Hydrocele may occur after the placement of a double J-tube, but it is rare and is commonly caused by a blockage of the J-tube due to a urinary tract infection. Double J-tubes, or ureteral stents, are often placed after renal ureteral stone surgery or to relieve acute pyelonephrosis in order to support and drain the urine in the renal pelvis. Most patients do not develop hydronephrosis after placement of a double J-tube, but if a renal ureteral infection develops, the J-tube may become obstructed due to the growth of secretions. Infection is most common in patients who are old and frail and who have their own urinary tract infections. Due to recurrent urinary tract infections, bacterial secretions can grow along the distribution of the J-tubes, thus blocking them. If hydronephrosis still occurs after the placement of J-tube, you should go to the regular hospital in time for consultation and active treatment after clarifying the cause of the disease, so as to avoid the deterioration of the condition.