View source for Main article- Ureteral stent difficulties

Ureteral stent symptoms may include:

1. Hematuria - Stents can cause blood to appear in the urine at various times. Usually, physical activity of one kind or other results in movement of the stent inside the body. This can give rise to blood in the urine. Pain may be felt in the back (loin), bladder area, groin, penis in men or urethra in women, and sometimes the testicles. The discomfort or pain may be more noticeable after physical activities and after passing urine.

2. Bladder spasms - The stent can rub and irritate the lining of the bladder, making it necessary to pass urine more frequently during the day and at night. These symptoms can occasionally be improved by medication.

3. Incontinence - Rarely, a stent may cause such bladder spasms leading to urinary leakage. This can usually be controlled with oral medications or with stent removal.

4. Stent migration – Stents may move from their intended positions to other parts of the urinary tract, causing pain or incontinence.

5. Infection – As stents are foreign bodies, bacteria can attach to their surface and become protected by a layer of slime known as a “biofilm.” These bacteria may then be released into the urine, causing infection and fever. These infections may temporarily be cleared with antibiotics, but usually recur 2-3 weeks after antibiotics as the antibiotics are unable to penetrate the biofilm.

6. Encrustation - Stents may be forgotten by patients and their care-givers. Over time, they can become coated with urinary salts and minerals and eventually become one very large calcified stone. This may lead to chronic obstruction, pain, chronic infections, or even complete atrophy (death) of that kidney. Typically, 2-3 procedures are necessary to remove these calcified stents.

Source - [http://urology.ufl.edu/MIS/stone/ureteroscopy.php Stent problems]