Early markers of renal injury in predicting outcome in thermal burn patients.

Acute renal failure (ARF) is a well known complication of severe burn and is an important factor that can increase mortality. To determine the predictors of acute renal failure that occur in major burns, we studied 40 patients with moderate to severe thermal burn injury - second to third degree with > 20% of total body surface area. All patients were subjected to routine investigations including: Serum creatinine, blood urea nitrogen, fractional excretion of sodium, urinary malondialdehyde and microalbuminuria on day 0, 3, 7, 14 and 21 of hospitalization. Nine patients (22.5 %) developed acute renal failure; 4 patients required supportive dialysis. The group that developed ARF showed an increase of markers of glomerular damage with appearance of micro-albuminuria on day 0 that reached 3 - 4 folds above its normal level on day 14 and remained constant with elevated serum creatinine and burn size in the 3 rd week of ARF, and progressed to overt proteinuria in 3 cases. Urinary malondialdehyde increased 3 folds above normal values before developing acute renal failure, and gradually increased on day 14, which coincided with the increased of microalbuminuria. Two cases (22.2%) in the ARF group who developed septicemia and required dialysis died on the 32 nd and 36 th days post-burn. Burn size and occurrence of septicemia were the only predictors of acute renal failure using multiple regression analysis (P value < 0.001 and < 0.0371, respectively). We conclude that acute renal failure complicates burn patients and is related to the size and depth of burn and occurrence of septicemia. Microalbuminuria and urinary malondialdehyde are useful markers for prediction of renal outcome in such group of patients.