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Saudi Journal of Kidney Diseases and Transplantation
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RENAL DATA FROM ASIA - AFRICA  
Year : 2015  |  Volume : 26  |  Issue : 6  |  Page : 1241-1245
Urinary screening for asymptomatic renal disorders in pre-school children in Enugu metropolis, South-east Nigeria: Useful or useless


1 Pediatric Nephrology Unit, Department of Pediatrics, University of Nigeria Teaching Hospital, Ituku Ozalla, Enugu, Nigeria
2 Pediatric Surgery Unit, Department of Surgery, Enugu State University Teaching Hospital, Enugu, Nigeria
3 Department of Medical Biochemistry, College of Medicine, Enugu State University of Science and Technology, Enugu, Nigeria
4 Department of Radiation Medicine, University of Nigeria Teaching Hospital, Enugu, Nigeria
5 Department of Pediatrics, Enugu State University Teaching Hospital, Enugu, Nigeria

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Date of Web Publication30-Oct-2015
 

   Abstract 

To evaluate the usefulness of simple screening tests such as urinalysis and blood pressure measurement in the early detection of renal disorders in pre-School children, we used a multi-staged random sampling method to select subjects from registered nursery schools within Enugu metropolis in south-east Nigeria. We selected 630 children for this cohort study. There was a prevalence of 2.7%, 0% and 1.9% for asymptomatic proteinuria, hematuria and hypertension, respectively. There was no age, gender or social class preponderance (P = 0.44). Hypertension seemed to be limited to children close to the age group of five years (P <0.001). No correlations could be documented between asymptomatic proteinuria, hematuria or hypertension. The prevalence of persistent proteinuria was found to be 1.6% and the mean urinary protein excretion estimation (spot urine protein/creatinine) was 1.88 g/mg ± 0.53, with a mean glomerular filtration rate of 78.7 ± 12.6 mL/min/1.73 m 3 . Renal ultrasonography revealed abnormal findings in 30% of the children with persistent proteinuria. Asymptomatic persistent proteinuria with or without hematuria and hypertension could be a presumptive evidence of an underlying renal parenchymal disease and should be properly investigated and followed-up.

How to cite this article:
Odetunde OI, Odetunde OA, Neboh EE, Okafor HU, Njeze NR, Azubuike JC. Urinary screening for asymptomatic renal disorders in pre-school children in Enugu metropolis, South-east Nigeria: Useful or useless. Saudi J Kidney Dis Transpl 2015;26:1241-5

How to cite this URL:
Odetunde OI, Odetunde OA, Neboh EE, Okafor HU, Njeze NR, Azubuike JC. Urinary screening for asymptomatic renal disorders in pre-school children in Enugu metropolis, South-east Nigeria: Useful or useless. Saudi J Kidney Dis Transpl [serial online] 2015 [cited 2019 Jul 23];26:1241-5. Available from: http://www.sjkdt.org/text.asp?2015/26/6/1241/168656

   Introduction Top


Renal disease in children varies in presentation, just like other childhood illnesses. The pattern of childhood renal disorders is similar in most parts of the world, although the frequency of occurrence of the various types appears to be different. [1] Childhood renal disorders may be symptomatic or asymptomatic in presentation. Both forms of presentation could result in significant morbidity and mortality; hence, the necessity for adequate and equal attention in their management. [2] Proteinuria and/or hematuria, with or without hypertension, are frequent but not specific signs of renal disorders. However, they neither prove the presence of nor exclude the possibility of renal disorders. For this reason, the discovery of proteinuria and/or hematuria, with or without hypertension, should always be followedup by proper evaluation. Studies have shown that childhood renal disorders detected by urine screening have a better prognosis when compared with those presenting with massive proteinuria and/or gross hematuria. [3],[4]

The early detection of the asymptomatic phase of renal disorders has been suggested to play a significant role in preventing mortality from the disease. [3],[4],[5],[6]

The prevalence rate of renal disease in children in Enugu, South-East Nigeria, is 4%, [7] while it is 5.25% in another part of the country. [8] Late presentation with high mortality is a common scenario in the setting. [9]

We aimed in this study to evaluate the usefulness of simple screening tests such as urinalysis and blood pressure measurement in the early detection of renal disorders in preSchool Nigerian children.


