URINARY LEAKAGE OF TUBULAR ENZYMES AFTER SHOCK-WAVE LITHOTRIPSY

Objectives: Urinary loss of tubular marker enzymes following shock wav e lithotripsy (SWL) suggests corresponding morphological changes in th e kidney. To date, the morphological correlate of enzymuria and its de pendence on the energy applied remains unclear. Methods: In an animal study, the acute morphological changes occurring in the tubulus cells as the basis of enzymuria were investigated. It was evaluated whether SWL-induced enzymuria correlates with the extent of renal damage. Resu lts: Acute morphological changes in the tubulus cells were demonstrate d beneath isolated tubulus necrosis. The mechanically induced lesions of the cell organelles included fragmentation of the lysosomes and sev ere alterations of the cell membrane. The tubulus damage can be quanti fied. With the help of histochemical N-acetyl-beta-D-glucosaminidase ( NAG) staining and electron microscopic observations, a significant cor relation was found between the shock wave parameters number of impulse s and intensity and the tubular damage. The intensity of NAG enzymuria reflected the severity of the tubular damage. Conclusions: In this an imal model, NAG proved to be a suitable marker enzyme for estimation o f the degree of SWL-induced tubular damage.