A decade of inflammatory bowel disease: a single center experience in Egypt

The Egyptian Journal of Internal Medicine

Table 3 Vienna and Montreal classification for Crohn’s disease [10]

	Vienna	Montreal
Age at diagnosis	A1 below 40 years	A1 below 16 years
	A2 above 40 years	A2 between 17 and 40 years
	A2 above 40 years	A3 above 40 years
Location	L1 ileal	L1 ileal
	L2 colonic	L2 colonic
	L3 ileocolonic	L3 ileocolonic
	L4 upper	L4 isolated upper disease^a
Behavior	B1 non-stricturing, non-penetrating	B1 non-stricturing, non-penetrating
	B2 stricturing	B2 stricturing
	B3 penetrating	B3 penetrating
	B3 penetrating	p perianal disease modifier^△

^△“p” is added to B1–B3 when concomitant perianal disease is present
^aL4 is a modifier that can be added to L1–L3 when concomitant upper gastrointestinal disease is present