Impact of percutaneous renal stone removal on renal function: assessment by urinary lysozyme activity.

Lysozyme in the urine in concentrations greater than 3 micrograms per milligram of creatinine reflects renal tubular disease or dysfunction in patients without bowel disease or leukemia. We therefore used urine lysozyme assays to assess renal response to percutaneous nephrostomy and stone removal in 42 patients. Eight patients had striking increases (4.2-21.1 [mean 7.58] micrograms/mg creatinine) immediately after nephrostomy puncture in urine obtained directly from the punctured kidney. Lysozyme declined sharply thereafter and was within normal limits in all cases by postoperative day 3. This increase appeared to result from bleeding into the urine from the tract. Five other patients had lysozymuria on admission, only 1 of whom had a sharp increase after nephrostomy puncture. In the remaining patients, the lysozyme levels remained within normal limits throughout the hospital course. These data are further evidence of the absence of significant deleterious effects of nephrostomy puncture on the kidney.