   Subjects and Methods Top


Enugu is the capital city of Enugu State, South-East Nigeria, which has a population of 3.5 million people and about 10% are of the pre-school age group (2006 Nigeria national census). The Enugu metropolis comprises three local government areas (Enugu East, Enugu North and Enugu South). Four nursery schools per local government area that constituted the Enugu metropolis were selected by systematic random sampling from a constructed sampling frame of 75 registered nursery schools. A multi-staged random sampling method was used to select a total of 630 children for this study.

Written informed consents were obtained from the parents/caregivers of the subjects before enrolment into the study. The ethical committee of the University of Nigeria Teaching Hospital (UNTH) approved the study and permission was also obtained from the State Ministry of Education before the commencement of the study.

The exclusion criteria included age <2 or >5 years; presence of symptoms of renal disease such as dysuria, increased urinary frequency or urgency; macroscopic hematuria and facial or pedal edema; presence of fever one week prior to the study; and absence of parental or caregiver's consent.

In each of the nursery schools, we distributed pre-forms containing the instructions and information to the caregivers before the date of urine collection. The pre-forms explained the nature and purpose of the study as well as instructions on how to collect the early morning urine of the children. The physical examination of the children included blood pressure, height, weight, pulse rate and temperature measurements. We distributed clean universal bottles to collect the early morning urine.

Tested within 4 h after collection, each urine specimen was divided into two aliquots. Urinalysis was performed on the uncentrifuged first aliquot of urine specimen using Combi 9 test dip stick strips (Machery-Nagel D-52313 Duren, Germany) by the investigators by adhering to the manufacturer's instruction The second aliquot of the urine specimen were then transferred to the 10 mL test tubes, which were then serially labeled and sent for microscopy. The specimens were centrifuged at 2000 rpm for 5 min. The microscopy was performed on the sediments to determine the presence of cast, red blood cells, white blood cells and crystals. Urinalysis was performed within 4 h of urine collection.

The performance of the reagent strip was standardized by testing a known specimen to which blood and protein were added in the laboratory whenever a new container was first opened as well as randomly during the course of utilizing one container of reagent strips. Only one of the authors performed dipstick urinalysis on the urine samples; therefore, observers' error in interpreting the color changes in the strips was minimized. The proteinuria was graded as follows + (30 mg/dL); ++ (30- 100 mg/dL); +++ (100-300 mg/dL); ++++ (1000 mg/dL and above). Proteinuria of (+) or more were accepted as significant while hematuria of trace and above were accepted as significant.

Children with abnormal urinalysis findings, with or without elevated blood pressure, were re-evaluated by repeat of the urinalysis and blood pressure measurements within two weeks of the first urinalysis.

All the children with persistent significant urinary findings, with or without elevated blood pressure, were invited for further investigation at the University of Nigeria Teaching Hospital (UNTH), Enugu. On presentation at the hospital, the children were asked to submit new specimens for both urinary protein and creatinine estimation besides blood for serum electrolytes, urea and creatinine. The analyses were performed at the Chemical Pathology Laboratory, UNTH, Enugu. The spot urinary protein and creatinine were performed to evaluate the protein/creatinine ratio. Renal ultrasound was also performed on each of the children by a consultant radiologist. All the children with suspected renal disorders were referred to the pediatric clinic of the UNTH for further management and follow-up.


   Statistical analysis Top


The raw data were collected into a Microsoft access file. The qualitative data of proteinuria and hematuria (+, ++, etc.) were analyzed using the Chi-square test and Fischer's exact test when an expected cell value was <5. The quantitative data, e.g. blood pressure in mm Hg, glomerular filtration rate (GFR) in mL/min/1.73 m 3 , serum electrolytes in mmol/L, urea in mmol/L, creatinine in μmol/L and urine protein/creatinine ratio in mg/day are presented as tables and analyzed using the Student "t" test. Data processing was performed using the Statistical Package for Social Sciences (S.P.S.S) version 17.0. The level of significance was set at P ≤0.05.


