Objective:To analyze the composition and clinical characteristics of urinary calculi in infants in Xinjiang.Methods:The clinical data of 75 infants with urinary calculi admitted to the People′s Hospital of Xinjiang Uygur Autonomous Region from January 2016 to December 2021 were retrospectively analyzed, including the general situation of the children, stone-related parameters, random urine pH value, urine culture and biochemical examination results. The serum uric acid, serum calcium, urine pH value, positive rate of urine culture, and stone length between infants with and without ammonium urate stones were compared. Measurement data conforming to normal distribution were expressed as mean ± standard deviation ( ± s), and independent sample t-test was used for inter-group comparison. Measurement data that did not conform to the normal distribution were expressed as the median (interquartile distance) [ M ( Q1, Q3)], and Mann-Whitney U test was used for comparison between groups. The Chi-square test, continuity-corrected Chi-square test or Fisher exact probability method were used for the comparison of count data. Results:The median age of infants with urinary calculi was 23.04 months, and the ratio of male to female was 3.2∶1. More than half of the infants (81.3%, 61/75) came from rural areas, 57.3% (43/75) were malnourished, 33.3% (25/75) were complicated with urinary tract infection, and 8.0% (6/75) were combined with urinary system congenital malformation. The calculi were found in 53 cases (70.67%) of kidney, 27 cases (36.0%) of ureter, 17 cases (22.67%) of urethra and 16 cases (21.33%) of bladder. The analysis of calculi composition showed that there were 44 cases (58.67%) of ammonium urate, 39 cases (52.0%) of calcium oxalate, 14 cases (18.67%) of apatite carbonate and 7 cases (9.33%) of uric acid. Kidney calculi was more common in female infants ( P=0.011). Compared with the infant group ( n=19), calcium oxalate stones were more common in the preschooler group ( n=56) ( P=0.039), but there were not statistical difference in the incidence of ammonium urate, apatite carbonate and uric acid stones. There were not statistical difference in gender, age, place of residence, nutritional status, serum uric acid, serum calcium, urine pH value, positive rate of urine culture, stone maximum diameter and incidence of bladder stones between ammonium urate group and non-ammonium urate group. Conclusions:The incidence of urinary calculi in infants is higher in boys, and the most common site of calculi is the upper urinary tract, especially in female kidney calculi. Ammonium urate is the main component of urinary calculi in infants. Calcium oxalate stones are more common in preschooler group. Infants with urinary calculi are mostly rural residents, and malnutrition and urinary tract infection are more common.

【Objective】 To analyze the clinical characteristics of children with ammonium urate stones in Xinjiang, so as to provide reference for the prevention and treatment of this disease. 【Methods】 The clinical data of all children with ammonium urate stones admitted to the People’s Hospital of Xinjiang Uygur Autonomous Region from 2016 to 2021 were retrospectively analyzed, including age, sex, body mass index, stone site, stone size, stone component, urine pH, urine culture and biochemical examination results. The serum total protein, albumin, sodium, potassium, calcium, magnesium, uric acid and urine pH were compared between the pure and mixed groups. 【Results】 A total of 61 children (31.6%) had ammonium urate stones, their average age was (4.05±3.37) years, and the male to female ratio was 2.21∶1. Among them, there were 37 cases (60.7%) of renal calculi and 50 cases (82.0%) of upper urinary calculi. The most common component of mixed ammonium urate stones was calcium oxalate, including calcium oxalate monohydrate, calcium oxalate monohydrate and calcium oxalate dihydrate. Compared with mixed type, children with pure stone type had a younger age (P=0.001) and a smaller stone size (P=0.003). Positive urine culture was detected in 14 cases (23.0%), 7 of which (50% were infected with Escherichia coli, and 11 (78.6%) with non-urease bacteria. 【Conclusion】 Non-urease bacteria are the main pathogens of urinary tract infection in children with ammonium urate stones. The incidence is higher in boys, and the most common stone location is upper urinary tract. Calcium oxalate is the most common mixed component. Pure type is more common in young children and the stones are relatively small.