Even when clinical remission is achieved with medication, paediatric ulcerative colitis (UC) is characterised by poor sustained remission rates and frequent disease progression. Moderate-to-severe endoscopic activity is a risk factor for relapse, but there is little prospective data in children on early mucosal repair or the persistence of inflammation after remission. The goal was to see if considerable inflammation is frequent after clinical remission and if so, if so, whether it may explain the high recurrence incidence in juvenile UC. Pediatric UC patients in clinical remission, defined as a PUCAI score of 10, were evaluated for mucosal repair by endoscopy 3 to 5 months after remission was verified. Patients who were symptomatic before to sigmoidoscopy were eliminated. Sustained remission was evaluated retrospectively after an 18-month follow-up period. Forty-two children were tested, with 28 of them in continuous clinical remission at the time of the sigmoidoscopy. Mayo 0 was found in 12/28 endoscopies, Mayo 1 in 2/28, and Mayo 2 to 3 in 14/28 endoscopies. Remission was maintained in 6/12 of patients with a Mayo score of 0 to 1 vs 2/11 of patients with a Mayo score of 2 and 3.

Over half of the children evaluated for mucosal healing 3 to 5 months following clinical remission have endoscopic illness, predominantly moderate-to-severe Mayo 2 to 3 inflammation, which has been linked to reduced maintained remission.

Reference: https://journals.lww.com/jpgn/Abstract/2021/04000/Moderate_to_severe_Endoscopic_Inflammation_is.18.aspx