RD7.5 | Imaging in Pediatric Urinary Tract Infection — Summary & Reflection

KEY TAKEAWAYS

Imaging in Pediatric Urinary Tract Infection — Key Points

• Image selectively, by age and risk (NICE/ISPN protocols): younger children, febrile (upper-tract), atypical, or recurrent UTIs are imaged; a single typical lower-tract UTI in an older child often needs no extensive imaging.
• Three tools, three questions (ALARA — lead with the non-ionising test):
• Ultrasound (USG KUB) — first-line, anatomy: non-ionising; detects hydronephrosis, obstruction, structural anomaly, kidney size/scarring; the starting point for almost every child.
• MCUG/VCUG — reflux: ionising + catheter; diagnoses and grades vesicoureteric reflux (VUR) I–V and shows the urethra (posterior urethral valves in boys); reserved for defined indications.
• DMSA scintigraphy — cortex: ionising; photopenic cortical defects of acute pyelonephritis (acute scan) and permanent scarring (delayed scan); assesses differential function.
• VUR grading: I = ureter only; II = up to pelvis, no dilatation; III = mild–moderate dilatation with mild calyceal blunting; IV = moderate dilatation/tortuosity with calyceal blunting; V = gross dilatation/tortuosity with severe calyceal blunting (loss of papillary impressions). Higher grades = highest scarring risk.
• Management translation: normal study → reassure/safety-net; structural anomaly/obstruction → specialist referral; low-grade VUR (I–II) → often conservative ± prophylaxis (resolves with growth); high-grade VUR (IV–V) ± scarring → prophylaxis, urology referral, long-term renal follow-up; cortical scarring → lifelong surveillance for hypertension and CKD.
• Paediatric principle: children are more radiosensitive — start with ultrasound, reserve ionising MCUG/DMSA for clear indications, and re-image only when it changes management.

REFLECT

On your next paediatric posting, follow a child investigated after a UTI from the positive culture to the imaging decisions. Ask: was the choice to image (or not) made on the child's age and risk, or reflexively? Notice how often ultrasound alone answers the question, and how the team weighs the radiation and invasiveness of an MCUG or DMSA against what it will add. Then trace a reflux grade or a DMSA scar forward — did it actually change prophylaxis, referral, or follow-up? Seeing imaging as a way to protect the developing kidney, chosen one question at a time and with the lightest radiation footprint, is how the ALARA principle becomes a habit rather than a slogan.