Proximal renal tubular dysfunction in severe burns.

Proximal renal tubular function was studied in 11 patients with severe burn injury. Creatinine clearance was normal or increased in ten patients. Fractional excretion of sodium was less than 1% in ten. Fractional excretion of uric acid and amylase were increased in all but four and two cases, respectively, while absolute clearances of lysozyme and beta 2-microglobulin were increased in all but one patient. Renal threshold phosphate concentration was reduced in four patients. Twenty-four-hour urine glucose excretion exceeded 1 g in five patients, aminoaciduria was noted in eight, and proteinuria, predominantly globulinuria, was present consistently. Metabolic acidosis was seen in one patient, and transient hypokalemia occurred in two. Abnormalities of proximal tubular function were more marked in the five patients with the greatest extent of third-degree burns who died. The cause of proximal tubular dysfunction is not clear and may be related to an adaptive response to severe injury.