Chemical Composition Of Stones In Paediatric Urolithiasis

Chemical composition of stones is one of the important diagnostic criteria for aetiology of stone formation and treatment to prevent recurrence. This paper reports composition of stones in children at a tertiary hospital by Fourier Transformation Infrared Spectroscopy (FTIR).

Between January-June 2015, 412 urinary stones from children were analysed by FTIR. Chi-square tests were used for the comparison of categorical measurements between groups. All reported values were 2-sided and statistical significance was considered at p-value ≤0.05.

Of the 412 stones, 263 (63.8%) were renal, 101(24.5%) bladder and 48 (11.7%) ureteric. The mean age of children was 7.15±4.13 years with a M:F ratio 2.4:1. Of the 412 stones, 144(34.9%) were pure stones composed of one compound and 268(65.1%) were mixtures. Frequency of compound in stones was Ammonium Acid Urate (AAU) (65%), Calcium Oxalate (CaOx) (76.9%), Uric Acid (5%), Calcium Phosphate Apatite (7%), Whitlockite (8.4%), Struvite (4%), Cystine (0.72%) and Xanthine (2.11%). Frequency of compounds analysed in three ages groups 0-5, 6-10 and 11-15 years showed high frequency of AAU (73%) in 0-5 years as compared to (60%) in 11-15 years (p<0.018). CaOx (90%) in 11-15 as compared to (62.5%) in 0-5 years (p<0.001). Bladder stones were more prevalent in children 0-5 years (32%) vs 19% in 11-15 years (p<0.004) while renal were 75% in 11-15 years and 54% in 0-5 years (p<0.04).

AAU stones known to be associated with malnutrition and chronic diarrhoea are highly prevalent in paediatric stones formers in our population in the kidney, bladder and ureter.