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Saudi Journal of Kidney Diseases and Transplantation
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RENAL DATA FROM THE ARAB WORLD  
Year : 2013  |  Volume : 24  |  Issue : 5  |  Page : 1055-1061
Idiopathic urolithiasis in Tunisian children: A report of 134 cases


1 Department of Biochemistry and Toxicology, University Hospital; Ecole Supérieure des Sciences et Techniques de la Santé de Monastir, Unité de Nutrition et Métaux Lourds, Monastir, Tunisia
2 Ecole Supérieure des Sciences et Techniques de la Santé de Monastir, Unité de Nutrition et Métaux Lourds, Monastir, Tunisia
3 Department of Pediatric Surgery, University Hospital, Monastir, Tunisia
4 Department of Biochemistry and Toxicology, University Hospital, Monastir, Tunisia

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Date of Web Publication12-Sep-2013
 

   Abstract 

We evaluated the metabolic and the nutritional aspects of 134 urolithiasis children in order to outline the characteristics of idiopathic urolithiasis in children. This prospective study group of 134 children (56 females, 78 males) with renal calculi was evaluated. The age range of the patients was six months to 16 years. A dietary survey was performed on every child. All patients were investigated with respect to stone localization and serum and urine risk factors. Statistical analysis of data was carried out using software SPSS 11.0 for Windows. Hypercalciuria was the most common risk factor detected in this group (28.3%). A decrease of water intake was noted in all age groups, especially in the rural area (549.6 mL/day vs. 1150.6 mL/day), and there was an increase in animal protein intake in 17 cases (mean: 1.9 g/kg). In addition, increased intake of starchy foods and food with high oxalate content (sorgum) were detected in the ten to 16 years age group (51%) of our study. Calcium oxalate monohydrate represents the principal component of idiopathic stone (58.2%), which is more frequent in children (68%) than in infants (51.7%) (P <0.02). The major etiology of idiopathic urolithiasis highlights the influence of dietary habit in stone formers in our country. The increased occurrence of calcium oxalate stones in school age children confirms the change in the etiology of urolithiasis according to age.

How to cite this article:
Alaya A, Sakly R, Nouri A, Najjar M F, Belgith M, Jouini R. Idiopathic urolithiasis in Tunisian children: A report of 134 cases. Saudi J Kidney Dis Transpl 2013;24:1055-61

How to cite this URL:
Alaya A, Sakly R, Nouri A, Najjar M F, Belgith M, Jouini R. Idiopathic urolithiasis in Tunisian children: A report of 134 cases. Saudi J Kidney Dis Transpl [serial online] 2013 [cited 2019 Oct 20];24:1055-61. Available from: http://www.sjkdt.org/text.asp?2013/24/5/1055/118099

   Introduction Top


Until now, renal stones in developing countries were considered to be very different from those observed in industrialized countries. [1] Over the last few decades, lifestyle and dietary habits have been westernized in our country. Idiopathic urolithiasis in the upper urinary tract has become by far the most common type of urinary calculi. [2] The changing pattern of urolithiasis in the Tunisian pediatric population has been mentioned in our previous studies. [2],[3] In this study, we evaluated the metabolic and nutritional aspects of 134 children suffering from stone disease in order to outline the risk factors that contribute to idiopathic stone formation in children.


   Patients and Methods Top


One hundred and thirty-four children aged six months to 16 years with urolithiasis were admitted between 2002 and 2010 to the pediatric surgery department at the University Hospital of Monastir, Tunisia. Epidemiological data as well as mode of onset, underlying disease, imaging and laboratory analysis were recorded. The dietary habits and family backgrounds were obtained from all parents. A dietary survey was performed on every patient to measure actual food intake at the individual level by administering a food frequency questionnaire, recording weights of foods consumed and asking respondents to recall what they frequently ate before the first lithiasic symptom. Clinical examination was performed in all cases, but was incomplete in 24 patients (17.9%).

