الفهرس 
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Abstract
Congenital urinary tract anomalies are relatively frequent and may be found in about 3% to 4% of the population (Kim et al., 2009). Also they account for 20 to 30 percent of all anomalies identified in the prenatal period (Dugoff, 2002).
Many cases of renal insufficiency in childhood are attributed to congenital anomalies of the kidneys and urinary tract (Kim et al., 2009). Also, congenital anomalies of the urinary tract are well known causes of urinary tract infections (UTIs) in children (Ahmadzadeh and Askarpour, 2007). UTIs have been considered an important risk factor for the development of renal insufficiency or end-stage renal disease in children (Elder, 2007).
Therefore, early diagnosis of congenital anomalies of the urinary tract is crucial, as potential targeted therapy (either surgical or conservative) might prevent irreversible damage of the renal parenchyma (Halek et al., 2010).
The postnatal ultrasound screening of the urinary system is a reliable, cheap and non-invasive method. It can be performed in many local hospitals as a primary screening tool for the newborn. Through its help, many subclinical renal abnormalities will be diagnosed early (Chein et al., 1999).
Our study was done to detect abnormalities of the kidney and urinary tract in apparently healthy newborns by postnatal renal ultrasound screening, also to determine the accuracy of prenatal ultrasound in excluding renal abnormalities, and to detect UTI in those with detected abnormalities.
In our study, renal ultrasound screening was performed on 300 apparently healthy newborns, who fulfilled the following criteria: a- inclusion criteria: gestational age 35 weeks, birth weight 1.800 kg, and postnatal age >3 and < 7 days, and b- exclusion criteria: sick neonates, neonates with congenital abnormalities including those on prenatal ultrasound.
The results of our study revealed that the total incidence of renal abnormalities on initial renal ultrasound screening is 5.3% (16/300) with male predominance, 10 males and 6 females (male : female = 5:3). One case out of the sixteen cases found on our initial ultrasound screening, was right renal agenesis with an incidence of 1/300 (0.3%). The other 15 cases was renal pelvis dilatation (RPD) with an incidence of 15/300 (5%). 12 cases (4%) with mild (anteroposterior diameter APD of 5-9.9 mm), 3 cases (1%) with moderate (APD 10-14.9 mm), and no case of severe renal pelvis dilatation (APD 15 mm), also there were male predominance, 9 males and 6 females (male : female = 3:2).
In our study, we set a protocol for follow up of cases of renal pelvis dilatation, and were as follows:
– APD <5 mm, no special measures, routine care.
– APD ≥5 mm <10 mm, detailed ultrasound examination of the urinary tract by a pediatric radiologist after 1– 2 months, an individualized approach based on the findings.
– APD ≥10 mm, detailed ultrasound examination of the urinary tract by a pediatric radiologist, an individualized diagnostic and therapeutic approach, surveillance by a pediatric nephrologist.
All newborns with APD 10, received cephalexin 10 mg/kg/day as a single dose.
Further diagnostic and therapeutic procedures:
– If regression occurred, the child was no longer followed up.
– If isolated unchanged mild RPD (APD < 10 mm) was detected, US follow-up was performed.
– In cases of persistent significant dilatation or progression
(APD ≥ 10 mm), ureteral dilatation, reduction of the renal parenchyma, or clinically significant urinary tract infection, other investigations were added [voiding cystourethrography (VCUG) or renal scintigraphy].
Follow up of renal pelvis dilatation revealed resolution of most of cases within the 6 month follow up, and specific final diagnosis was reached for 3 cases. In follow of the 15 cases of renal pelvis dilatation, 2 cases were lost to follow up, and in 2 cases, it was still too short to complete follow up. Eleven cases out of the 15 cases complete the follow up. Eight cases of them (73%) showed resolution within the 6 months follow up period, in 5 cases; resolution was at 1st month follow up, in 1 case at 4th month follow up, and in 2 cases at 6th month follow up. In one case with mild pelvis dilatation, there was persistence of renal pelvis dilatation at 6th month follow up and so VCUG was done and right vesicoureteral reflux (VUR) grade II was diagnosed. In one case with moderate renal pelvis dilatation, also, there was persistence of renal pelvis dilatation at 6th month, so VCUG was done and left VUR grade II was diagnosed. In one case with moderate pelvis dilatation, follow up at 1st month revealed progressive dilatation of renal pelvis so 99mTc-Diethylenetriaminepentaacetate (DTPA) was done and ureteropelvic junction obstruction (UPJO) was diagnosed. So the follow up of renal pelvis dilatation showed 2 cases of VUR (both grade II) with an incidence of 0.66% and one case of UPJO with an incidence of 0.33%.
In our study we screened those with congenital abnormalities for UTI using urinalysis of urine sample collected by urine bag at time of detection of congenital anomalies and after 2 weeks. In the urinalysis we looked for pus cells and pyuria was defined as > 5/HPF. Also we informed the parents about the symptoms and signs of UTI. In all cases there was no pyuria. In one case with renal pelvis dilatation, UTI was suspected clinically during the period of follow up, urine analysis was negative, culture of urine sample collected by catheter was done, and no organism was grown.
Our conclusion is that congenital renal abnormalities are not uncommon in apparently healthy newborns and can be missed during the prenatal ultrasound screening, Postnatal ultrasound renal screening is reliable, cheap, and non-invasive method, enabling the early detection of these subclinical abnormalities and hence the early management. Also, we concluded that mild renal pelvis dilatation detected postnatally is usually a benign condition, and most regress during six months follow up by ultrasound. Also, we concluded that prophylactic antibiotics may not be needed for mild renal pelvis dilatation detected postnatally.
We recommend postnatal renal ultrasound screening for all newborns after 3 days of age. Also, we recommend only ultrasound follow up for mild renal pelvis dilatation detected postnatally as it is usually a benign condition, and other diagnostic imaging studies are reserved for persistence of dilatation more than 6 months follow up. Prophylactic antibiotics may not be needed for mild renal pelvis dilatation detected postnatally, however, further studies are needed to determine which cases with other renal abnormalities are in need of prophylactic antibiotics, using large sample study and control groups.