Mechanism by which shock wave lithotripsy can promote formation of human calcium phosphate stones

Andrew P. Evan, Fredric L. Coe, Bret A. Connors, Rajash K. Handa, James E. Lingeman, Elaine M. Worcester

Research output: Contribution to journalArticle

9 Scopus citations


Human stone calcium phosphate (CaP) content correlates with higher urine CaP supersaturation (SS) and urine pH as well as with the number of shock wave lithotripsy (SWL) treatments. SWL does damage medullary collecting ducts and vasa recta, sites for urine pH regulation. We tested the hypothesis that SWL raises urine pH and therefore Cap SS, resulting in CaP nucleation and tubular plugging. The left kidney (T) of nine farm pigs was treated with SWL, and metabolic studies were performed using bilateral ureteral catheters for up to 70 days post-SWL. Some animals were given an NH<inf>4</inf>Cl load to sort out effects on urine pH of CD injury vs. increased HCO<sup>-</sup><inf>3</inf> delivery. Histopathological studies were performed at the end of the functional studies. The mean pH of the T kidneys exceeded that of the control (C) kidneys by 0.18 units in 14 experiments on 9 pigs. Increased HCO<sup>-</sup><inf>3</inf> delivery to CD is at least partly responsible for the pH difference because NH<inf>4</inf>Cl acidosis abolished it. The T kidneys excreted more Na, K, HCO<sup>-</sup><inf>3</inf>, water, Ca, Mg, and Cl than C kidneys. A single nephron site that could produce losses of all of these is the thick ascending limb. Extensive injury was noted in medullary thick ascending limbs and collecting ducts. Linear bands showing nephron loss and fibrosis were found in the cortex and extended into the medulla. Thus SWL produces tubule cell injury easily observed histopathologically that leads to functional disturbances across a wide range of electrolyte metabolism including higher than control urine pH.

Original languageEnglish (US)
Pages (from-to)F938-F949
JournalAmerican Journal of Physiology - Renal Physiology
Issue number8
StatePublished - 2015


  • Histopathology
  • PH regulation
  • Renal function
  • Thick ascending limb

ASJC Scopus subject areas

  • Physiology
  • Urology

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