My son underwent nephrectomy(left) in June 2010 ((he was 6 yrs) due to congenital obstruction between his blader and ureter detected late. After the surgery, now after 2 years he is again found frequently urinating and sonography says mild hydronephrosis and upper hydroureter in the right kidney. what may be the possible reasons. In 2010 his renal scan said functioning of right kidney to be 92%.
Hello, Thanks for posting your query. Hy Chat Doctor.  It can be due to lower urinary tract infection which may ascend to kidneys causing frequency of urine and distension of kidney/ureter. Stone in ureter can also cause distension of ureter and kidney but would have been detected on sonography. As your child has had surgery for congenital abnormality, he is at higher risk of UTI and obstruction by post-surgical strictures. Give him cranberry juice which may cure and prevent Otis. Get his labs done, urinalysis, urine culture and dye scan.UTI can be treated effectively with antibiotics after urine culture results. Hope it helps. Take Care!