Management of Asymptomatic Duplicated Collecting System in Adults
Primary Recommendation
An asymptomatic adult with a duplicated collecting system and no history of urinary tract issues requires no intervention, only surveillance imaging with annual renal ultrasound to monitor for complications. 1
Surveillance Protocol
Annual monitoring should include:
- Renal ultrasound annually to assess both kidneys for parenchymal changes, hydronephrosis, stones, or masses 1, 2
- Annual urinalysis to screen for infection, hematuria, and proteinuria 1, 2
- Urine culture only if urinalysis suggests infection (not routine screening in asymptomatic patients) 3, 2
The rationale for this conservative approach is that duplicated collecting systems affect 0.7-4% of the population and most remain asymptomatic throughout life 4, 5. Intervention is reserved for symptomatic patients or those who develop complications during surveillance.
When to Escalate Imaging
Advanced imaging with CT urography or MR urography should be obtained if:
- New hydronephrosis develops on surveillance ultrasound, suggesting obstruction 1
- Recurrent urinary tract infections occur despite appropriate treatment 1
- Hematuria is detected on urinalysis (requires upper tract imaging and cystoscopy) 3
- Complex anatomy requires surgical planning if intervention becomes necessary 1
MR urography is preferred over CT urography when radiation avoidance is desired, as it provides detailed morphologic and functional information about the collecting system 5. For patients with contraindications to both CT and MRI (such as renal insufficiency or metal implants), ultrasound combined with retrograde pyelograms can provide adequate evaluation 3.
Red Flags Requiring Intervention
Immediate evaluation and potential intervention are indicated for:
- Recurrent urinary tract infections (≥2 infections in 6 months or ≥3 in 12 months), which should prompt cystoscopy and upper tract imaging 3, 1
- Febrile UTI with inadequate response to antibiotics, requiring upper tract imaging to exclude obstruction or abscess 3
- Persistent flank pain suggesting obstruction or stone formation 4, 6
- Urinary incontinence or dribbling, which may indicate ectopic ureteral insertion requiring surgical correction 6, 7
- Deteriorating renal function on laboratory monitoring 3
Management of Complications
If recurrent UTIs develop:
- Obtain voiding cystourethrography (VCUG) to evaluate for vesicoureteral reflux, which occurs more frequently in duplicated systems 1
- Consider continuous antibiotic prophylaxis for documented reflux with recurrent infections 1
- Surgical options include endoscopic correction or ureteral reimplantation for persistent high-grade reflux or breakthrough infections despite prophylaxis 1
If a nonfunctioning upper pole develops:
- Robot-assisted laparoscopic heminephrectomy is the preferred surgical approach in adults, offering minimal morbidity and brief hospital stays 8
- This is typically reserved for symptomatic patients with documented nonfunctioning renal units causing recurrent infections or pain 8
Critical Pitfalls to Avoid
Common diagnostic errors include:
- Assuming hydronephrosis always indicates obstruction – it may represent reflux, bladder distention, or postobstructive dilation requiring bladder decompression and repeat imaging 1
- Treating asymptomatic bacteriuria – this should never be treated in neurogenic or non-neurogenic patients outside of pregnancy or pre-procedure settings, as it promotes antibiotic resistance 3
- Performing routine screening urine cultures in asymptomatic patients – this leads to unnecessary antibiotic use and resistant organisms 3
- Missing ectopic ureteral insertion – absence of hydronephrosis does not exclude ureteral pathology in duplicated systems 1
- Inadequate hydration before functional studies – dehydration may mask obstruction on imaging 1
Special Considerations
Duplicated systems in adults may present differently than in children:
- Most adult presentations are incidental findings or late diagnoses (cases reported as late as age 47) 4
- Males can present with duplicated systems and ureteroceles, though less common than females 4
- Ureteroceles may remain asymptomatic until adulthood and can be associated with recurrent UTIs 4
- Resource-limited settings require heightened awareness of unusual presentations and access to appropriate diagnostic tools 4
The key principle is that asymptomatic duplicated collecting systems require observation only, with intervention reserved for symptomatic complications that develop during surveillance.