Acta Paediatr 81: 326-8. 1992
Ultrasonographic screening for renal abnormalities in three-year-old -children Masako Mihara, Yuhei Ito, Keiko Fukushima, Fumio Yamashita and Miwako Tsunosue' Department of Paediatrics and Child Health. Kurume University School of Medicine, Kurume and Kurume Healih Center. Kurume', Japan
Mihara M, Ito Y, Fukushima K, Yamashita F, Tsunosue M. Ultrasonographic screening for renal abnormalities in three-year-old children. Acta Piediatr 1992;81:326-8. Stockholm. ISSN 0803-5253 We report the results of ultrasonographic screening to determine the prevalenceof renal abnormalities in children. This study was conducted simultaneouslywith a regular health check using portable realtime ultrasound equipment, from July 1988 to June 1989. Of 2920 three-year-old children resident in Kurume City, 2351 (80.5O/") were screened. Abnormalities were detected in 1 1 (0.47%)of these, involving six cases of pelvic dilatation, three cases of unilateral renal agenesis, and two cases of a unilaterally small kidney. However, the simultaneous urinalysis of these 1 1 children did not disclose these abnormalities. Our results indicate that ultrasonbgraphy is an efficient tool for screening for a silent renal abnormality. 0 Renal abnormality, ultrasonographic screening M Mihara, Department of Pediatrics and Child Health, Kurume University School of Medicine, 67 Asahi Machi. Kurume City 830, Japan
The early detection of any renal abnormality is essential in pediatric nephrology. However, renal abnormalities always present non-specific symptoms or silence, especially among children, and it is difficult to detect an abnormality by routine urinalysis. To detect the prevalence of renal abnormalities, we established an efficient screening system for three-year-old children using ultrasonography. Nationwide regular health checks for three-year-old children are conducted at Japanese local health centers, and children at this age are able to hold steady their position for the duration of an ultrasonographic examination. For these reasons, these children were selected as subjects for this study.
Subjects and methods From July 1988 to June 1989, 2351 three-year-old children (80.5% of all three-year-old children in Kurume City) were screened at Kurume Health Center. A portable real-time ultrasound scanner (ALOKA, SSD21-DX) was used for the initial screening. Each child urinated before the ultrasonographic examination and was requested to lift up any clothing for examination in a ventral position on a bed, one after another. The probe, using a 5-MHz transducer, was placed on the back region and both kidneys were screened quickly, with each examination requiring 30 to 60 s. A routine urinalysis was also performed by spot urine collection. If a kidney abnormality was detected by our ultrasonographic screening, the examinee was referred to Kurume University Hospital for further checks and confirmation
of diagnosis. Further investigations were performed on a selective basis depending on the type and severity of the renal abnormality. These tests included: repeated detailed ultrasonography, urinalysis and tests for blood urea nitrogen, serum creatinine and electrolytes. Renoscintigram and iv pyelography were also performed. Of the six children in whom pelvic dilatation was revealed, one patient with dilatation of 0.9 cm underwent micturation urethrocystography and no vesicourethro reflux was found.