Normal values for urine constituents were defined as <4 mg/kg for calcium, <0.57 mg/kg for oxalate, <10.7 mg/kg for uric acid and >320 mg/kg for citrate. [4],[5] Interpretation was based on ratios (x over creatinine). Briefly, the upper limits of normal (mol/mL) used for the age groups 1-3/3-5/5-7 and >7 years were for calcium 1.4/1.1/0.8/0.7, for oxalate 0.12/0.08/0.07/0.06 and for uric acid 1.3/1.1/ 0.8/0.55, respectively.

All stones were documented by ultrasound and intravenous urography. All stones were examined by infrared spectroscopy in the laboratory. The structure of each one was established using a stereomicroscope to define the morphology of the stone and to select its parts (nucleus or core, internal section and external surface) in order to determine its molecular and crystalline composition by infrared spectroscopy. A stone component was considered as the main component if it exceeded 70% of the total stone composition.

Statistical analysis of data was performed using SPSS 11.0 for Windows. Mean values and standard deviation were calculated for all groups. Chi-square test was applied to compute the significance of the categorical variables and P <0.05 was considered significant.


   Results Top


Between 2001 and 2009, 205 children suffering from urolithiasis were admitted to our service. One hundred and thirty-four (65.4%) children were classified as idiopathic urolithiasis. Of the 134 children with urolithiasis, 78 (58.2%) were males and 56 (41.8%) were females (sex ratio = 1.47). Children's age at presentation ranged from six months to 16 years (mean age 6.5 years) and 50.7% of the study group were below five years of age. Patients were predominantly from the rural areas (107 patients, 79.8%) of the central coast of Tunisia.

The upper urinary tract was most frequently affected by this pathology (68.6%). Evaluation of the detailed histories provided by the parents revealed a positive family history in 15 patients (12.7%).

Thirty-eight (28.3%) children were associated with hypercalciuria and had urinary calcium/ urinary creatinine more than 0.21 mg/mg (mean: 0.33 mg/mg)". These patients excreted more than 4 mg/kg/day calcium [range: 4.57-8.28 mg/kg/day (mean: 5.20 mg/ kg/day)] without hypercalcemia. Twenty patients (52.6%) in this idiopathic hypercalciuric group had a urinary creatinine concentration higher than the other children (mean 28.4 mg/ kg vs. 15.5 mg/kg, P <0.01), suggesting that these children have lower water intakes.

The urine Na/K ratio (mEq/mEq) was determined in 35 cases, this and ranged between 1.43 and 35.35 (mean 6.97 mEq/mEq), demonstrating a higher sodium intake in 21 cases, ranging from 1 g/day to 8.4 g/day (mean: 7.95 g/day).

Stone analysis showed a predominance of oxalate monohydrate associated with hyperoxaluria. Primary hyperoxaluria was excluded in our analysis (absence of type Ic). According to the morphological study, intermittent hyperoxaluria was suspected to be at the origin of stone building in 54 cases; however, biological analysis showed hyperoxaluria in only eight cases to be associated with whewellite stones that were metabolically active.

Twenty-four-hour urinary citrate assays performed in 20 subjects (14.9%) revealed hypocitraturia in 15 cases (mean citraturia of 106.6 mg/g creatinine) (range: 92.3-113.2 mg/g creatinine). Hypocitraturia was associated with high protein intake in only eight cases (40%). The dietary habits of the children with idiopathic urolithiasis were thoroughly investigated [Table 1] and [Table 2]. The evaluation of the content of the foods consumed demonstrated decreased water intake in all age groups, especially in the rural area (549.6 mL/day vs. 1150.6 mL/day), and increase in animal protein intake in 17 cases ranging from 1.4 g/kg to 2.4 g/kg (mean: 1.9 g/kg). Additionally, increased intake of starchy foods and food with high oxalate content (sorgum) was detected in the ten to 16 years age group (51%) of our study.
Table 1: Dietary history of stone former children. The nutrient intake was calculated from food tables after taking the dietary history.

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Table 2: Animal protein intake according to patient age and area.

