A 42-year-old woman with a history of recurrent urinary tract infections undergoes imaging for suspected anatomical abnormality. Contrast-enhanced CT shows a duplicated collecting system on the right side with the upper pole ureter crossing medially and inserting ectopically into the bladder trigone. The lower pole ureter inserts normally at the trigone. The patient is asymptomatic. What is the most appropriate next step?

Explanation

## Anatomical Background: Duplicated Collecting System **Key Point:** Complete ureteral duplication occurs in ~1% of the population. The **Weigert-Meyer rule** states: the upper pole ureter is located laterally and inserts ectopically (below the normal insertion site); the lower pole ureter inserts medially and normally. **Mnemonic: WEIGERT-MEYER RULE** — **W**eaker (upper pole) **E**ctopic **I**nsertion, **G**oes **E**ven **R**arer (lower pole) **T**ypical. ## Clinical Significance of Ectopic Insertion Ectopic ureteral insertion into the bladder trigone (or beyond, into urethra, vagina, or rectum) predisposes to: - Vesicoureteral reflux (VUR) — particularly in the ectopic upper pole ureter - Recurrent UTIs - Hydroureteronephrosis of the upper pole - Urinary incontinence (if insertion distal to sphincter) ## Why VCUG is the Next Step 1. **Diagnostic confirmation:** VCUG directly visualizes the duplicated system and grades any reflux present (Grades I–V). 2. **Risk stratification:** Reflux severity determines whether conservative management or intervention is appropriate. 3. **Guides management:** - No reflux + asymptomatic → observation - Reflux present → prophylactic antibiotics ± surgical intervention ## Management Algorithm ```mermaid flowchart TD A[Duplicated collecting system diagnosed]:::outcome --> B[Perform VCUG]:::action B --> C{VUR present?}:::decision C -->|No reflux| D[Asymptomatic + normal renal function]:::decision C -->|Grade I-II reflux| E[Prophylactic antibiotics + follow-up imaging]:::action C -->|Grade III-V reflux| F[Consider upper pole hemiureterectomy]:::action D -->|Yes| G[Observation, routine imaging]:::action D -->|Recurrent UTI/obstruction| H[Hemiureterectomy]:::action ``` **Clinical Pearl:** The presence of ectopic insertion alone does not mandate surgery. The key decision point is whether reflux is present and its grade. Many patients with asymptomatic duplicated systems and no reflux require only observation. **High-Yield:** Hemiureterectomy (removal of upper pole ureter and corresponding renal moiety) is indicated only if: - High-grade reflux (Grade III–V) refractory to medical management - Recurrent symptomatic UTIs despite prophylaxis - Obstructive uropathy with deteriorating renal function - Ectopic insertion causing incontinence Not for asymptomatic patients without reflux.