A 3-year-old girl is evaluated for her second febrile UTI. Urine culture grows E. coli >100,000 CFU/mL. Renal ultrasound shows left-sided hydronephrosis. DMSA scan performed 3 months after the infection shows a cortical scar in the upper pole of the left kidney. What is the most likely underlying structural abnormality?
- A Posterior urethral valves
- B Ureteropelvic junction (UPJ) obstruction
- C Neurogenic bladder
- D Vesicoureteral reflux (VUR) ✓
Explanation
Vesicoureteral reflux (VUR) is the most common uropathy associated with recurrent febrile UTI and renal scarring in children. During voiding, urine refluxes from the bladder into the ureter and renal pelvis, carrying bacteria into the kidney and causing pyelonephritis and renal scarring (reflux nephropathy). Cortical scarring on DMSA is the hallmark of reflux nephropathy. Hydronephrosis from VUR is dilating. UPJ obstruction causes hydronephrosis without UTI predisposition (unless complicated). Posterior urethral valves affect males only and cause bilateral hydronephrosis. VUR is graded I–V on voiding cystourethrogram (VCUG).
Reference: Ghai Essential Pediatrics, 10th ed.
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Written and medically reviewed by the StethoPrep medical team.