Tumor lysis syndrome is a frequent complication (12%-16%) of Burkitt's lymphoma.4 Onset can occur prior to treatment or as a sequela of chemotherapy initiation. Rapidly proliferating tumor cells die naturally because they outgrow their supply of nutrients, but chemotherapy also causes massive cell death in rapidly growing cells. Tumor lysis syndrome is a life-threatening condition that can lead to renal failure and cardiac arrhythmias. As the cells die, intracellular metabolites (nucleic acids, potassium, and phosphates) are released into the bloodstream. Nucleic acids are converted to uric acid in the liver, and uric acid can form crystals that obstruct the kidney. Phosphate binds calcium, forming calcium phosphate salts that also can clog renal tubules and lead to renal insufficiency. Renal failure can require dialysis and may lead to death. Secondary hypocalcemia may result, leading to neuromuscular irritability and tetany. Hyperkalemia can cause arrhythmias, such as peaked T waves and prolonged PR interval, and lead to ventricular tachycardia or fibrillation.
Chemotherapy is the gold standard of treatment for Burkitt's lymphoma, but it can induce tumor lysis syndrome in the first 24 hours of treatment if the patient's tumor burden is high. Maintaining urine output is essential to promote excretion of the intracellular metabolites. Aggressive hydration is given prior to and during initiation of chemotherapy. Allopurinol is given empirically to prevent hyperuricemia prior to initiation of chemotherapy. Rasburicase, a urate oxidase that is faster-acting than allopurinol, is used in urgent treatment of tumor lysis syndrome. In this patient, allopurinol was started at the onset of treatment but was replaced with rasburicase when tumor lysis syndrome developed after the start of chemotherapy.
Short courses of intensive multi-agent chemotherapy are the standard of care. Treatment regimens include intrathecal therapy to prevent or treat CNS disease. Neurotoxicity, mucositis, cardiac insufficiency, and infertility are side effects of some of these chemotherapeutic agents. A recent international clinical trial demonstrated that doses of cyclophosphamide and doxorubicin could be reduced without altering efficacy and survival in intermediate-risk NHL.2 Newer agents, such as rituximab, a monoclonal antibody that targets the CD20 antigen found in high levels on Burkitt's lymphoma cells, may prove to be effective adjuvant therapies with minimal side effects.5
Conclusion Burkitt's lymphoma is a rare childhood tumor with a doubling time of 24 hours. When this toddler presented with abdominal distention and a palpable mass, a pediatric surgeon was consulted for open tissue biopsy and central venous access. At the time of operation, the mass had already caused bowel perforation, a common complication of Burkitt's lymphoma. Following complete resection with a temporary ileostomy and early initiation of aggressive chemotherapy, the tumor responded rapidly. Treatment was complicated by tumor lysis syndrome, which was successfully managed in an ICU at a pediatric cancer center. Primary care clinicians must be aware of the urgency of diagnosis and treatment required when Burkitt's lymphoma is suspected. JAAPA
Holly Green works in pediatric surgical oncology, Michael Rytting is an associate professor of pediatrics, and Charles Cox is a professor of surgical oncology, all at Children's Cancer Hospital, University of Texas M.D. Anderson Cancer Center, Houston, Texas. Dr. Cox is also a professor of pediatric surgery at the University of Texas Medical School, Houston. The authors have indicated no relationships to disclose relating to the content of this article.
DRUGS MENTIONED
Allopurinol (Aloprim, generics)
Cyclophosphamide (Cytoxan)
Cytarabine (Cytosar-U, DepoCyt, generics)
Doxorubicin (Adriamycin, generics)
Furosemide (Lasix, generics)
Methotrexate (Trexall, generics)
Prednisone (Prednisone Intensol, generics)
Rasburicase (Elitek)
Rituximab (Rituxan)
Vincristine (Oncovin)
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