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Calcium oxalate monohydrate represents the principal component of idiopathic stone (58.2%) [Table 3], which was more frequent in children (68%) than in infants (51.7%) (P <0.02) [Table 4]. The microscopic stone analysis has shown the prevalence of whewellite type Ia, with the absence of whewellite type Ic.
Table 3: Main component of idiopathic urolithiasis according to sex and age.

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Table 4: Main component of urinary stones in infants and old children with idiopathic urolithiasis.

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   Discussion Top


Urolithiasis has become more common in children over the past few decades probably as a result of rapid variations in dietary habits and increasing affluence. The change of socio-economic conditions has generated changes in the frequency and type of urolithiasis in terms of both site and physicochemical composition of the calculi. [6]

Stones appear to be particularly common in children living in Tunisia, and this study is one of the largest reported on urolithiasis in the pediatric age group of this country. [2],[3],[7],[8] Stone composition has changed substantially over the past decades in Tunisia, with a progressive increase in frequency of calcium oxalate stones. [2] This is seen even in the eastern hemisphere, where these stones have been traditionally less frequent than uric acid- and infection-associated stones. Recent epidemiology studies from different continents and countries report that calcium oxalate accounts for 60-90% of stones in children. [9],[10],[11],[12],[13],[14],[15],[16],[17]

Idiopathic urolithiasis in children has become frequent in the western world as a result of the changes in dietary habits in the last few decades. [18] There is a wide variation in the prevalence of idiopathic urolithiasis in different countries. The lowest prevalence is reported from Japan (0.6%), [19] whereas this prevalence is striking in Germany (8.6%), [20] Italy (9.1%), [21] USA (12-13%), [22],[23] Turkey (2.9%) [26] and Argentina (12.7%). [24] In our study, idiopathic urolithiasis was observed in 65.4% of the cases.

Hypercalciuria is the most common etiology of urolithiasis in children and adults. [25],[26],[27],[28],[29] Idiopathic hypercalciuria was observed in 41.8% of our study population. It was postulated that the hot climate in such geographical areas contributes to dehydration and, hence, decreased urinary volume, increased urine osmolarity and increased concentration of calcium and oxalate. [30],[31] The climate in our region is so hot that the maximum temperature exceeds 35-40°C on most days between June and September, resembling the climate of the Arabian Peninsula. In addition, the majority of patients with idiopathic stone resides in rural areas where water intake in children does not exceed 549.6 mL/ day. A low water intake was more obvious in patients with idiopathic hypercalciuria than in the other etiologic group.

Since 1986, the frequency of occurrence of kidney stone has been on a continuous rise in Tunisia. [2] Increase in upper urinary tract stone prevalence also occurred in eastern countries, where consumption of animal and vegetable proteins has considerably increased during the past few decades. [32],[33] Epidemiologic observations leave no doubt that diet plays a major, if not the most important, role in the pathogenesis of urolithiasis. [6]

Several previous studies have demonstrated the role of diet on hypercalciuria and augmented oxalate excretion. [34],[35],[36],[37],[38] Increased protein and salt intake and decreased potassium intake were commonly observed in urolithiasic children in the Western society. [37],[39],[40] Since the 60s, dietary habits have been dramatically westernized in Tunisia. [41],[42] An increase in meat and milk intake was noted whereas the cereal intake decreased. [43] In our study, patients showed an increased animal protein intake in teenage children.

Calcium oxalate stone linked to dietary habits is frequent among adults than among children. [7],[43] The relationship between frequency of main types of stones and patients' age was previously reported by Daudon et al. [44] This reflects both nutritional change and metabolism evolution depending on the patient's age. These data were widely noted in adults, [44],[45] specifically for the two forms of calcium oxalate: The whewellite (calcium oxalate monohydrate) and weddellite (calcium oxalate dihydrate). The high frequency of the whewellite form among teenage children in our study confirms the role of food-borne hyperoxaluria in developing these stones. Indeed, the dietary survey revealed an excessive consumption of chocolate and sorghum in more than half of the patients in this age group.

