Renal stents.

Ureteral stents are used to promote drainage of the upper urinary tract. Although stents are used to relieve ureteral obstruction from any cause, they are most often placed due to obstruction by renal calculi. Ureteral stents may be placed emergently if obstruction is complicated by azotemia, infection, obstruction of a solitary kidney, or pain refractory to analgesia. Complications of renal stents include encrustation, migration, infection, pain and discomfort, urinary reflux, failure to properly drain, and hematuria. Serious complications are rare but include upward migration and infection leading to septic shock. Frequent complications include pain and discomfort and microscopic hematuria. Gross hematuria may occur as a result of erosion of a segment of the urinary tract. Emergency physicians can be expected to encounter patients with these complications of ureteral stents because of the widespread use of this prosthetic device.