Saudi Journal of Kidney Diseases and Transplantation

: 2010  |  Volume : 21  |  Issue : 1  |  Page : 181--184

Clinical manifestations and etiology of renal stones in children less than 14 years age

Mohsen Akhavan Sepahi1, Akram Heidari2, Ahmad Shajari3,  
1 Department of Pediatric Nephrology, Clinical Research Development Center, Iran
2 Department of Epidemiology, Qom University of Medical Sciences, Qom, Iran
3 Department of Pediatric Nephrology, Yazd University of Medical Sciences, Yazd, Iran

Correspondence Address:
Mohsen Akhavan Sepahi
Pediatric Nephrologist, Clinical Research Development Center of Qom University of Medical Sciences, Qom


Urolithiasis is one of the commonest problems in pediatric nephrology. Prevalence of urolithiasis in pediatric patients is increasing. The purpose was to properly diagnose and treat with the special attention to the risk factors. This study is case-series and was performed on 100 pediatric patients for evaluation of clinical manifestation and etiology of renal stone in Qom. Hundred Children, fewer than 14 years old with mean age of 3.32 years, were included (54% male). Etiology of urolithiasis in 5% was unclear. Metabolic disorders found in patients were mainly: Hypocitraturia in 54, hyperoxaluria in 14, hyperuricosuria in 25, cystinuria in 6, hyper­calciuria in 28 and phosphaturia in 8 patients. The main clinical presentation was fever, pain, irri­tability, dysuria and hematuria. Family history of urolithiasis was found in 23% of patients and 54% presented with urinary tract infection (UTI). We conclude that majority of patients were symptomatic and hypocitraturia was the commenest risk factor among others.

How to cite this article:
Sepahi MA, Heidari A, Shajari A. Clinical manifestations and etiology of renal stones in children less than 14 years age.Saudi J Kidney Dis Transpl 2010;21:181-184

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Sepahi MA, Heidari A, Shajari A. Clinical manifestations and etiology of renal stones in children less than 14 years age. Saudi J Kidney Dis Transpl [serial online] 2010 [cited 2020 Sep 23 ];21:181-184
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Full Text


Urolithiasis is increasingly recognized in pe­diatric patients and is encountered in a variety of clinical settings. [1],[2]

The wide geographic variation in the inci­dence of urolithiasis in childhood is related to climatic, dietary, and socioeconomic factors. Approximately 7% of urinary calculi occur in children younger than 16 years of age. [3],[4],[5]

Many children with stone disease have a me­tabolic abnormality. [6],[7],[8]

Although stone disease is one of the most common afflictions of modern society, it has been described since antiquity. With westerni­zation of global culture, however, the site of stone formation has migrated from the lower to the upper urinary tract and the disease once limited to men is increasingly gender blind. Revolutionary advances in the minimally in­vasive and noninvasive management of stone disease over the past 2 decades have greatly facilitated the ease with which stones are re­moved. Given the frequency with which stones recur, the development of a medical prophy­lactic program to prevent stone recurrences is desirable. [9],[10],[11]

The lifetime prevalence of kidney stone disease is estimated at 1% to 15%, with the probability of having a stone varying according to age, gender, race, and geographic location. [12],[13],[14]

Stone disease typically affects boys more co­mmonly as much as two to three times more frequently than females. [2],[3] Upper urinary tract stones occur more commonly in boys than girls by a ratio of 1.4:1 to 2.1:1. [4],[16],[17]

The physical process of stone formation is a complex cascade of events that occurs as the glomerular filtrate becomes supersaturated with respect to stone-forming salts, such that di­ssolved ions or molecules precipitate out of so­lution and form crystals or nuclei. Once formed, crystals may flow out with the urine or become retained in the kidney at anchoring sites that promote growth and aggregation, ultimately leading to stone formation. Most "spontaneous" stones are composed of calcium, oxalate, or phosphate crystals; others are due to uric acid, cystine, or ammonium crystals, or phosphate crystals, or a combination of these substances. However, the presence of molecules that raise the level of supersaturation needed to initiate crystal nucleation or reduce the rate of crystal growth or aggregation, prevents stone forma­tion from occurring on a routine basis. [18],[19],[20] Re­nal calculi develop from crystals that form on the calyx and aggregate to form a calculus.

