[Dodatkowa tętnica nerkowa przyczyną skrajnego wodonercza u 5-letniego chłopca].

: Hydronephrosis in children is most often due to an intrinsic ureteropelvic junction obstruction or by compression on ureter by accessory renal artery coming from the aorta to the lower pole of the kidney. AIM: The aim of study was to present a case with a late onset of hydronephrosis caused by accessory renal artery. CASE REPORT: 5-year old boy with a mild pyelectasia during first 10 months of age was admitted to hospital because of abdominal pain and vomiting. Abdominal ultrasound revealed a marked dilatation of the right pelvicalyceal system with renal pelvis measuring 23 mm in anterior-posterior (ap) diameter, enlargement of calyces to 10 mm and narrowed cortex to 5 mm. Dynamic scintigraphy (99mTc-EC) showed right-sided hydronephrosis with decreased isotope intake up to 31%, prolonged time of tissue perfusion and signs of ureteropelvic junction obstruction. Computed tomography urography with vascular option revealed right kidney length of 116 mm with narrow cortex, and dilated renal pelvis up to 53x52x28 (ap) mm and dilated calyces up to 16 mm. Apart from dilated collecting system, the computed tomography showed two renal arteries: normal artery coming from the aorta at the L1 level and the accessory renal artery, which originated from the aorta to the lower pole of the kidney at the L2/L3 level. The accessory renal artery compressed on the ureter causing hydronephrosis. The pyeloplasty modo Hynes-Anderson was performed. After 3 months an abdominal ultrasound revealed the right kidney of 89 mm in length with only moderate hydronephrosis: dilatation of renal pelvis up to 15-18 mm and calyces up to 7-8 mm. Scintigraphy showed isotope intake 48%. CONCLUSIONS: Hydronephrosis caused by accessory renal artery can be asymptomatic, with mild dilatation of pyelocalyceal system seen on abdominal ultrasonography. The first clinical symptoms may occur after several years and be associated with large hydronephrosis.