TOACS FCPS Station · IVU: Duplex Ureter (Duplicated Collecting System)

📷 Intravenous Urogram (IVU)

IVU showing duplicated ureter (duplex collecting system) with upper pole moiety

Figure 1 · Intravenous urogram · Duplex Ureter – Duplicated Collecting System

🔍 Key radiographic features:

✓ Two separate ureters on the affected side
✓ Upper pole moiety – smaller, higher, often has delayed excretion and hydronephrosis
✓ Lower pole moiety – larger, lower, may show reflux or obstruction
✓ Weigert-Meyer rule: Upper pole ureter inserts inferomedially (ectopic, often obstructed); lower pole ureter inserts superolaterally (often reflux)
✓ Ureterocele – cystic dilation of the upper pole ureter (if present)

📋 Clinical scenario (examiner prompt)

A 6‑year‑old girl with a history of recurrent urinary tract infections and daytime wetting undergoes an intravenous urogram (IVU). The image shows two ureters on the right side, with the upper pole moiety showing hydronephrosis and delayed excretion.

Recurrent UTIs Two ureters Upper pole hydronephrosis Delayed excretion

🧑‍⚕️ Examiner tasks · TOACS

1. Identify the diagnosis from the IVU and clinical context.

2. Describe the X‑ray findings (duplex ureter, upper pole hydronephrosis).

3. Explain the Weigert‑Meyer rule and its clinical significance.

4. Discuss associated anomalies and management (ectopic ureter, ureterocele, reflux).

⚠️ Key concept: A duplex kidney (duplicated collecting system) is the most common congenital urinary tract anomaly. The Weigert‑Meyer rule states that the upper pole ureter inserts inferomedially (ectopic, often obstructed by ureterocele), while the lower pole ureter inserts superolaterally (often associated with vesicoureteral reflux).

🎯 Expected answers (for examiners)

• Diagnosis: Duplex kidney (duplicated collecting system) with upper pole hydronephrosis
• X‑ray findings: Two ureters, upper pole moiety hydronephrosis, delayed excretion
• Weigert‑Meyer rule: Upper pole ureter → inferomedial insertion (ectopic/obstructed); lower pole ureter → superolateral insertion (reflux)
• Management: VCUG (rule out VUR), MAG3 scan (differential function), upper pole heminephrectomy if non-functioning

⚡ Quick FCPS‑style MCQ

According to the Weigert‑Meyer rule in a duplex kidney, the upper pole ureter:

A. Inserts inferomedially and is associated with obstruction B. Inserts superolaterally and is associated with reflux C. Has no clinical significance D. Is always associated with renal agenesis

Feature	Upper Pole	Lower Pole
Ureter insertion	Inferomedial (ectopic)	Superolateral
Common problem	Obstruction (ureterocele)	Reflux (VUR)
Function	Often poor	Usually good
Presentation	UTI, incontinence	UTI, pyelonephritis

🩻 TOACS FCPS Station · IVU: Duplex Ureter (Duplicated Collecting System)

📷 Intravenous Urogram (IVU)

🧑‍⚕️ Examiner tasks · TOACS

📌 Topic summary ·