The ingestion of proteins has other effects on urine chemistries. Lowering of citrate excretion is the most remarkable one. [46] Hypocitraturia is one of the principal factors promoting stone formation in idiopathic stone disease, with a prevalence ranging from 8% up to 68.3%. [47] Hypocitraturia was found in 15 children, and was associated with high protein intake in only eight children. A low citrate output in stone formers may also be linked to renal defects (impairment of the sodium citrate cotransport or alteration of intracellular citrate regulation), inappropriate intestinal citrate or alkali absorption [47] or low magnesium or potassium levels. [48]

The prevalence of uric acid stone also appeared to be influenced by animal protein in the diet. [6] These data were not confirmed by our results. However, the most remarkable change in purine stones was the disappearance of uric acid anhydrous in older children. Metabolic (genetic or acquired) disorder can be considered to explain this change. However, we believe that tubular immaturity in infants associated with a lack of reabsorption of uric acid is the main reason in this case. [49]

The epidemiology of renal stones is continuing to change in our country toward a predominance of calcium oxalate stones, probably highlighting the influence of dietary habits in stone formers. The increase in calcium oxalate stones in school age children confirms the change in the etiology of urolithiasis according to age.

 
   References Top

1.Daudon M, Bounxouei B, Santa Cruz F, et al. Renal stone composition currently observed in non industrialized countries. Prog Urol 2004; 14:1151-61.  Back to cited text no. 1
[PUBMED]    
2.Alaya A, Nouri A, Najjar MF. Paediatric renal stone disease in Tunisia: A 12 years experience. Arch Ita Urol Androl 2008;80:50-5.  Back to cited text no. 2
    
3.Alaya A, Nouri A, Najjar MF. Prevalence and composition of urolithiasis in a paediatric Tunisian population. Prog Urol 2009;19:395-400.  Back to cited text no. 3
[PUBMED]    
4.Elder JS. Urinary lithiasis. In: Behrman RE, Kliegman RM, Jenson HB, eds. Urological disorders in infants and children. Philadelphia, PA: Saunders; 2000. p. 1655-9.  Back to cited text no. 4
    
5.Kroovand RL. Pediatric urolithiasis. Urol Clin North Am 1997;24:173-84.  Back to cited text no. 5
[PUBMED]    
6.López M, Hoppe B. History, epidemiology and regional diversities of urolithiasis. Pediatr Nephrol 2010;25:49-59.  Back to cited text no. 6
    
7.Kamoun A, Daudon M, Abdelmoula J, et al. Urolithiasis in Tunisian children: A study of 120 cases based on stone composition. Pediatr Nephrol 1999;13:920-5.  Back to cited text no. 7
[PUBMED]    
8.Jellouli M, Jouini R, Mekki M, Belghith M, Najjar MF, Nouri A. Urinary stones in Tunisian infants, based on a series of 64 cases. Prog Urol 2004;3:376-9.  Back to cited text no. 8
    
9.Rizvi SA, Naqvi SA, Hussain Z, et al. Pediatric urolithiasis: Developing nation perspectives. J Urol 2002;168:1522-5.  Back to cited text no. 9
[PUBMED]    
10.Al-Eisa AA. Pediatric urolithiasis in Kuwait. Int Urol Nephrol 2002;33:3-6.  Back to cited text no. 10
    
11.Sarkissian A. Pediatric urolithiasis in Armenia: A study of 198 patients observed from 1991 to 1999. Pediatr Nephrol 2001;16:728-32.  Back to cited text no. 11
    
12.Ali SH, Rifat UN. Etiological and clinical patterns of childhood urolithiasis in Iraq. Pediatr Nephrol 2005;20:1453-7.  Back to cited text no. 12
[PUBMED]    
13.VanDervoort K, Wiesen J, Frank R, et al. Urolithiasis in pediatric patients: A single center study of incidence, clinical presentation and outcome. J Urol 2007; 177:2300-5.  Back to cited text no. 13
[PUBMED]    
14.Srivastava T, Alon U. Urolithiasis in adolescent children. Adolesc Med Clin 2005;16:87-109.  Back to cited text no. 14
    
15.Orta N, López M, Moriyon J, Chavez JB. Renal diseases in children in Venezuela. Pediatr Nephrol 2002;17:566-70.  Back to cited text no. 15
    
