Selective Elevation of Urinary Enzyme Levels after Extracorporeal Shock Wave Lithotripsy

Abstract

Urinary enzyme testing has been used by many investigators to diagnose and monitor various types of renal injury. Three urinary enzymes, N-acetyl-beta-glucosaminidase, beta-galactosidase and gamma-glutamyl transferase were monitored in 17 patients before and after a single, unilateral extracorporeal shock wave lithotripsy treatment. Stones were in the renal pelvis or calices except for 1 treated in situ in the proximal ureter. Urine specimens were collected before extracorporeal shock wave lithotripsy and at 1, 3, 5, 7, 10, 14, 21 and 28 days after treatment. N-acetyl-beta-glucosaminidase and beta-galactosidase levels increased significantly after treatment (p less than 0.05). Gamma-glutamyl transferase levels increased after treatment but this was not statistically significant. All enzyme levels were highest on days 1 and 3 after lithotripsy and returned to baseline by day 28. Factors associated with post-treatment enzyme elevation included female sex, a lower pre-treatment creatinine clearance and stone size greater than 1 cm. These findings indicate that there is a transient selective increase in urinary enzyme excretion after extracorporeal shock wave lithotripsy.