Neglected cause of renal failure in cancer patients: Spontaneous tumor lysis syndrome inducing acute uric acid nephropathy

Background. Acute spontaneous tumor lysis syndrome (STLS) presenting with hyperuricemic acute renal failure (ARF) is a rare disease that is probably overlooked in patients with neoplastic disorders. This study attempted to define the incidence, clinical characteristics, therapeutic approaches, and prognosis of this entity. Methods. A retrospective study was conducted, reviewing the records of all patients who developed ARF at Chang Gung Memorial Hospital between July 1, 1999, and June 30, 2003. Results. STLS-induced acute uric acid nephropathy was identified in 12 of 1,072 ARF patients (1.1%) during the study period. Most presentations were non-specific or related to the symptoms of malignancy. All patients had advanced-stage tumors with large tumor burden, and abdominal organs were involved in 66. 7% of cases. All 12 hyperuricemic patients became oliguric despite conservative therapy, and were still hyperuricemic (21.6 ± 5.2 mg/dl) before dialysis therapy. Diuresis developed in 8 patients (66. 7%), with associated resolution of hyperuricemia, azotemia, and metabolic derangements after dialysis initiation. The patients who developed diuresis had mean serum uric acid levels of 9.8 ± 3.3 mg/dl, and median levels of 10.3 mg/dl. Four patients (33.3%) survived, with 2 suffering residual renal function impairment. Conclusion. Acute STLS presenting with hyperuricemic ARF is rare and is easily overlooked as a cause of acute uric acid nephropathy in patients with bulky or occult neoplastic disorders. In contrast to hyperuricemia and oliguria, which are constant findings, azotemia or impaired renal function is not always present on initial presentation. Despite poor outcomes in patients with STLS developing acute uric acid nephropathy, early recognition, aggressive management, and prompt dialysis are mandatory.