During cancer treatment it is not unusual for the ureter, the narrow tube that carries urine from the kidney to the bladder, to become narrowed or compressed. A tumour may press on it directly, abdominal or pelvic lymph nodes may enlarge, or scarring after surgery or fibrosis after radiotherapy may close it in. To keep urine draining and prevent the kidney from swelling (hydronephrosis), a thin flexible tube is placed inside the ureter. This is a ureteral stent, also called a double-J or DJ stent because both ends curl like a pigtail. Stents are usually made of coloured polymer, and because they stiffen and collect mineral deposits over time, they are typically exchanged every few months.
While a stent is in place, something unfamiliar may appear in the urine, and there are several possibilities. The first is the stent itself, or part of it. A stent is a soft coloured tube that can look like a long, pliable rubber band, and if the curl at the bladder end straightens, the stent can slip downward and pass out through the urethra (stent migration). The second is the thin string, or tether, that is sometimes left running out of the body after an exchange; when a tether has been left in place, it may come away first. The third is a blood clot or a strand of fibrin, which can appear as red or brown fragments for some weeks after a procedure. The fourth is a piece of the mineral crust (encrustation) that builds up on the stent surface, and less commonly it may be a fragment of mucosal tissue.
It is difficult to identify any of these by sight alone. That is why, overnight, the more useful question is not what the object was but whether urine is still draining. If the stent was on one side only and the other kidney works normally, the situation is unlikely to become dangerous within a few hours. If stents were placed on both sides, if only one functioning kidney remains, or if kidney function was already reduced, there is less room to wait.
The signs worth watching overnight are fairly clear. Passing very little urine or none at all for several hours, new flank or back pain or pain that escalates quickly, a fever of 38°C or higher or shaking chills, vomiting that makes it impossible to keep fluids down, or heavily bloodstained urine with ongoing clots all justify a trip to the emergency department rather than waiting for clinic hours. Fever deserves particular weight, because an infection behind an obstructed kidney can worsen rapidly. If there is no pain and no fever and urine output looks much as usual, contacting the clinic when it opens is generally reasonable.
Do not discard whatever came out. Keep it in a clean bag or container, photograph it next to a ruler so its length, thickness and colour are recorded, and note the time it appeared along with urine output and any pain since. This makes the next day's explanation far quicker.
Sometimes the local term for the device does not register with whoever answers the phone or greets you at the emergency department. Saying "ureteral stent", "double-J stent", or "a tube placed from the kidney to the bladder" usually gets the message across. It also helps to state when it was placed or exchanged, whether it is one side or both, which hospital and which department did it (urology, or interventional radiology), whether there is also a tube in the back (percutaneous nephrostomy), and where cancer treatment is being given. Having a photograph of the procedure report or discharge summary on hand is the fastest way to convey all of this.
The next day, contact the department that performed the procedure first. They will usually check urine output and symptoms, then use ultrasound, a plain abdominal X-ray, or CT to confirm whether the stent is still in position and whether the kidney is swollen. If the stent has genuinely come out, a repeat placement is scheduled; if infection or reduced kidney function is present as well, the order of steps may change.
This article is general information and does not replace diagnosis or treatment for any individual. Symptoms and the right response differ from person to person, so please discuss any decision or action with your own medical team.