Urolithiasis in Tunisian children: a study of 120 cases based on stone composition

The composition of urinary stones in children depends on socioeconomic cond itions and hygiene, geographical area, and dietary habits. We analyzed urin ary stones from 120 consecutive Tunisian children (81 males, 39 females) ag ed 5 months to 15 years. The stone was located in the upper urinary tract i n 91 cases (76%). Stone analysis included both a morphological examination and an infrared analysis of the nucleus and the inner and peripheral layers . The main components of bladder calculi were whewellite (69%) and struvite (22%), whereas the main component of upper urinary tract calculi was whewe llite (67%). The nucleus of bladder stones was composed of ammonium urate ( 45%), struvite (28%), cystine (10%), and carbapatite (7%), The nucleus of k idney and ureteral calculi was mainly composed of ammonium urate (38%), whe wellite (24%), carbapatite (13%), or struvite (11%). Based on stone composi tion, urinary tract infection was involved in the nucleation or growth of a third of calculi. Endemic urolithiasis involving simultaneous nutritional, metabolic, and infectious factors, and defined by its nucleus composed of ammonium urate without struvite, represented 40% of cases. Exclusive metabo lic factors - including genetic diseases such as primary hyperoxaluria, cys tinuria, and hypercalciuria - were responsible for less than 25% of cases.