Clinical and imaging features of intermittent hydronephrosis in children with ureteropelvic junction obstruction

Abstract

Objective Hydronephrosis due to ureteropelvic junction obstruction (UPJO) is characterized by long-term stability or progressive exacerbation in children. However, a few of them have intermittent hydronephrosis. The clinical and imaging characteristics of intermittent hydronephrosis were analyzed for 37 UPJO children. Methods Retrospective analysis was performed for 37 hospitalized children aged 3-14 years with intermittent hydronephrosis from July 2013 to December 2017. Routine liver & renal function tests, urinary tract ultrasound and diuresis renogram were performed. The clinical data were collected and their clinical symptoms and imaging abnormalities summarized. Results Among them, 4 children were lost to follow-ups. All presented with flank abdominal pains typically lasting <2 days. Acute episode generally resolved spontaneously and was followed by a pain-free interval of 7 days to 4 months. Predisposing factors included greater water intake and vigorous exercises. Twenty-three (69.7%) children had nausea and vomiting. Ultrasound examination hinted at an obvious dilatation of renal pelvis. During convalescence, 63.6% children demonstrated renal pelvic wall thickening on ultrasonography. This findings persisted for 6 to 9 days and then disappeared during symptom-free stage. After ureteropelvoplasty, only 1 case relapsed postoperatively. The presence of UPJO was confirmed by intraoperative findings and pathological examination. Six (18.2%) patients had a fibroepithelial polyp of ureter. Conclusions The essentials of diagnosing UPJO inducing intermittent hydronephrosis are differentiating syndrome, detailed history-taking and serial imaging studies during the episodes of abdominal pain. A thickened renal pelvic wall during convalescence is an important ultrasonic sign of intermittent hydronephrosis. Key words: Hydronephrosis; Pyeloplasty; Ureteropelvic junction obstruction