Ulcerative Colitis vs Crohn’s Disease

( Comparative Study )

Feature	Ulcerative Colitis	Crohn’s Disease
Area involved	Colon only	Anywhere mouth → anus
Most common site	Rectum always involved	Terminal ileum common
Pattern	Continuous	Skip lesions
Depth	Mucosa & submucosa	Transmural
Rectum	Always involved	Often spared
Fistula	Rare	Common
Stricture	Rare	Common
Granuloma	Absent	Present (non-caseating)
Bloody diarrhea	Common	Less common
Surgery	Curative	Not curative

Easy Memory Tricks

• UC = U Continues → Continuous lesion from rectum limited to colon.

• Crohn = Cracks & Cobblestones → Deep fissures and cobblestone appearance.

• UC = Surface disease (mucosal only).

• Crohn = Whole wall disease (transmural).

• UC surgery cures disease; Crohn disease recurs.

Pathology

• UC: Rectum involved, continuous spread, pseudopolyps, toxic megacolon risk.

• Crohn: Skip lesions, creeping fat, deep fissures, thick bowel wall, granulomas.

Clinical Features

• UC: Bloody diarrhea, mild pain, less fever, toxic megacolon.

• Crohn: Weight loss, severe pain, fistula, abscess, obstruction.

Investigations

• UC: Colonoscopy shows continuous inflammation and pseudopolyps.

• Crohn: Cobblestoning, deep ulcers, string sign in terminal ileum.

Complications

• UC: Toxic megacolon, hemorrhage, perforation, colorectal carcinoma.

• Crohn: Fistula, abscess, obstruction, malabsorption.

Medical Management

• Steroids

• 5-ASA (Mesalamine)

• Immunosuppressants

• Biologics

Surgical Management

• UC: Total proctocolectomy + ileostomy or IPAA. Surgery is curative.

• Crohn: Limited resection, strictureplasty, abscess drainage. Surgery is not curative.

Viva Questions

• Why fistula common in Crohn? → Transmural inflammation.

• Why toxic megacolon in UC? → Severe inflammation causing colonic paralysis.

• Which has higher cancer risk? → Long-standing UC.

Rapid Revision

• UC: Colon only, continuous, rectum involved, bloody diarrhea, surgery cures.

• Crohn: Anywhere in GIT, skip lesions, transmural, fistula/stricture, recurrence common.

High-Yield Mnemonics

• CROHN = Cobblestone, Recurrence, Obstruction, Holes (fistula), Non-caseating granuloma

• ULCER = Uniform lesion, Limited to colon, Cancer risk, Extraintestinal features, Rectum involved