Sonographic measurement of renal size in normal North Indian children. Sonographic measurement of renal size in normal North Indian children

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1 Sonographic measurement of renal size in normal North Indian children Original Research Article ISSN: (P) Sonographic measurement of renal size in normal North Indian children Abdul Hamid 1,Syed Tariq 1,Mohammad Ishaq 1,Farooq Ahmad Ganie 2*,Shagufta Roohi 3,Shazia Akhter 1,Mohsin Rashid 1 1 Department of Pediatrics Government Medical College, Srinagar, Kashmir, India 2 Department Cardio-vascular and Thoracic Surgery, SKIMS, Srinagar, Kashmir, India 3 Departmentt of Microbiology, SKIMS, Srinagar, Kashmir, India *Corresponding author farooq.ganie@ymail.com How to cite this article: Abdul Hamid, Syed Tariq, Mohammad Ishaq, Farooq Ahmad Ganie,Shagufta Roohi, Shazia Akhter, Mohsin Rashid. Sonographic measurement of renal size in normal North Indian children. IAIM, 2015; 2(3): Available online at Received on: Accepted on: Abstract Objective: To determine the renal size in normal North Indian children by renal sonography. Design: Hospital based (outpatient based) cross sectional observational study. Material and methods: Total 1198 normal children aged 1 month to 12 years were included in the study. Sonographic assessment of renal size (length, width and thickness) was performed using Philips, multi frequency (3.5, 5 and 7.5 Mhz) linear and convex probes in B-mode. The mean renal dimensions and volume were calculated for each age group with ± 2SD. The renal length and calculated renal volume were correlated with somatic parameters like age, weight, height, and body surface area (BSA). Linear Regression equations were derived for each variable. Results: A strong correlation was seen between renal size and renal volume with various somatic parameters (age, weight, height, BSA), (coefficient of correlation = 0.9). Conclusion: This study provides values of renal size (mean ± 2SD) in normal North Indian children and its correlation with age, weight, height, and BSA. Renal size can be easily calculated by derived linear regression equation. Key words Somatic parameter, Kashmiri, Kidney, Size, Sonography. Introduction Renal size is an important parameter in the assessment of a child with renal disease. Decrease or increase in kidney size is an important sign of renal disease [1]. Renal size can be estimated by measuring renal length, renal thickness and volume. Since the change in renal length may be an evidence of disease, it is Page 47

2 important that we have normal reference values ±2 SD of the right and left kidneys were in children in relation to their age, gender, calculated separately for age group. height, weight, body surface area and ethnicity. Age related nomograms are most commonly Statistical analysis used to interpret normal renal length. However Regression equations and coefficient of these nomograms are based on a healthy correlation were derived for each pair of Western population, while as only few studies variables. Coefficient of correlation was derived are from Indian subcontinent, needs a more by Pearson coefficient of correlation. Analysis research to settle the knowledge gap. Hence it was performed using SPSS 17.0 software. would be useful to develop our own Continuous variables were presented as mean ± nomograms for our children using an adequate SD and categorical variables were presented as sample size. absolute numbers and percentage. Normally distributed continuous variables were compared Material and methods using un paired t test. Linear regression analysis was done using kidney size and kidney volume as dependent variables and age, height, weight, and BSA as the independent variables. P value <0.05 was taken as significant. All normal healthy siblings of patients attending the out-patient clinics, and those visiting vaccination center aged 1 month to 12 years were included in study. Age, weight, and height were recorded at the time of the examination. After taking proper consent from parents, infants were weighed on an infant weighing scale and older children on beam balance. Weights were recorded to the nearest 100 gm. The supine lengths were measured on an infantometer in children below 2 years and the standing height was measured on a stadiometer in children above 2 years to the nearest 1 mm. The body surface area (BSA) was calculated from weight [2]. A Philips real-time mechanical sector scanner of 3.5, 5, and 7.5 Mhz frequency with electronic calipers was used to measure the length, width and thickness of each kidney with the child placed in a supine and oblique position. The maximal renal length was recorded after re- angulations. positioning the probe in several Renal width was measured at renal hilum and thickness was recorded from transverse scans showing the maximum dimension. All the measurements were made by one investigator. The renal volume was calculated by the formula: Volume = length width breadth [3]. The mean length, width and volume xclusion criteria Children suffering from any acute or chronic ailment, any metabolic or chromosomal abnormality, or apparent syndromic child, and those below the age of 1 month, were excluded from study. Results The study was done over 1198 normal children aged from 1 month to 12 years in 16 age groups. 51% (618) males and 49% (580) were females. The average kidney size ranged from mean size of 4.42 ± 0.11 cm in 1 month to 8.72 ± 0.13 cm in 12 years old children. The average kidney volume measured by ultrasonography ranged from mean 9.37 ± 0.66 ml at 1 month to ±2.09 ml at 12 years as per Table 1. There was a good correlation of renal size with age, body weight, body height and BSA. The best correlation was of renal length with the body height (r = 0.978) and (r = 0.98) in females and males respectively and body surface area (r = 0.979) and (r = 0.97) in females and males respectively. Page 48

