Bladder Stone
A 45-year-old woman presented with a complaint of lower abdominal heaviness, increased frequency of urination, and change in color of urine, as well as nausea, vomiting, and fever for 1 week.
She had a past history of repeated kidney stones. A left stent was placed 2 years prior. The patient was lost to follow-up.
Her vitals included blood pressure of 125/84 mm Hg, respiration of 18 bpm, heart rate of 82 bpm and a T of 36.1.
Physical examination was unremarkable in her head and neck. There was clear bilateral to auscultation in the chest and normal heart sounds with no murmurs. An abdominal exam was lax, resonant with left CVA tenderness, lower abdominal tenderness, and no rebound or guarding.
Her labs were normal apart from the urinarlysis which showed a urinary tract infection (UTI). Abdominal x-ray (Figure 1) showed a large stone in the bladder and a coiled stent. The CT scan (Figure 2) found an irregular contour of left kidney with hydronephrosis. Large calculus filling the urinary bladder formed around a coiled uretral stent (Figure 3).
The recent increase in usage of ureteral stents in the management of a variety of urinary tract disease processes mandate familiarity with these devices, their consequences and their potential complications, which at times can be devastating. Risk factors should be minimized with high fluid intake, timely evaluation of clinical complaints and aggressive treatment of documented infection.1
Consequences and complications of indwelling ureteral stents have been reported: urinary tract infection, malposition and migration, encrustation stent fracture, ureteral erosion or fistulisation and the forgotten stent.
Migration of the stent within the urinary tract may occur as peristalsis may discharge a stent from the ureter either upward or downward into the urinary bladder.2
Encrustation, even of both extremities of the stent is a frequent complication. The presence of the stent provides a framework for the deposition of urine constituents. Encrustation is one of the major indications for prophylactic exchange of ureteral stents.3
Neither the urinary environment nor the stent placed within it is stable for long periods of time. The prevalence of all consequences and complications increases the longer a stent remains in place. Occasionally, stents are "forgotten," adding to the complications occurring as a result of the longer indwelling times.4
Severe encrustation and stone formation on indwelling ureteral stents in 2 patients with a lithogenic history has been reported.5 ■
References:
1. Dyer RB, Chen MY, Zagoria RJ, et al. Complications of ureteral stent placement. Radiographic. 2002;22(5):1005-1022.
2. Gibbons WS, Barry JM, Hefty TR, et al. Complications of ureteral stenting. Appl Rdio. 1990;35-423.
3. Cox J, Millington R, Hukins D, Sutton T. Resistance of conformable indwelling urinary catheters to encrustation. Artificial Cells, Blood Substitutes and Biotechnology. 1989;17(4):429-435.
4. Ivil KG, Suresh G. Incorporation of forgotten stent into the ureteral wall. J Urol. 2001;165(6 Pt 1):1991-1992.
5. Gotwald R, Peschel F, Frauscher F, et al. Indwelling ureteral stent fragmentation with severe encrustation and stone formation. J Urol. 2005;162(3 Pt 1):788.