Results There were 11 children (five boys and six girls) detected by ultrasonography as having a renal abnormality in this series. A further four children presented a falsepositive result, in which the initial sonograms showed a suspected renal abnormality but further ultrasonographic studies revealed no abnormality. The prevalence was 0.47% or 11 of the 2351 total population screened. Six (54.5%) of these showed slight pelvic dilatation ranging from 0.5 cm to 0.9 cm. Another 3 children (27.3%) showed a unilateral renal agenesis, and a further 2 (1 8.2%) showed a unilateral small kidney. As summarized in Table I , in the five patients with a small kidney or agenesis, urinalysis and determination of the serum creatinine and blood urea nitrogen did not reveal any abnormal findings. In these two patients with a unilateral small kidney, no scar formation was detected, and the distance of the major axis of the contralateral kidneys was 7.9 cm and 8.1 cm (mean
Ultrasonographic screeningfor renal abnormalities
ACTA PEDIATR 81 (1992)
327
Table 1. Description of the patients with agenesis and small-sized right (rt) and left (It) kidneys. Sex
Diagnosis
I . F (It) Agenesis 2. F (It) Agenesis 3. M (rt) Agenesis 4. M (rt) Small kidney 5. F (rt) Small kidney
Ultrasonography
DIP
Radionuclide renal imaging
(It) No detection (It) No detection (rt) N o detection Unilat. small rt kidney Unilat. small rt kidney
(It) No detection (It) N o detection (rt) No detection Unilat. small rt kidney Unilat. small rt kidney
(It) No uptake (It) N o uptake (rt) N o uptake (rt) Delayed peak (rt) Delayed peak
Serum creatinine Serum BUN (mmol/l) (mmol/l) Urinalysis 4.03 2.86 5.25 4.60 4.60
35.4 39.8 26.5 57.5 26.5
Negative Negative Negative Negative Negative
( f S D ) normal size for this study: 6.24 (f0.53 cm)) prenatal ultrasonographic examinations removing some indicating compensatory hypertrophy of the contrala- cases from our screening through earlier detection. teral kidney. Clinical features revealed that all 1 1 Prenatal ultrasonographic examinations are now routichildren were symptom-free and had no history of any nely performed in all maternity hospitals in Japan. The criteria for pelvic dilatation are not yet estabrenal disease in the past. Three of the six children with a slight pelvic dilatation lished, although definitions have been discussed (8). We were reexamined after an interval of more than six took a dilatation, of more than 0.5 cm as pelvic months. The degree of pelvic dilatation at follow-up dilatation. Pelvic dilatation as a sign of mild hydronephrevealed no change in the two children whose initial rosis revealed the highest incidence of abnormality in examinations showed a dilatation of 0.7 cm and 0.9 cm, our study. Modern ultrasonic equipment enables detecand complete spontaneous disappearance in the third tion of only slight pelvic dilataton, demonstrated in this study. The proportion of early renal abnormalities that child whose initial dilatation was 0.6 cm. require follow-up surgery is not yet known. Long-term follow-up studies are needed to clarify the natural histories of those found to have an early abnormality. Discussion Our results also show that a slight pelvic dilatation may Mass screening for proteinuria and hematuria in school be a spontaneously reversible phenomenon in infants. as children has been conducted since 1973 and is organized one case with 0.6 cm of dilatation demonstrated. The cost-benefit is an important aspect of mass by the Ministry of Education in Japan (1). The system has been working very efficiently and made possible screening. While we have demonstrated the efficacy of early detection of a variety of primary glomerular ultrasonography for the early detection and follow-up diseases. However, it is well known that congenital and of renal abnormalities, the inclusion of renal ultrasonofamilial rather than acquired renal diseases are leading graphic examinations in the regular health checks causes of chronic renal failure in children (2-4). There- nationwide is also related to non-pathological confore, a further target for screening will be a renal siderations such as cost effectiveness. Sheih et al. (9) structural abnormality such as congenital hydronephro- calculated the individual expense for each screening and this amounted to about $0.36 per child. They also sis or cystic disease. In Japan, regular health checks for infants and calculated the cost of surgical correction and the dialysis children are established by the Ministry of Health and fees. They stressed the high cost-efficacy of ultrasonoWelfare, so that most children received such a check at a graphic screening. In this study, the whole expense was local Health Center at age four months, one year, one- only the cost of depreciation of the ultrasonographic and-a-half years old, and at three years. Because an machine. The personnel were regular hospital staff and examiner using ultrasonography must see many chil- were free to this prospective study. The cost of the dren within a short time, three-year-old children who portable real-time ultrasound scanner we used was are capable of keeping steady their position during an about U$lOOOO. The service life of the machine is six examination are better candidates for our purpose than years. Our calculation of the individual expense was are one-and-a-half-year-olds. Epidemiological prenatal therefore about $0.66 per child. and neonatal studies have demonstrated the efficacy of We conclude that ultrasonography is an efficient an ultrasound screening program to detect renal abnor- initial screening tool for detecting various silent renal malities (4-7). structural abnormalities. With additional data, recomOur study demonstrated that ultrasonography can be mendation could be considered for including ultrasonoused for mass screenings of young children at a local graphy in the regular health check at health centers in health center and we found that 0.5% of the total Japan. population screened had a significant but silent renal abnormality. The prevalence of abnormalities in pre- Acknowledgement.-This study was supported in part by a grant from vious reports were relatively higher than in our study (4, the Ministry of Health and Welfare in Japan (as one of many research 5). This may be partly due to the effect of current projects for long-term management of pediatric renal diseases).
