IUS Steroid Failure and Colectomy Risk in Pediatric ASUC: Gastroenterology | August 2026

Acute severe ulcerative colitis (ASUC) in children requires rapid identification of intravenous corticosteroid failure to avoid delayed rescue therapy and colectomy. Intestinal ultrasound (IUS) offers a noninvasive, repeatable bedside assessment of bowel inflammation. This prospective multicenter study evaluated whether early and serial IUS can predict short-term treatment outcomes in pediatric ASUC.

Why was this study needed?

Around two-thirds of children with ASUC may require escalation beyond intravenous steroids.

Early prediction of steroid failure could accelerate rescue therapy.

Current decisions rely predominantly on clinical scores such as PUCAI.

IUS could provide an objective, radiation-free tool for real-time disease monitoring.

Results:

Among 60 children across 10 European centers, 65% were steroid nonresponders requiring infliximab, while 17% ultimately underwent colectomy.

Early IUS showed that greater colonic wall thickness (CWT), particularly >5 mm in the left lower quadrant, and increased vascularity predicted steroid resistance.

Repeat IUS at days 5–7 further predicted medical treatment failure and colectomy, with persistent CWT and high Milan Ultrasound Scores identifying high-risk patients.

Conversely, improvement in ultrasound parameters was associated with steroid-free remission at 8 weeks.

Clinical Impact:

IUS could become a valuable bedside decision-making tool in pediatric ASUC, complementing PUCAI by objectively assessing bowel inflammation. Early and serial scans may identify steroid nonresponders sooner, allowing timely escalation to infliximab or other rescue therapies while recognizing patients at increased risk of colectomy.

Bottom Line:

Early and serial intestinal ultrasound can predict steroid resistance, medical treatment failure, and colectomy risk in children with acute severe UC. IUS may provide a practical, noninvasive tool for earlier treatment escalation and tighter monitoring of pediatric ASUC.