Role of serum sodium in assessing hospital mortality in cancer patients with spontaneous tumour lysis syndrome inducing acute uric acid nephropathy

Spontaneous tumour lysis syndrome (STLS) inducing acute uric acid nephropathy, a rare and neglected disease, presents more insidiously than conventional post-treatment tumour lysis syndrome. Although STLS is a serious and potentially fatal complication in patients with neoplastic disorders, few investigations have addressed the relevance of clinical and laboratory features in assessing prognosis. A retrospective study was conducted, reviewing the records of all patients who developed acute renal failure (ARF) at Chang Gung memorial hospital between 1 July 1999 and 30 June 2003. STLS-induced acute uric acid nephropathy was identified in 12 of 1072 ARF patients (1.1%) during the study period. All patients had advanced stage tumours with large tumour burden, and 66.7% of cases had abdominal organ involvement. All 12 hyperuricemic patients became oliguric despite conservative therapy, and remained hyperuricemic (21.6 ± 5.2 mg/dl) before dialysis therapy. Diuresis developed in eight patients (66.7%), with associated resolution of hyperuricemia, azotemia and metabolic derangements following dialysis initiation. Overall hospital mortality was 58.3%. Death in most patients was related to hyponatremia and hypoalbuminemia on admission. The serum sodium was found to have the best Youden index (0.86) and highest overall prediction accuracy (93%). Moreover, serum sodium and serum albumin for individual patients were significantly and positively correlated (r = 0.617, p = 0.032). This investigation confirms a grave prognosis for cancer patients with STLS inducing acute uric acid nephropathy. Hyponatremia and hypoalbuminemia on the first day of admission indicate poor prognosis in such patients.