[Urinary glycosaminoglycans after extracorporeal shock wave lithotripsy in patients with kidney lithiasis]

Extracorporeal shock wave lithotripsy (ESWL) is a technique that is not free of adverse effects. Renal changes detected during complementary exploratory procedures have been described, although these are minimal, resolve within a few days, do not present clinical manifestations and are not detected on ultrasound in most of the cases. For this reason, we studied a marker for renal injury, the urinary excretion of glycosaminoglycans (GAG) in patients with renal calculi, before, immediately after and 30 days following ESWL. The novelty of the study lies in that we have classified the patients with calculi according to the degree of renal function before ESWL, since it is recognized that the obstructive features of lithiasis can cause some degree of renal impairment.

Urinary GAG was quantified according to the colorimetric method described by Pennock.

Urinary GAG levels were found to be lower in patients with renal calculi and preserved renal function than in healthy control subjects. In the presence of renal failure, these levels are elevated due to the obstructive nephropathy caused by calculi. Urinary GAG significantly increased post-ESWL in patients with renal lithiasis and preserved renal function or renal failure. At 30 days post-ESWL, GAG returned to pre-test levels.

Quantification of urinary GAG is a useful biochemical method in the evaluation of renal parenchymal injury produced by ESWL.