Leukemia acute lymphocytic

Mercaptopurine (6-MP) is an oral purine analog that is converted to a ribonucleotide to inhibit purine synthesis. Mercaptopurine is converted into thiopurine nucleotides, which are catabolized by thiopurine S-methyltransferase (TPMT), which is subject to genetic polymorphisms and may cause severe myelosuppression. TPMT status may be assessed prior to therapy to reduce drug-induced morbidity and the costs of hospitalizations for neutropenic events. Mercaptopurine is poorly absorbed, with a time to peak concentration of 1 to 2 hours after an oral dose. The half-life is 21 minutes in pediatric patients and 47 minutes in adults. Mercaptopurine is used in the treatment of acute lymphocytic leukemia and chronic myelogenous leukemia. Significant side effects include myelosuppression, mild nausea, skin rash, and cholestasis. When allopurinol is used in combination with 6-MP, the dose of 6-MP must be reduced by 66% to 75% of the usual dose because allopurinol blocks the metabolism of 6-MP. 

Teniposide, a topoisomerase II inhibitor, is administered as an infusion over 30 to 60 minutes to prevent hypotension. The pharmacokinetics are described by a three-compartment model, with an a half-life of 0.75 hours, a (5 half-life of 4 hours, and a terminal half-life of 20 hours. Considerable variability in clearance of teniposide in children has been reported.17 Teniposide has shown activity in the treatment of acute lymphocytic leukemia, neuroblastoma, and non-Hodgkin s lymphoma. Side effects include myelosuppression, nausea, vomiting, mucositis, and venous irritation. Hypersensitivity reactions may be life-threatening. 

Compare the classification systems for acute lymphocytic leukemia (ALL) and acute nonlymphocytic leukemia (ANLL). 

Acute leukemias are classified according to their cell of origin. Acute lymphocytic leukemia (ALL) arises from the lymphoid line. Acute nonlymphocytic leukemia (ANLL) or acute myelogenous leukemia (AML) arises from the myeloid line. 

Children with acute lymphocytic leukemia (ALL) are classified according to their risk of relapse. Risk assessment is an important factor in the selection of treatment. The goal is to match treatment to risk and minimize over- or undertreatment. 

The current induction therapy for acute lymphocytic leukemia (ALL) typically consists of vincristine, asparaginase, and a steroid (prednisone or dexamethasone). An anthracycline is added for higher-risk patients. 

Because the risk of central nervous system (CNS) involvement is high, regardless of cerebrospinal fluid (CSF) cytology all patients with acute lymphocytic leukemia (ALL) receive intrathecal prophylaxis. 

What information is suggestive of acute lymphocytic leukemia ... 

For all newly diagnosed patients with leukemia, an aspirate of the liquid marrow and a bone marrow core biopsy are obtained.5 Morphologic and cytochemical analysis of these samples distinguishes three subtypes of ALL (LI, L2, and L3) and eight subtypes of AML (M0-M7) as classified by the French-American-British (FAB) scheme. See Tables 92-2 and 92-3 for the FAB classification of acute myelogenous leukemia and acute lymphocytic leukemia. 

TABLE 92-3. Morphologic (FAB) Classification and Immunophenotype of Acute Lymphocytic Leukemia... 

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