16.Lagomarsino E, Avila D, Baquedano P, Cavagnaro F, Céspedes P. Pediatric urolithiasis. Rev Chil Pediatr 2003;74:381-8.  Back to cited text no. 16
    
17.Edvardsson V, Elidottir H, Indridason OS, Palsson R. High incidence of kidney stones in Icelandic children. Pediatr Nephrol 2005;20: 940-4.  Back to cited text no. 17
[PUBMED]    
18.Ammenti A, Neri E, Agistri R, Beseghi U, Bacchini E. Idiopathic hypercalciuria in infants with renal stones. Pediatr Nephrol 2006;21: 1901-5.  Back to cited text no. 18
[PUBMED]    
19.Kaneko K, Tsuchiya K, Kawamura R, et al. Low prevalence of hyperclciuria in Japanese children. Nephron 2002;91:439-43.  Back to cited text no. 19
[PUBMED]    
20.Manz F, Kehrt R, Lausen B, Merkel A. Urinary calcium excretion in healthy children and adolescents. Pediatr Nephrol 1999;13:894-9.  Back to cited text no. 20
[PUBMED]    
21.De Santo NG, Di Iorio B, Capasso G, et al. Population based data on urinary excretion of calcium, magnesium, oxalate, phosphate and uric acid from Cimitile (southern Italy). Pediatr Nephrol 1992;6:149-57.  Back to cited text no. 21
[PUBMED]    
22.Welch TR, Abrams SA, Shoemaker L, Yergey AL, Vieira N, Stuff JE. Precise determination of the absorptive component of urinary calcium excretion using stable isotopes. Pediatr Nephrol 1995;9:295-7.  Back to cited text no. 22
[PUBMED]    
23.O'Brien KO, Abrams SA, Stuff JE, et al. Variable related to urinary calcium excretion in young girls. J Pediatr Gastoenterol Nutr 1996; 23:8-12.  Back to cited text no. 23
    
24.Bercem G, Cevit O, Toksoy HB, Içagasioglu D, Gültekin A, Tanzer F. Asymptomatic hypercalciuria: Prevalence and metabolic characteristics. Indian J Pedaitr 2001;68:315-8.  Back to cited text no. 24
    
25.Alconcher LF, Castro C, Quintana A, et al. Urinary calcium excretion in healthy school children. Pediatr Nephrol 1997;11:186-8.  Back to cited text no. 25
    
26.Pak CY, Britton F, Peterson R, et al. Ambulatory evaluation of nephrolithiasis: Classification, clinical presentation, and diagnosis criteria. Am J Med 1980;69:14-28.  Back to cited text no. 26
    
27.Moxey-Mims MM, Stapleton FB. Hypercalciuria and nephrocalcinosis in children. Curr Opin Pediatr 1993;5:186-90.  Back to cited text no. 27
[PUBMED]    
28.Stapleton FB, Kroovand RL. Stones in childhood. In: Coe FL, Favus MJ, Pak CY, Parks JH, Preminger CH, eds. Kidney stones. Medical and surgical management. Philadelphia: Lippincott-Raven; 1996. p. 1065-80.  Back to cited text no. 28
    
29.Kingwatanakul P, Alon US. Hypercalciuria and urolithiasis in childhood. In: Trachtman H, Gauthier B, eds. Pediatric nephrology. Amsterdam: Harwood Academic Press; 1999. p. 253-68.  Back to cited text no. 29
    
30.Schwille PO, Herrmann U. Environmental factors in the pathophysiology of recurrent idiopathic calcium urolithiasis (RCU), with emphasis on nutrition. Urol Res 1992;20:72-83.  Back to cited text no. 30
[PUBMED]    
31.Al Hadramy MS. Seasonal variations of urinary stone colic in Arabia. J Pak Med Assoc 1997; 47:184-281.  Back to cited text no. 31
    