   Results Top


Of the 630 study children, 17 (2.7%) had varying degrees of proteinuria; [Table 1] shows the almost even distribution of the proteinuria across the age groups.
Table 1: Age distribution of subjects with proteinuria.

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Ten (1.6%) children had persistent proteinuria after the repeat urinalysis and were further investigated. Microscopy of the urine on the repeat urinalysis revealed numerous white blood cells (WBCs) in two (20%) children who were female and aged between three and five years. The urinary protein/creatinine ratio (Up/Cr) was used to estimate the 24-h proteinuria; the mean of Up/Cr was 1.88 ± 0.53 g/24 h (range 1.25-2.91 g/24-h). The results of serum electrolytes, urea and creatinine among the subjects with persistent proteinuria were basically unremarkable.

The GFR in the patients with persistent proteinuria was estimated using the height/ plasma creatinine ratio. The value obtained ranged from 64 to 106 mL/min/1.73 m 3 , with a mean of 78.7 ± 12.6 mL/min/1.73 m 3.

All the subjects with persistent proteinuria (n = 10) had normal kidney size and echotexure, but poor corticomedullary differentiation was seen in three (30%) children.


   Discussion Top


Previous screening studies on asymptomatic proteinuria, hematuria and other urinary abnormalities with or without elevation of blood pressure had been virtually restricted to school-age children and adolescents. [10],[11] This study focused on the pre-school-age children as the peak age of renal disorders in children in Enugu is between five and seven years of age. [7],[8] In this study, the prevalence of proteinuria was found to be 2.7%. This compares favorably with the 0.6-6.3% range obtained in other studies. [11],[12] The prevalence of proteinuria in this study was lower than the 7-10% range reported in a previous study in Nigeria. [13] Ekunwe and Odujinrin [14] noted a higher figure of 26.1% in their study. Falsepositive results in their study could be due to alkaline [15] and concentrated urine. [16] In this study, the first early morning urine samples were collected at home and tested within 4 h of collection. Nevertheless, Vehaskari and Rapola [16] did not report any significant change in the rate in urine samples tested after 24-h storage.

The lower prevalence of proteinuria could be related to the age of the study population as most of the studies observed an increase in the prevalence of proteinuria with age. [13],[14],[15],[16] Furthermore, in our study, the prevalence of proteinuria was similar in all ages from age two to five years, with no difference in the prevalence of proteinuria in both genders.

In our study, the prevalence of persistent proteinuria was found to be similar to the findings of Vehaskari and Rapola [16] and Dodge et al. [17]

The prevalence of hematuria of 0% in our study was a significant negative finding. This is in consonance with the study by Oviasu and Oviasu, [10] but in contrast to the prevalence of 2.6%, 3.8% and 3.9% reported from previous studies by Akinkugbe, [18] Abdulrahman [19] and Elegbe et al, [20] respectively. The higher prevalence rate in the latter was ascribed by the authors to schistosomiasis. [18],[20] Schistosomiasis is not a known local environmental problem in the population where our study was carried out. No pupil showed a combination of proteinuria and hematuria, making the prevalence of the combination 0%, which agrees with the findings of Oviasu. [10]

On further investigation, the mean estimated GFR was found to be significantly lower than the value Okoro and Onwuameze reported for healthy children who served as controls in their study. [21]

In an environment where consent for renal biopsy is not readily given, especially in an asymptomatic subject, in order to establish renal pathology, radiological studies or ultrasonography can be useful alternatives. [22],[23] The renal ultrasonic finding in the children with persistent proteinuria revealed poor corticomedullary differentiation in three (30%) of them. This could be an evidence of parenchymal renal disorder. [23],[24]

We conclude that early detection of the asymptomatic phase of renal disorder by early screening of children may identify patients with parenchymal kidney disease and possibly help prevent the morbidity and mortality in this population.


