A 3-year-old girl presents with high-grade fever, dysuria and vomiting. Urine dipstick shows leucocyte esterase positive and nitrite positive. Urine culture grows >100,000 CFU/mL of E. coli. DMSA scan at 6 months follow-up shows permanent cortical scar. This finding indicates:

• A Ongoing active infection
• B Post-infectious renal scarring (reflux nephropathy) ✓
• C Wilms tumor
• D Medullary nephrocalcinosis

Explanation

DMSA (dimercaptosuccinic acid) scintigraphy is the gold standard for detecting renal cortical scarring. Permanent scars on DMSA at 6 months post-UTI indicate reflux nephropathy, most commonly associated with vesicoureteral reflux (VUR) that allows infected urine to reach the renal parenchyma. This is distinct from acute photopenic defects on DMSA during active infection (acute pyelonephritis), which may resolve. Persistent scars are associated with hypertension and CKD in later life and warrant follow-up of blood pressure and renal function.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.