Diagnosis of renal stones with underlying metabolic abnormalities using FTIR spectroscopy

Abstract

. The importance of FourierTransform Infra Red (FTIR) spectroscopic stoneanalysis of the kidney stone in guiding the work up ofchildren with underlying metabolic disorders isemphasized in this brief communication.Between 2005 –2007, there were eleven patients whopresented with renal and upper urinary tract stonedisease (kidney, ureters) with the principal author. Thestag horn stones and the multiple stones in kidneyswere subject to open surgery after a biochemicalmetabolic work up. The stones that were removed aftersurgery were sent for analysis by FTIR spectroscopy.Other biochemical tests were done after FTIRspectroscopy gave a clue to the nature of the stones.Three children with metabolic stones were diagnosed.One child had multiple pure uric acid stones producingacute renal shut down and another had multiple purecystine stones with associated Pelvi-ureteric junctionobstruction which presented severe hypertension. Thethird child had xanthine stones. The FTIR spectroscopypicture of the cystine stones is shown in Fig. 1. Fourpatients who were having small stones in the kidney areasymtomatic and they are under careful follow up Theircalcium and creatinine spot tests were normal. Thediagnosis of metabolic stones was facilitated in thethree children by FTIR spectroscopic analysis of thestone. The child with cystine stones presented withrecurrent stones on the left kidney due to noncompliance to treatment after starting therapy. Thechild with uric acid stones is currently on urinaryalkalinisation and allopurinol therapy and has normalbiochemical renal functions. The child with xanthinestones is on high oral fluid regime.The reports of diagnosis of metabolic renal stones inchildhood in India have been scanty. A large study byAhlawat