3 Renal volume also had good correlation with examination, does not require sedation, and is body height in cm (r = 0.97) and (r = 0.97) in easily available and reproducible [11]. females and males respectively and body surface area (r = 0.96) and (r = 0.96) in females Conclusion and males respectively. In clinical practice, the body height and weight can be quickly recorded to compare the actual Linear regression equations for predicting renal length with the renal norm. Since the variable (renal length and renal volume) from estimation of renal volume requires independent variables (age, height, weight and measurement of three dimensions of the BSA) were obtained as per Table - 2 and Table - kidney, the error associated with renal volume 3. increases in geometric proportion. Hence it is Discussion simpler to use renal length as a yardstick for comparing renal growth with body growth. Due The purpose of our study was to see renal to the large sample size, this study represents parameters (length, breadth, width and volume) the population more closely. by sonography in normal Kashmiri children and compare with various somatic variables (age, The renal size norms developed by this study weight, height, body mass index, and body provide normal kidney length and volume range surface area). for children according to age and body size. There was significant correlation of renal size with age, body weight, Height, BSA in our study particularly more with height and BSA. Other studies have revealed similar results [4, 5, 6, 7]. There was a good correlation between kidney volume with age, body weight, Height and BSA particularly more with height and BSA. Other studies have revealed similar results [4, 8]. Renal lengths did not display a significant difference in males and females as per Table - 4. Other studies have also reported similar observations [5, 9, 10]. Sonography has become an important part of the pediatric imaging armamentarium, perhaps the most important. Its strengths are many, to begin, it does not use ionizing radiation, does not require administration of intravenous contrast agents, although several ultrasound contrast agents have been recently developed that can increase the accuracy of the imaging References 1. Davis ID, Abner D. Glomerular disease. In: Kliegman RF, Behrman R, Jenson HB, Stanton BF eds. Nelson Textbook of Pediatrics. 18 th edition. Philadelphia: Saunders; 2007, p Vaughan VC III, Iris LF. Growth and development. In: Behrman, Kliegman, Nelson, Vaughan, editors. Nelson Text book of pediatrics, 14 th edition, WB Saunders Company Harcourt Brace Jovonovich Inc, 1992, p Han BK, Babcock DS. Sonographic measurements and appearance of normal kidneys in children. AJR Am JRoentgenol., 1985; 145: Aotiv, K Mehta, U Ali, M Nadkarni. Sonographic measurement of renal size in normal Indiann Chidren. Indian Pediatrics, 2012; 49( (7): Haugstvedt S, Lundberg J. Kidney size in normal children measured by Page 49

4 sonography. Scand J 9. Simsek, Safak AA, Bahcebasi T. UrolNephrol., 1980; 14(3): Sonographic assessment of the normal 6. Boo Won Kim, Min Kyoung Song, limits and percentile curves of liver, Sochung Chung, Kyo Sun Kim. spleen, and kidney dimensions in valuation of kidney size in children: a healthy school aged children. J pilot study of renal length as a surrogate Ultrasound Med, 2005; 24(10): of organ growth. Korean J 10. Andreja, Dvorsak rker, Alojz Gregoric: Pediatr., 2012; 55(2): Sonographic measurements of renal size 7. Adeela Arooj, Jostinah Lam, Yeoh J. Wui, in slovenian population of children. ko Supriyanto. Comparison of Renal ZdravniskiVestnik-Slovenian Medical Size among Different thnicities. Journal, 2011; 80(1). International Journal of Biology and 11. Robbin ML. Ultrasound contrast agents: Biomedical ngineering, 2011; 4(5): 221- A promising future. RadiolClin North 229. Am, 2001; 39(3): Purushottam K. Dixit, S.B. Sahai, B. Rath, Anju Garg, Veena Chowdhury. Norms for renal parenchymal volume in Indian children. Indian Pediatr., 1994; 31(9): Source of support: Nil Conflict of interest: None declared. Page 50

5 Sonographic measurement of renal size in normal North Indian children Table 1: Mean renal length and volume of study children. (n = 1198) ISSN: (P) Age groups WT (Kg) HT (cm) BSA (m 2 ) avg_kidney size(cm) avg_wd (cm) avg_bd (cm) avg_vl (cm 3 ) Mean ± SD Mean ± SD Mean ± SD Mean ± SD Mean ± SD Mean ± SD Mean ± SD 1-3month 3-6 months 6-9months 9-12 months 3.40 ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± y r 8.79 ± ± ± ± ± ± ± y r s ± ± ± ± ± ± ± y r s ± ± ± ± ± ± ± y r s ± ± ± ± ± ± ± y r s ± ± ± ± ± ± ± y r s ± ± ± ± ± ± ± y r s ± ± ± ± ± ± ± y r s ± ± ± ± ± ± ± years years years 1 2 y e a r s ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± 2.09 Page 51

6 Table - 2: Depicts the correlation of kidney size with anthropometric variables and predicted regression equations. V a r i a b l e R r Square P v a l u e Predicted quation F M A A g e W e i g h t H e i g h t B S A < Age < Wt < Ht < BSA M A L A g e W e i g h t H e i g h t B S A < Age < Wt < Ht < BSA Table - 3: Depicts the correlation of kidney size with anthropometric variables and predicted regression equations. V a r i a b l e R r S q u a r e P v a l u e Predicted quation F M A L A g e W e i g h t H e i g h t B S A < Age < W t < (-) Ht < (-) BSA M A L A g e W e i g h t H e i g h t B S A < Age < W t < (-) Ht < (-) BSA Page 52

7 Sonographic measurement of renal size in normal North Indian children Table - 4: Depicts the differencee in males and females in renal lengths. ISSN: (P) F e M e a m a l e M a l n Std. Deviation M e a n e Std. Deviation P v a l u e avg_kidneysize 6. 6 a v g _ W D 2. 9 a v g _ B D a v g _ V L Page 53