CHEMICAL COMPOSITION OF RENAL STONES AND ASSOCIATED RISK FACTORS IN CHILDREN UNDER 15 YEARS OF AGE

ABSTRACT       

Background: Stones of the urinary tract are common in Asian countries .Knowing their composition in children can help in the prevention and early management of urolithiasis and thus improve the quality of life.

Aims: To determine frequency of renal stones in children less than 15 years of age.

Setting and duration of study: Over two years, all pediatric renal stone samples were taken from tertiary care hospitals of Peshawar Khyber Pakhtunkhwa Province and they were analyzed for chemical composition at PMRC Research Centre Khyber Medical College Peshawar. 

Methods: This descriptive study was based on convenient sampling after an informed consent was taken from the child’s caregiver .A questionnaire comprising of demographic, dietary, clinical history and family history was administered to the patient or proxy  and stone samples were collected  for  chemical analysis using urinary calculi analysis kit. Data was analyzed using SPSS version 16.0 

Results: A total of 145 patients were included in the study comprising 86(59%) males and 59(41%) females .Stones were more common in males  (M/F ration 1.5:1). Mean age was 7.37+ 4.1 years. About 44(30%) children were below 05 years of age, 53 (36.5%) were between 05-09 years and 48(33%) were over 10 years of age. 

Family history of urinary stones was present in 64(44.57%) children, with maternal family history in 21(14.5%) cases, paternal in 38(26.2%) cases and both maternal and paternal in 05(3.4%) children^. 

Majority 47(32.4%) of renal stones were heterogeneous in composition, consisting of calcium oxalate, calcium phosphate and ammonium urate.  Pure calcium oxalate stones were seen in 38(26.2%) samples, while a combination of calcium oxalate and calcium phosphate was present in 31(21.4%) stones. Ammonium urate in combination with calcium oxalate was seen in 19 (13.1%) and uric acid with calcium oxalate and calcium phosphate was seen in only 06 (4.1%) stones.  

Calcium oxalate was the principal constituent of stones and it was present in 143(98%) pediatric stone samples along with calcium phosphate, ammonium urate, struvite (magnesium ammonium phosphate) and uric acid. Calcium phosphate was the second constituent present in 85(58.6%) stones. Ammonium urate was present in 66(45.5%) stones and uric acid in only 6(4.13%) stones. Two (1.37 %) stones were infectious consisting of struvite. One stone each (0.7 %) was of pure cystine and xanthene.  

Conclusion: Majority of renal stones in pediatric age have a  mixed composition and most patients belong to poor socioeconomic group  with very strong family history of calculus disease .Stone analysis is  helpful for physicians to manage this disease at early age.