hemorrhage after percutaneous nephrolithotomy ( pcnl ) is a significant complication that occurs in a small percentage of cases . however , arterial injuries sometimes require transarterial embolization to control the refractory bleeding . in patient presenting with refractory bleeding , pseudoaneurysm formation is the most common cause with a reported incidence of 0.6 - 1% . we report a case of early erosion of an embolization coil from the renal vasculature into the urinary collecting system causing urinary tract obstruction and urosepsis . a 23-year - old male underwent left urs and pcnl for a left upper ureteric calculus and a 2.5-cm lower pole renal calculus in a community hospital in december , 2010 . one week after nephrostomy tube removal , the patient experienced gross hematuria with clot retention . the patient underwent endoscopic bladder clot evacuation and dj stent removal in the same hospital . two weeks later , again he developed gross hematuria with fever and a significant decrease in hematocrit . after resuscitation the patient was referred to our centre . on angiography , there was a pseudoaneurysm in the lower segmental renal artery . after 3 months of embolization , the patient presented with high - grade fever , left flank pain and burning micturiton . on x - ray kub 2 coils were seen in left renal area , whereas 1 coil was seen in l3 transverse process area . axial noncontrast and contrast - enhanced ct images showed left hydronephrosis with dilated upper ureter and an embolization coil in the upper ureter [ figure 1 ] . x ray kub shows 2 coils in left renal area , 1 coil in l3 transverse process area . ct urogram shows left hydronephrosis with dilated upper ureter and 2 coils in left kidney & 1 coil in upper ureter in 1975 , angioembolization for renal pseudoaneurysm was reported in a human patient when an autologous blood clot was used to embolize a bleeding pseudoaneurysm as a temporary measure before nephrectomy . we found only three case reports in which embolization coil migrated to the collecting system.[810 ] in all these case reports the coil eroded after 1 year following embolization . all the three patients presented with hematuria and renal colic . in our case , patient presented early ( 3 months ) with complaints of renal colic and persistent fever after coil embolization . hypothetically three mechanisms of coil erosion have been proposed . first , the diameter of arteriocaliceal communication might be larger than the embolization coil , and the coil gets extruded through the communication soon after placement . second , the arteriocaliceal communication could get dilated over time because of inflammation due to infection or the constant irritation from the indwelling coil itself , leading to eventual erosion into the collecting system . finally , rupture of the weakened wall of a pseudoaneurysm exposed to high arterial pressure may lead to erosion . according to the first hypothesis , if the arteriocaliceal communication was larger than the embolization coil than all three coils would have extruded through the communication and gross hematuria would have reappeared . the third mechanism would have lead to massive hematuria in addition to the coil migration . in this case the patient presented with high - grade fever and left flank pain but not hematuria . therefore in this case the second mechanism seems to be the most likely cause of erosion of the embolization coil . one of the important but rare causes of urinary tract obstruction is the migration of embolization coil into urinary collecting system .
refractory bleeding following percutaneous nephrolithotomy ( pcnl ) is mainly due to formation of pseudoaneurysm . 
 transarterial embolization is required to control the bleeding in such cases . 
 we report a case of post - pcnl hematuria in whom angioembolization was done . 
 an early erosion of the embolization coil from the renal vasculature into the urinary collecting system occurred , causing urinary tract obstruction and urinary tract infection ( uti ) . 
 the coil was retrieved ureteroscopically after control of uti with antibiotics . 
 migration of embolization coil into urinary collecting system is a rare but important cause of urinary tract obstruction . 
 the treating physician as well as the patient should be aware of this complication .