328
M Mihara el al.
References 1. Kitagawa T. Screening f m asymptomatic hematuria and protei-
nuria in school children. Relationship between clinical laboratory findings and glomerular pathology of prognosis. Acta Paediatr Jpn 1985;27:366-73 2. Elder JS;Duckett JW. Management of the fetus and neonate with hydronephrosis detected by prenatal ultrasonography. Pediatr An 1988;17:19-28 3. Chantler C, Carter JE, Bewick M, Counahan R, Cameron JS, Ogg CS, Williams DG, Winder E. Ten years' experience with chronic hemodialysis and renal transplantation in children. Arch Dis Child 1980;55:435-45 4. Broyer M. Donckerwolcke RA, Brunner FP, Brynger H, Jacobs C, Kramer P, Selwood NH, Wing AJ, Blake PH. Combined report on
ACTA PRDIATR 81 (1992)
regular dialysis and transplantation in children in Europe, 1980. Proc Eur Dial Transplant Assoc 1981;18:61-87 5. Steinhart JM, Kuhn JP, Eisenberg B, Vaughan RL, Maggioli AJ, Cozza TF. Ultrasound screening of healthy infants for urinary tract abnormalities. Pediatrics 1988;82:609-14 6. Helin I, Persson PH. Prenatal diagnosis of urinary tract abnormalities by ultrasound. Pediatrics 1986;78:879-83 7. Zaontz MR, Maizels M. Office urologic ultrasound in pediatric patients. Urol Clin North Am 1988;15:589-99 8. Tsai TC, Lee HC, Huang FY. The size of the renal pelvis on ultrasonography in children. J Clin Ultrasound 1989;17:647-51 9. Sheih CP, Liu MS, Hung CS, Yang KH, Chen WY, Lin CY. Renal abnormalities in schoolchildren. Pediatrics 198984:1086-90 Received Oct. 10, 1990. Accepted June 19, 1991
Ultrasonographic screening for renal abnormalities in three-year-old -children Masako Mihara, Yuhei Ito, Keiko Fukushima, Fumio Yamashita and Miwako Tsunosue' Department of Paediatrics and Child Health. Kurume University School of Medicine, Kurume and Kurume Healih Center. Kurume', Japan
Mihara M, Ito Y, Fukushima K, Yamashita F, Tsunosue M. Ultrasonographic screening for renal abnormalities in three-year-old children. Acta Piediatr 1992;81:326-8. Stockholm. ISSN 0803-5253 We report the results of ultrasonographic screening to determine the prevalenceof renal abnormalities in children. This study was conducted simultaneouslywith a regular health check using portable realtime ultrasound equipment, from July 1988 to June 1989. Of 2920 three-year-old children resident in Kurume City, 2351 (80.5O/") were screened. Abnormalities were detected in 1 1 (0.47%)of these, involving six cases of pelvic dilatation, three cases of unilateral renal agenesis, and two cases of a unilaterally small kidney. However, the simultaneous urinalysis of these 1 1 children did not disclose these abnormalities. Our results indicate that ultrasonbgraphy is an efficient tool for screening for a silent renal abnormality. 0 Renal abnormality, ultrasonographic screening M Mihara, Department of Pediatrics and Child Health, Kurume University School of Medicine, 67 Asahi Machi. Kurume City 830, Japan
The early detection of any renal abnormality is essential in pediatric nephrology. However, renal abnormalities always present non-specific symptoms or silence, especially among children, and it is difficult to detect an abnormality by routine urinalysis. To detect the prevalence of renal abnormalities, we established an efficient screening system for three-year-old children using ultrasonography. Nationwide regular health checks for three-year-old children are conducted at Japanese local health centers, and children at this age are able to hold steady their position for the duration of an ultrasonographic examination. For these reasons, these children were selected as subjects for this study.