Urine must be supersaturated for stones to form. Supersaturation alone is not sufficient for crystallization to occur in urine, owing to the presence of urinary inhibitors. Citrate, diphos­phonate, magnesium ion, nephrocalcin, uro­pontin, and Tamm-Horsfall protein are impor­tant inhibitors of crystal nucleation, growth, or aggregation. [21],[22]

To this end, we wanted to understand the etio­logy, epidemiology, and pathogenesis of pedia­tric urinary tract stone disease in Qom.


We studied 100 children aged less than 14 years, from inpatient as well as out patient pediatric clinics in the region of Qom, Iran presenting with urolithiasis from December 2007 to September 2008.

Demographic variables, sex and age of each patient were recorded in a data form. After re­cruitment, all patients underwent physical exa­mination and laboratory tests.

Following laboratory investigations were per­formed:

ABG, serum Na, Ca, Phos, K, Alkaline phos­phatase, Albumin, uric acid and urine 24 hour for Na, Ca, Phoa, K, uric acid, Creatinine, Oxa­late, Citrate and Cystine.

This study was approved by the Clinical Re­search Development Center and Ethics Com­mittee of Qom University of Medical Science.


Among the Hundred patients, 54 were boys (54%) and 46 were girls (46%) [Table 1], with ages ranging from 20 days to 14 years, Male to female ratio was 1.19:1.The median age for the group under study was 3.32 years [Table 2].

Etiology of urolithiasis was multifactorial in 73.7% (70 patients), monofactorial in 26.3% (25 patients) and the cause of 5% (5 patients) was unclear.

Metabolic disorders are shown in [Table 2] ma­jority (68%) having hypocitraturia.

The main clinical presentation was hematuria [Table 3].

Family history of urolithiasis was found in 23% of patients. Among total of 100 urolithia­sis patients studied, 54% presented with UTI.


An increasing incidence of urolithiasis over­all in recent decades has been noted in popu­lation-based studies in industrialized countries. [1],[4]

There is a wide variation in prevalence of urolithiasis in different countries. The lifetime prevalence of kidney stone disease is estimated at 1% to 15%. With westernization of global culture, prevalence of urolithiasis in Iran like other countries has increased, so we decide to evaluate prevalence and etiology of urolithia­sis in Qom region.

Early diagnosis of urolithiasis is necessary to decrease the morbidity rate. These study inclu­ded 100 children with documented urolithiasis by ultrasonography. Results of our study show that: among the 100 patients, boys had a mild preponderance for stone disease overall similar to other studies from United States, United Kingdom, Brazil, and Armenia. [4],[5],[6],[20],[23]

Hypocitraturia was the main cause of uroli­thiasis in our study. Citrate is a naturally occu­rring inhibitor of calcium oxalate and calcium phosphate crystallization. [4],[24] In a study of pe­diatric patients by Tekin and colleagues, uri­nary citrate excretion was significantly lower in calcium stone former than in a control group of healthy children, [24] Hyperoxaluria accounted for 14.7% of our patients' cause for urolithia­sis similar to other reported prevalence of 2 to 20%. [25]

In our study hyperuricosuria was present in 26.3% a higher percentage than 2 to 10% re­ported in other studies. [2],[10],[15],[19] Hypoasthenuria is thought to promote increase uric acid ex­cretion but this needs to be further clarified in our population.

Cystinuria was identified in 6.3% of patients, similar to other reports of 2 to 7% in children with stones. An inherited defect in the renaltubular reabsorptive transport of cystine and the dibasic amino acids accounts for the high concentration of cystine in the urine of patients with this disorder.

In our study hypercalciuria was 29.4% (28 patients) similar to the reported prevalence of 30 to 50% of identified metabolic factors in children and adolescents with urolithiasis. [4],[10],[14],[19]

Rarely urolithiasis is asymptomatic. [4],[5],[6] In our study 90% (90 patients) were symptomatic.

Symptoms of renal colic and gross hematuria, pathognomonic of urolithiasis in adults, are less reliable in children. Flank or abdominal pain or hematuria was the main initial presenting feature in our patients similar to other reports however is present in just 56% of children from birth to 5 years of age. [1],[8],[19],[23]

In conclusion, common clinical manifestation and symptoms of urolithiasis in our patients were hematuria, dysuria, fever, pain. Hypoci­traturia being the commonest cause of uroli­thiasis followed by other known factors.

It is therefore recommended that in any child suspected of urolithiasis, prompt medical work up including sonography should be performed.


We thank other pediatricians in the children hospital and Dr. Hejazee, for allowing us to study their patients and for reviewing clinical notes.


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