32.Yoshida O, Terai A, Ohkawa T, Okada Y. National trend of the incidence of urolithiasis in Japan from 1965 to 1995. Kidney Int 1999;56: 1899-904.  Back to cited text no. 32
[PUBMED]    
33.Sternberg K, Greenfield SP, Williot P, Wan J. Pediatric stone disease: An evolving experience. J Urol 2005;174:1711-4.  Back to cited text no. 33
[PUBMED]    
34.Osorio AV, Alon US. The relationship between urinary calcium, sodium and potassium excretion and the role of potassium in treating idiopathic hypercalciuria. Pediatrics 1997;100: 675-81.  Back to cited text no. 34
[PUBMED]    
35.Nakano M, Alon U, Jennings SS, Chan JC. Protein intake and renal function in children. Am J Dis Child 1989;143:160-3.  Back to cited text no. 35
[PUBMED]    
36.Borghi L, Schianchi T, Meschi T, et al. Comparison of two diets for the prevention of recurrent stones in idiopathic hypercalciuria. N Engl J Med 2002;346:77-84.  Back to cited text no. 36
[PUBMED]    
37.Robertson WG, Peacock M, Hodgkinson A. Dietary changes and the incidence of urinary calculi in the U.K. between 1958 and 1976. J Chronic Dis 1979;32:469-76.  Back to cited text no. 37
    
38.Holmes RP, Goodman HO, Hart LJ, Assimos DG. Relationship of protein intake to urinary oxalate and glycolate excretion. Kidney Int 1993;44:366-72.  Back to cited text no. 38
[PUBMED]    
39.Lottman H, Gagnadoux MF, Daudon M. Urolithiasis in children. In: Gearhart JP, Rink RC, Morriquand PD, eds. Pediatric Urology. Philadelphia: Saunders; 2001. p. 828-59.  Back to cited text no. 39
    
40.Pak CY. General guidelines in medical evaluation. In: Resnick MI, Pak CY, eds. Urolithiasis: A medical and surgical reference. Philadelphia: Saunders; 1990. p. 153-72.  Back to cited text no. 40
    
41.Ben Romdhane H, Khaldi R, Oueslati A, Skhiri H. Epidemiological nutritional transition in Tunisisa. Options Mediterr 2002;41:7-27.  Back to cited text no. 41
    
42.Najjar MF, Najjar F, Boukef K, et al. Pediatric urolithiasis in the region of Monastir clinical and biological study. Le Biologiste 1986;165 31-9.  Back to cited text no. 42
    
43.Daudon M. Componet analysis of urinary calculi in the etiological diagnosis of urolithiasis in the child. Arch Pédiatr 2000;7:855-65.  Back to cited text no. 43
    
44.Daudon M, Doré JC, Jungers P, Lacour B. Changes in stone composition according to age and gender of patients: A multivariate epidemiological approach. Urol Res 2004;32:241-7.  Back to cited text no. 44
    
45.Daudon M, Jungers P. Clinical value of crystalluria and quantitative morphoconstitutional analysis of urinary calculi. Nephron Physiol 2004;98:31-6.  Back to cited text no. 45
    
46.Breslau NA, Brinkley L, Hill KD, Pak CY. Relationship of animal protein-rich diet to kidney stone formation and calcium metabolism. J Clin Endocrinol Metab 1988;66:140-6.  Back to cited text no. 46
    
47.Caudarella R, Vescini F. Urinary citrate and renal stone disease: The preventive role of alkali citrate treatment. Arch Int Urol Androl 2009; 81:182-7.  Back to cited text no. 47
    
48.Schwille PO, Scholz D, Schwille K, Leutschaft R, Goldberg I, Sigel A. Citrate in urine and serum and associated variables in subgroup of urolithiasis. Results from an outpatient stone clinic. Nephron 1982;31:194-202.  Back to cited text no. 48
    
49.Oussama A, Kzaiber F, Mernari B, Semmoud A, Daudon M. Analysis of calculi by infrared spectrometry in children from the Moroccan mid-Atlas.Ann Urol 2000;34:384-90.  Back to cited text no. 49
    

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Correspondence Address:
A Alaya
Department of Biochemistry and Toxicology, University Hospital, Monastir
Tunisia
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DOI: 10.4103/1319-2442.118099

PMID: 24029284

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