Metabolic Constituents of Urinary Stone Composition in Sudanese Children

Objectives: The aim of this study was to show the biological ch aracteristics of pediatric urolithiasis in Sudanese patient’s popula tion and evaluation of some metabolic risk factors. Materials and Methods: We analyzed prospectively urinary stones from 175 consecutive children (129 males, 46 females), aged 3 months to 16 years. Patients were reviewed in Soba Teaching Hospital, Khartoum s tate Sudan, during the period October 2005-May 2009. The chemical analysis of sto nes was carried out by Urinary Calculi Analysis Kit, manufacturer DiaSys Diagnosti c system GmbH. One hundred and thirty blood samples (80 patients, 50 controls) were collected from patients with renal stone to screen some metab olic risk factors, serum calcium, serum phosphate, serum uric acid, and serum creatin ine. Fifty samples, of 24 hours urine collection (30 patients, 20 controls) were co llected to determine the excretion of urine calcium, phosphate and uric acid. It was ana lyzed by auto analyzer Cobas Integra 400 Plus. Statistical Analysis: Statistical analysis of data was carried out using oftware SPSS 11.0 for Windows. Statistical significance was determined using chi-square test & Fisher exact test. Results: The sex ratio was 2.8:1 boys to girls Clinical pr esentation of this pathology was dominated by flank pain (67%), urinar y t act infection (49%) hematuria (27%), and acute renal failure (6.2%). St ones were located in the upper urinary tract in 74.9% of cases. Calcium Oxalate wa s found more frequently in children stones than infants (P < 0.0001) and was t he main component in 55.4% of stones constituents. Cystine stone was more frequen t in infant than children (P < 0.011). Uric acid stones were more frequent among b oy’s stones than girls’ (8% vs 0.6%) (P<0.05). Metabolic urolithiasis cases accounted for 6.3% of our patients, and earlier onset of symptoms, were more common in patients wit h positive family history of urolithiasis, increased frequency multiple and bila ter l stones were observed in this group compared with the other etiologic groups. The re was increase urinary calcium, uric acid excretion in patients with renal stones ( p>0.009, p> 0.013 respectively). Conclusions: urolithiasis is a serious problem among Sudanese children with early onset of presentation. Proper management of UTI wit h a careful metabolic assessment of young stone formers is valuable in combating uro lithiasis. INTRODUCTION The composition and clinical characteristics of urinary calculi in children vary greatly from one part of the world to another and from one historic period to the next(Oner et al. 1997). This variation is related to climate, dietary, genetic, and socioeconomic factors (Kamoun et al. 1999). Urolithiasis (UL) can develop in pediatric patients as a result of metabolic disorders, anatomical malformations of the urinary tract, infection, and environmental and nutritional factors (Gearhart e al. 1991). Elfadil. Gh. A et al. 22 Urolithiasis in children is a frequent disease characterized by its varied patho physiological background (Angwafo, III et al. 2000) Clinical investigations of a patient with urolithiasis include a careful history, radiological and biochemical evaluation. It is always important to define the cause of urinary calculi disease among children to prevent recurrence and possible impairing of renal function. (Kamoun et al. 1997). A numbers of publications have previously reported the high prevalence and particular patterns of stone disease among children in developing countries (Elder JS 2004). We lack data about Urolithiasis in Sudanese children. MATERIALS AND METHODS Between October 2005 to May 2009, 175 pediatric patients with Urolithiasis, their age between 3 months16 years, in the pediatric Surgery Clinic, Soba Teaching Hospital in Khartoum state. Patients were referred from different regions of Sudan State. Full documentation included recording of age, sex, residency, age of onset of symptoms, age of diagnosis of stone disease, clinical presentation, past medical and surgical history, family history of stone disease, and recurrence (which was considered if the patient had previous surgery or spontaneous passage of stone before presentation). All stones were documented radiologically by renal ultrasonography (US), conventional X-ray of the abdomen (KUB), and intravenous pyelography (IVP). Stones were analysis by chemical analysis (DiaSys Diagnostic System GmbH, Germeny) and character of the stone (unilateral or bilateral, single or multiple). Metabolic work up was done for patients suffering from multiple or bilateral renal stones. Metabolic work up included assessment of serum levels of calcium, phosphate, uric acid, and creatinine, Urinary 24-hrs collections were done for volume, calcium, phosphate, and uric acid , all the parameter were measured by automated analyzer Cobas Integra 400 Plus. RESULTS Children under study were aged between three months to 16 years (mean age 4.96± 4 years). 30.1% of the cases were infants aged less than two years, 44% aged from 2 to 6 years, and 25% more than 6 years. Clinical presentation of this pathology was dominated by flank pain (67%), urinary tract infection (49%) hematuria (27%), and acute renal failure (6.2%). A positive family history of urolithiasis was recorded for 34 patients (20%). Urolithiasis was more frequent among boys. The sex ratio was 2.8:1 (129 boys and 46 girls); ratio was 3.2:1 among infant patients, and 2.7:1 among children. Seventy five percent of the calculi were located in the upper urinary tract system and 25% in the lower one as in Fig.1. Fig. 1: distributions of urinary calculi according to stone site. Calcium oxalate stone were the commonest constituents (55.4%), followed by ammonium urate (48.6%), Struvite (15.9%), calcium phosphate (11.4%), uric acid stones (8%), and cystine stones (5.7%). The components of the upper urinary tract calculi were calcium oxalate (40%), ammonium urate (35.4%) and calcium phosphate (21%), whereas the main components of the lower urinary tract calculi were ammonium acid urate (23%), struvite (9.1%), and calcium oxalate (10.4%). There was significant association between upper urinary tract and calcium phosphate stones, and cystine stones P< 0.028, 0.045 respectively, and lower urinary tract with Struvite stones P<0.0001. Cystine stones were more 0% 5% 10% 15% 20% 25% 30% 35% 40% 45% 50% Kidney Bilateral Multiple