Staging
Paris classification
The 2011 Paris classification modifies the Montreal system to describe pediatric inflammatory bowel disease phenotype.
Stages
- CD-A
Crohn disease age
A1a: diagnosis before age 10; A1b: age 10 to under 17; A2: age 17–40; A3: over 40.
- CD-L
Crohn disease location
L1: ileal; L2: colonic; L3: ileocolonic; L4a: proximal to Treitz ligament; L4b: distal to Treitz ligament, above distal ileum; L4 modifies L1–L3.
- CD-B
Crohn disease behavior
B1: non-stricturing, non-penetrating; B2: stricturing; B3: penetrating; B2B3: both; P records perianal disease.
- Pediatric modifiers
Growth and colitis modifiers
G0/G1 records absence or presence of growth failure; UC E4 extends proximal to the hepatic flexure; S0/S1 records severe disease never/ever.
Judged onAge at diagnosis, disease location and behavior, growth failure, and ulcerative colitis extent or severe activity.
The Paris classification adapts the Montreal phenotype system for children and adolescents with inflammatory bowel disease. It separates the youngest pediatric age group and refines how upper gastrointestinal Crohn disease and combined stricturing and penetrating behavior are recorded. Pediatric modifiers also capture growth failure and selected ulcerative colitis features. Clinicians use it to record a child’s disease pattern.