   Acknowledgment Top


authors acknowledge the management of the University of Nigeria Teaching Hospital for partly funding the research (FWCP part II research grants).

Conflict of Interest

The authors declare that they have no competing interests.

 
   References Top

1.
Hamed R. Childhood renal disorders in Jordan. J Nephrol 1995;8:165-6.  Back to cited text no. 1
    
2.
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Cho BS, Kim SD, Choi YM, Kang HH. School urinalysis screening in Korea: prevalence of chronic renal disease. Pediatr Nephrol 2001;16:1126-8.  Back to cited text no. 3
    
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Gorelick MH, Shaw KN. Screening tests for urinary tract infection in children: A metaanalysis. Pediatrics 1999;104:e54.  Back to cited text no. 6
    
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Ikimalo FE, Eke FU, Nkanginieme KE, Ikimalo J. Urinary screening for detection of asymptomatic hematuria and proteinuria in children in urban and peri-urban schools in Port Harcourt. Niger J Paediatr 2003;30:1-6.  Back to cited text no. 11
    
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Murakami M, Yamamoto H, Ueda Y, Murakami K, Yamauchi K. Urinary screening of elementary and junior high-school children over a 13-year period in Tokyo. Pediatr Nephrol 1991;5:50-3.  Back to cited text no. 12
    
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Ekunwe EO, Odujinrin OM. Proteinuria and blood pressure profile of Lagos school children. Niger J Paediatr 1989;16:15-22.  Back to cited text no. 14
    
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Wagner MG, Smith FG Jr, Tinglof BO Jr, Cornberg E. Epidemiology of proteinuria. A study of 4,807 schoolchildren. J Pediatr 1968; 73:825-32.  Back to cited text no. 15
[PUBMED]    
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Vehaskari VM, Rapola J. Isolated proteinuria: analysis of a school-age population. J Pediatr 1982;101:661-8.  Back to cited text no. 16
[PUBMED]    
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Dodge WF, West EF, Smith EH, Bruce H 3rd. Proteinuria and hematuria in schoolchildren: epidemiology and early natural history. J Pediatr 1976;88:327-47.  Back to cited text no. 17
    
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Akinkugbe FM, Akinwolere OA, Oyewole AI. Asymptomatic baecteriuria and other urinary abnormalities in children in Ibadan. Niger J Paediatr 1988;15:11-8.  Back to cited text no. 18
    
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Elegbe IA, Elegbe I, Amusan K. Screening for urinary tract infections in asymptomatic elementary school children in Ile-Ife, Nigeria. J Trop Pediatr 1987;33:249-53.  Back to cited text no. 20
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Okoro BA, Onwuameze IC. Glomerular filtration rate in healthy Nigerian children and in children with sickle cell anaemia in a steady state. Ann Trop Paediatr 1991;11:47-50.  Back to cited text no. 21
    
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Curranno G. The genitourinary tract. In: Silverman FF, Frederic N, Kuhn JP, editors. Essentials of Caffey's Pediatric X-ray Diagnosis. Chicago: Year Book Medical Publisher; 1990. p. 653-733.  Back to cited text no. 22
    
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Avni EF, Vandemerckt C, Braude P, Detemimerman D, van Gansbeke D, Schulman CC. Sonographic evaluation of renal inflammatory diseases in children. World J Urol 1988;6:18-21.  Back to cited text no. 23
    
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Leonidas JC, McCauley RG, Klauber GC, Fretzayas AM. Sonography as a substitute for excretory urography in children with urinary tract infection. AJR Am J Roentgenol 1985; 144:815-9.  Back to cited text no. 24
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Correspondence Address:
Odutola Israel Odetunde
Pediatric Nephrology Unit, Department of Pediatrics, University of Nigeria Teaching Hospital, Ituku Ozalla, Enugu, Enugu State
Nigeria
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DOI: 10.4103/1319-2442.168656

PMID: 26586065

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    Abstract
   Introduction
   Subjects and Methods
   Statistical analysis
   Results
   Discussion
   Acknowledgment
    References
    Article Tables
 

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