Tumor lysis syndrome (TLS) is an oncologic emergency that is caused by massive tumor cell lysis after initiation of cytotoxic therapy in patients with a large tumor burden, high cancer cell proliferation rate and chemosensitivity. Incidence of TLS is highest in patients with leukemia, lymphoma, multiple myeloma, esophageal cancer and hepatocellular carcinoma. Clinical manifestations include nausea, vomiting, diarrhea, anorexia, lethargy, seizures, muscle cramps, tetany, hematuria, acute renal failure, cardiac arhythmias, heart failure, syncope, and sudden death.
Symptoms are due to the release of large amounts of potassium, phosphate, and nucleic acids into the circulation. Catabolism of nucleic acid produces hyperuricemia, increased uric acid excretion and precipitation of uric acid in renal tubules, resulting in acute kidney injury. Hyperphosphatemia exacerbates acute kidney injury due to deposition of calcium phosphate in renal tubules.
Laboratory TLS is defined as any two or more of the following metabolic abnormalities occurring within seven days after initiating chemotherapy:
- Uric acid 8 mg/dL or higher
- Potassium 6 mEq/L or higher
- Phosphorus 6.5 or higher for children or 4.5 mg/dL or higher for adults
- Calcium 7.0 mg/dL or less
Clinical TLS is defined as laboratory TLS plus one or more of the following: serum creatinine increased 1.5 times the upper limit or more, cardiac arrhythmia, seizure or sudden death.