title: Atypical disease phenotypes in pediatric ulcerative colitis: 5-year analyses of the EUROKIDS Registry.
abstract: BACKGROUND
  Definitive diagnosis of pediatric ulcerative colitis (UC) may be particularly challenging since isolated colitis with overlapping features is common in pediatric Crohn's disease (CD), while atypical phenotypes of UC are not uncommon. The Paris classification allows more accurate phenotyping of atypical inflammatory bowel disease (IBD) patients. Our aim was to identify the prevalence of atypical disease patterns in new-onset pediatric UC using the Paris classification.
  
  
  METHODS
  Information was collected from the EUROKIDS Registry, an inception cohort of untreated pediatric IBD patients undergoing evaluation at diagnosis. Patients with IBD-unclassified were excluded. Patients with isolated Crohn's colitis served as a control group.
  
  
  RESULTS
  Data from 898 pediatric patients (643 UC, 255 CD colitis) were included. Extensive or pancolitis was present in 77% of UC patients and macroscopic rectal sparing in 5%. Rectal sparing was inversely associated with age (mean age with rectal sparing 9.9 years vs. 11.8 without; P = 0.02). Upper gastrointestinal (UGI) involvement occurred in 4% of patients. Erosions in the stomach were present in 3.1% of children, but frank ulcerations in 0.4%; 0.8% of children had erosions or ulcerations limited to the esophagus or duodenum. The corresponding UGI involvement in Crohn's colitis was 22%. A cecal patch occurred in 2% of patients.
  
  
  CONCLUSIONS
  Extensive disease and rectal sparing are age-dependent phenotypes in pediatric UC. Rectal sparing, cecal patch, backwash ileitis, and gastric erosions are not uncommon at diagnosis, while gastric ulcerations and erosions in the duodenum or esophagus are. Recognition of atypical phenotypes in pediatric-onset UC is crucial to prevent misclassification of IBD.
authors.affiliation: Pediatric Gastroenterology and Nutrition Unit, E Wolfson Medical Center, Tel Aviv University, Holon, Israel. alevine@wolfson.health.gov.il
authors.forename: Arie
authors.initials: A
authors.lastname: Levine
authors.forename: Charlotte I
authors.initials: CI
authors.lastname: de Bie
authors.forename: Dan
authors.initials: D
authors.lastname: Turner
authors.forename: Salvatore
authors.initials: S
authors.lastname: Cucchiara
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Sladek
authors.forename: M Stephen
authors.initials: MS
authors.lastname: Murphy
authors.forename: Johanna C
authors.initials: JC
authors.lastname: Escher
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D003093:Colitis, Ulcerative / Q000145:classification / Q000473:pathology*; D003106:Colon / Q000473:pathology*; D003424:Crohn Disease / Q000175:diagnosis; D003937:Diagnosis, Differential; D005060:Europe; D005260:Female; D006801:Humans; D007082:Ileum / Q000473:pathology*; D007223:Infant; D007231:Infant, Newborn; D007557:Israel; D016015:Logistic Models; D008297:Male; D010641:Phenotype; D017410:Practice Guidelines as Topic; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012007:Rectum / Q000473:pathology*; D012042:Registries; D041742:Upper Gastrointestinal Tract / Q000473:pathology*