and drug toxicity. Maintenance therapy is discontinued after 2 to 3 years if initial remission is maintained. Continuous treatment beyond 3 years is not advised, as the adverse effects of the medications increase with prolonged use. Relapse occurs in as many as 20% of treated children. If relapse occurs, the child begins the treatment cycle again, usually with predniSONE, vinCRIStine sulfate, and a combination of other drugs not previously tried. With each relapse the prognosis becomes poorer. Other treatments for prolonging remission include immunotherapy using periodic inoculation with bacille Calmette-Guerin vaccine or bone marrow transplantation, which has been successful in inducing long-term remissions in about 10% to 20% of cases, especially those with AML or severe, terminal ALL. Care of the child with acute leukemia involves intensive physical and emotional support during all phases of the disease, its diagnosis, and its treatment. Foremost is the preparation of the child and parents or caregivers for the various diagnostic and therapeutic procedures, including venipuncture, bone marrow aspiration or biopsy, and lumbar puncture. Specific medical and nursing management depends on the particular regimen of drug therapy, although most of the chemotherapeutic agents used in treatment cause bone marrow suppression that may lead to secondary complications of infection, hemorrhage, and anemia. Overwhelming infection is a major problem and one of the most frequent causes of death. Severe neutropenia indicates increased risk of infection. It may occur during immunosuppressive therapy or after prolonged antibiotic therapy. The most common infectious organisms are viruses, especially varicella, herpes zoster, herpes simplex, measles, mumps, rubella, and poliomyelitis; both gram-positive and gram-negative bacteria, including Staphylococcus aureus, S. epidermidis, group A beta-hemolytic streptococci, Pseudomonas aeruginosa, Escherichia coli, Proteus, and Klebsiella; and various parasites and fungi, especially Pneumocystis jiroveci and Candida albicans. To prevent infection, the nurse isolates the child as much as possible, screens visitors for active infection, institutes strict aseptic technique, monitors temperature closely, evaluates possible infection sites (such as needle punctures), encourages adequate nutrition, helps the child to avoid exertion or fatigue, and, at discharge, teaches the child and parents the necessity for avoiding all known sources of infection, primarily the common childhood communicable diseases. Preventive measures for controlling infection also help decrease the tendency toward hemorrhage. Special attention is given to skin care, oral hygiene, cleanliness of the perineal area, and restriction of activities that could result in unintentional injury. A major nursing consideration is the management of the many side effects resulting from drug toxicity, including nausea and vomiting, anorexia, oral and rectal ulceration, alopecia, hemorrhagic cystitis, and peripheral neuropathy, including weakness and numbing of the extremities and severe jaw pain. Although corticosteroid treatment usually increases the appetite and produces a euphoric sense of well-being in the child, it also causes moon face, which is reversed with cessation of steroid therapy. During maintenance therapy, the nurse continues to provide emotional support and guidance, specifically teaching parents which side effects are normal reactions to drugs and which indicate toxicity and require medical attention. In terminal stages of the disease, relief of discomfort and pain becomes the primary focus. Effective measures include careful physical handling of the child, frequent position changes, prevention of pressure on painful areas, and control of annoying environmental factors, such as excessive light and noise. Nonsalicylate analgesics are used as needed, depending on the severity of pain. Opioids are used to handle end-of-life pain. Referrals can be made to palliative care teams for symptom management and ongoing family support.
References in periodicals archive ?
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Most environmental risk factors have been found to be weakly and inconsistently associated with either form of acute childhood leukemia.
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