Subjects and methods From July 1988 to June 1989, 2351 three-year-old children (80.5% of all three-year-old children in Kurume City) were screened at Kurume Health Center. A portable real-time ultrasound scanner (ALOKA, SSD21-DX) was used for the initial screening. Each child urinated before the ultrasonographic examination and was requested to lift up any clothing for examination in a ventral position on a bed, one after another. The probe, using a 5-MHz transducer, was placed on the back region and both kidneys were screened quickly, with each examination requiring 30 to 60 s. A routine urinalysis was also performed by spot urine collection. If a kidney abnormality was detected by our ultrasonographic screening, the examinee was referred to Kurume University Hospital for further checks and confirmation
of diagnosis. Further investigations were performed on a selective basis depending on the type and severity of the renal abnormality. These tests included: repeated detailed ultrasonography, urinalysis and tests for blood urea nitrogen, serum creatinine and electrolytes. Renoscintigram and iv pyelography were also performed. Of the six children in whom pelvic dilatation was revealed, one patient with dilatation of 0.9 cm underwent micturation urethrocystography and no vesicourethro reflux was found.
Results There were 11 children (five boys and six girls) detected by ultrasonography as having a renal abnormality in this series. A further four children presented a falsepositive result, in which the initial sonograms showed a suspected renal abnormality but further ultrasonographic studies revealed no abnormality. The prevalence was 0.47% or 11 of the 2351 total population screened. Six (54.5%) of these showed slight pelvic dilatation ranging from 0.5 cm to 0.9 cm. Another 3 children (27.3%) showed a unilateral renal agenesis, and a further 2 (1 8.2%) showed a unilateral small kidney. As summarized in Table I , in the five patients with a small kidney or agenesis, urinalysis and determination of the serum creatinine and blood urea nitrogen did not reveal any abnormal findings. In these two patients with a unilateral small kidney, no scar formation was detected, and the distance of the major axis of the contralateral kidneys was 7.9 cm and 8.1 cm (mean
Ultrasonographic screeningfor renal abnormalities
ACTA PEDIATR 81 (1992)
327
Table 1. Description of the patients with agenesis and small-sized right (rt) and left (It) kidneys. Sex
Diagnosis
I . F (It) Agenesis 2. F (It) Agenesis 3. M (rt) Agenesis 4. M (rt) Small kidney 5. F (rt) Small kidney
Ultrasonography
DIP
Radionuclide renal imaging
(It) No detection (It) No detection (rt) N o detection Unilat. small rt kidney Unilat. small rt kidney
(It) No detection (It) N o detection (rt) No detection Unilat. small rt kidney Unilat. small rt kidney
(It) No uptake (It) N o uptake (rt) N o uptake (rt) Delayed peak (rt) Delayed peak
Serum creatinine Serum BUN (mmol/l) (mmol/l) Urinalysis 4.03 2.86 5.25 4.60 4.60
35.4 39.8 26.5 57.5 26.5
Negative Negative Negative Negative Negative
( f S D ) normal size for this study: 6.24 (f0.53 cm)) prenatal ultrasonographic examinations removing some indicating compensatory hypertrophy of the contrala- cases from our screening through earlier detection. teral kidney. Clinical features revealed that all 1 1 Prenatal ultrasonographic examinations are now routichildren were symptom-free and had no history of any nely performed in all maternity hospitals in Japan. The criteria for pelvic dilatation are not yet estabrenal disease in the past. Three of the six children with a slight pelvic dilatation lished, although definitions have been discussed (8). We were reexamined after an interval of more than six took a dilatation, of more than 0.5 cm as pelvic months. The degree of pelvic dilatation at follow-up dilatation. Pelvic dilatation as a sign of mild hydronephrevealed no change in the two children whose initial rosis revealed the highest incidence of abnormality in examinations showed a dilatation of 0.7 cm and 0.9 cm, our study. Modern ultrasonic equipment enables detecand complete spontaneous disappearance in the third tion of only slight pelvic dilataton, demonstrated in this study. The proportion of early renal abnormalities that child whose initial dilatation was 0.6 cm. require follow-up surgery is not yet known. Long-term follow-up studies are needed to clarify the natural histories of those found to have an early abnormality. Discussion Our results also show that a slight pelvic dilatation may Mass screening for proteinuria and hematuria in school be a spontaneously reversible