Short-term changes in renal function after extracorporeal shock wave lithotripsy in children

To our knowledge despite numerous studies the biological effect of extracorporeal shock wave lithotripsy (ESWL, Dornier Medical Systems, Inc., Marietta, Georgia) on the function of the immature kidney has not yet been evaluated. We determined the short-term effect of ESWL on renal function in children.

In a 5-year period 65 children were treated for 77 kidney stones by ESWL and followed regularly at our department. In 16 children the short-term effect of shock wave energy was studied by measuring blood parameters (sodium, potassium, urea, creatinine and C-reactive protein), urinary electrolytes (sodium, potassium and creatinine), urinary enzyme activity (aspartate transaminase, alanine transferase, alkaline phosphatase and lactate dehydrogenase) and the excretion of beta 2-microglobulin. Samples were obtained immediately before and 2 hours after ESWL, and on days 1, 2, 8, 15, 30 and 90 after treatment.

Morphological changes in the kidneys were not detected by ultrasound during followup. No significant changes were noted in overall renal function, serum parameters or urine electrolytes. A significant elevation in the excretion of aspartate transaminase, alkaline phosphatase, lactate dehydrogenase and beta 2-microglobulin was observed, indicating proximal tubular dysfunction and cell destruction. Enzyme levels returned to baseline within 15 days.

Our results demonstrate that shock wave energy induces transient functional damage of tubular function in children. Minimizing the kV. and number of shocks may decrease the deleterious effect. When considering functional regeneration time, the minimal interval between 2 shock wave treatments should be at least 15 days. The long-term effect needs further investigation.