phenomenon in infants. as children has been conducted since 1973 and is organized one case with 0.6 cm of dilatation demonstrated. The cost-benefit is an important aspect of mass by the Ministry of Education in Japan (1). The system has been working very efficiently and made possible screening. While we have demonstrated the efficacy of early detection of a variety of primary glomerular ultrasonography for the early detection and follow-up diseases. However, it is well known that congenital and of renal abnormalities, the inclusion of renal ultrasonofamilial rather than acquired renal diseases are leading graphic examinations in the regular health checks causes of chronic renal failure in children (2-4). There- nationwide is also related to non-pathological confore, a further target for screening will be a renal siderations such as cost effectiveness. Sheih et al. (9) structural abnormality such as congenital hydronephro- calculated the individual expense for each screening and this amounted to about $0.36 per child. They also sis or cystic disease. In Japan, regular health checks for infants and calculated the cost of surgical correction and the dialysis children are established by the Ministry of Health and fees. They stressed the high cost-efficacy of ultrasonoWelfare, so that most children received such a check at a graphic screening. In this study, the whole expense was local Health Center at age four months, one year, one- only the cost of depreciation of the ultrasonographic and-a-half years old, and at three years. Because an machine. The personnel were regular hospital staff and examiner using ultrasonography must see many chil- were free to this prospective study. The cost of the dren within a short time, three-year-old children who portable real-time ultrasound scanner we used was are capable of keeping steady their position during an about U$lOOOO. The service life of the machine is six examination are better candidates for our purpose than years. Our calculation of the individual expense was are one-and-a-half-year-olds. Epidemiological prenatal therefore about $0.66 per child. and neonatal studies have demonstrated the efficacy of We conclude that ultrasonography is an efficient an ultrasound screening program to detect renal abnor- initial screening tool for detecting various silent renal malities (4-7). structural abnormalities. With additional data, recomOur study demonstrated that ultrasonography can be mendation could be considered for including ultrasonoused for mass screenings of young children at a local graphy in the regular health check at health centers in health center and we found that 0.5% of the total Japan. population screened had a significant but silent renal abnormality. The prevalence of abnormalities in pre- Acknowledgement.-This study was supported in part by a grant from vious reports were relatively higher than in our study (4, the Ministry of Health and Welfare in Japan (as one of many research 5). This may be partly due to the effect of current projects for long-term management of pediatric renal diseases).
328
M Mihara el al.
References 1. Kitagawa T. Screening f m asymptomatic hematuria and protei-
nuria in school children. Relationship between clinical laboratory findings and glomerular pathology of prognosis. Acta Paediatr Jpn 1985;27:366-73 2. Elder JS;Duckett JW. Management of the fetus and neonate with hydronephrosis detected by prenatal ultrasonography. Pediatr An 1988;17:19-28 3. Chantler C, Carter JE, Bewick M, Counahan R, Cameron JS, Ogg CS, Williams DG, Winder E. Ten years' experience with chronic hemodialysis and renal transplantation in children. Arch Dis Child 1980;55:435-45 4. Broyer M. Donckerwolcke RA, Brunner FP, Brynger H, Jacobs C, Kramer P, Selwood NH, Wing AJ, Blake PH. Combined report on
ACTA PRDIATR 81 (1992)
regular dialysis and transplantation in children in Europe, 1980. Proc Eur Dial Transplant Assoc 1981;18:61-87 5. Steinhart JM, Kuhn JP, Eisenberg B, Vaughan RL, Maggioli AJ, Cozza TF. Ultrasound screening of healthy infants for urinary tract abnormalities. Pediatrics 1988;82:609-14 6. Helin I, Persson PH. Prenatal diagnosis of urinary tract abnormalities by ultrasound. Pediatrics 1986;78:879-83 7. Zaontz MR, Maizels M. Office urologic ultrasound in pediatric patients. Urol Clin North Am 1988;15:589-99 8. Tsai TC, Lee HC, Huang FY. The size of the renal pelvis on ultrasonography in children. J Clin Ultrasound 1989;17:647-51 9. Sheih CP, Liu MS, Hung CS, Yang KH, Chen WY, Lin CY. Renal abnormalities in schoolchildren. Pediatrics 198984:1086-90 Received Oct. 10, 1990. Accepted June 19, 1991
