Inflammatory Bowel Disease — Surgical Aspects

Inflammatory bowel disease (IBD) — comprising Crohn's disease (CD) and ulcerative colitis (UC) — is fundamentally a medical disease, but a substantial fraction of patients land on the operating table. For the NEET PG candidate, this topic bridges Medicine and Surgery: you must know who needs surgery, which operation, when not to delay, and the named procedures (strictureplasty, proctocolectomy with ileal pouch–anal anastomosis). UC surgery is potentially curative; CD surgery is palliative/organ-preserving — that single distinction drives almost every decision.

Quick orientation: UC vs CD (the surgically relevant differences)

The pattern of disease decides the operation. Memorise this table cold — it generates the most MCQs.

Feature	Ulcerative Colitis	Crohn's Disease
Site	Rectum → continuous proximal spread, colon only	Mouth to anus; terminal ileum most common
Distribution	Continuous, no skip areas	Skip lesions
Depth	Mucosa + submucosa only	Transmural
Rectal involvement	Almost always (rectum is starting point)	Often spared
Cobblestoning / fistula / stricture	No	Yes (transmural → fistula, stricture, abscess)
Granulomas	Absent	Non-caseating granulomas (40–60%)
Surgery intent	Curative (remove all colon/rectum)	Palliative — disease recurs, conserve bowel
Bowel resection philosophy	Total proctocolectomy	Minimal resection, strictureplasty preferred
p-ANCA / ASCA	p-ANCA positive	ASCA positive
Smoking	Protective (UC is disease of ex-/non-smokers)	Worsens CD
Cancer risk	High (colonic)	Lower than UC but raised (colon + small bowel)

High-yield: UC = mucosal + continuous + curable by colectomy. CD = transmural + skip lesions + NOT cured by surgery (recurs at anastomosis). This dichotomy is the single most tested concept.

Etiology & pathophysiology (surgically relevant points)

IBD results from a dysregulated mucosal immune response to gut flora in a genetically susceptible host. NOD2/CARD15 mutation is associated with ileal/fibrostenotic CD. The transmural inflammation of CD explains its surgical complications: deep fissuring ulcers penetrate the full thickness → fistulae (enterocutaneous, enteroenteric, enterovesical, perianal) and abscesses; chronic transmural fibrosis → strictures and obstruction. UC's superficial mucosal inflammation instead produces friable, easily bleeding mucosa, and when inflammation extends into the muscularis with neural plexus damage → toxic megacolon.

Indications for surgery

Ulcerative colitis

Because the colon and rectum are the only organs involved, removing them cures the disease (and removes future cancer risk).

Emergency / urgent indications

• Toxic megacolon not improving with medical therapy
• Fulminant colitis failing maximal medical management (steroids/ciclosporin/infliximab) within ~3–7 days
• Perforation (free perforation → highest mortality)
• Massive haemorrhage

Elective indications

• Chronic refractory disease / steroid dependence / failed medical therapy
• Dysplasia or carcinoma (high-grade dysplasia or DALM lesion = mandatory colectomy)
• Growth retardation in children
• Intolerable extraintestinal manifestations

Crohn's disease

Surgery is not curative; ~70–80% of CD patients ultimately need an operation, and recurrence at the neo-terminal ileum/anastomosis is the rule. The principle is to operate only for complications and to conserve bowel length (avoid short-bowel syndrome).

• Obstruction from fibrotic stricture (most common indication)
• Fistula (especially enterovesical, enterocutaneous, or high-output internal fistula)
• Abscess (drainage ± resection)
• Perforation / free perforation
• Haemorrhage
• Perianal disease (abscess, complex fistula-in-ano)
• Failure of medical therapy / growth failure
• Dysplasia or malignancy

High-yield: The commonest indication for surgery in Crohn's disease is intestinal obstruction due to stricture. In UC, the commonest elective indication is intractable disease; the most lethal emergency indication is free perforation.

Toxic megacolon — the surgical emergency

A medical emergency where transmural inflammation causes acute, non-obstructive colonic dilatation with systemic toxicity. More classically a complication of UC (also seen in C. difficile colitis, ischaemic colitis, infectious colitis).

Jalan's criteria (diagnosis = radiographic dilatation >6 cm of transverse colon + ≥3 systemic features):

1. Temperature >38 °C (fever)
2. Heart rate >120/min (tachycardia)
3. Neutrophilic leucocytosis >10,500/µL
4. Anaemia

Plus ≥1 of: dehydration, altered sensorium, electrolyte disturbance, hypotension.

High-yield: Transverse colon dilatation >6 cm on plain abdominal X-ray + systemic toxicity = toxic megacolon. Barium enema and colonoscopy are CONTRAINDICATED (risk of perforation).

Management flow: NPO + NG decompression + IV fluids/electrolytes + IV steroids + broad-spectrum antibiotics → stop anticholinergics/opioids/antidiarrhoeals → serial exams and X-rays → no improvement in 24–72 h or perforation → emergency surgery.

The operation of choice in the emergency setting is subtotal/total colectomy with end ileostomy (Hartmann-type, leaving the rectal stump). Definitive restorative surgery (pouch) is done later when the patient is stable. Avoid proctectomy in the acute setting (bleeding, pelvic nerve injury risk in an unstable patient).

Definitive operations in ulcerative colitis

Operation	What is removed/created	Key features
Total proctocolectomy with permanent end ileostomy	Entire colon + rectum + anus	The "gold standard" for cure; needs permanent stoma (Brooke ileostomy). Best for poor sphincters/elderly
Restorative proctocolectomy with IPAA	Entire colon + rectum; anus & sphincters preserved	Procedure of choice in most UC patients wanting continence; ileal pouch (J-pouch) anastomosed to anal canal
Total abdominal colectomy + ileorectal anastomosis	Colon, rectum left in situ	Rarely for UC (rectum remains diseased + cancer risk); more an option in selected Crohn's colitis
Subtotal colectomy + end ileostomy	Colon, rectal stump preserved	The emergency operation; staged

Ileal pouch–anal anastomosis (IPAA) — must-know details

• The J-pouch is the commonest configuration (also S- and W-pouches). A reservoir of distal ileum is created and anastomosed to the anal canal/dentate line.
• Usually done as a staged procedure with a temporary diverting loop ileostomy to protect the anastomosis, closed ~8–12 weeks later.
• Pouchitis is the most common long-term complication of IPAA — inflammation of the pouch presenting with increased frequency, urgency, bleeding; metronidazole/ciprofloxacin is first-line treatment.
• IPAA is contraindicated in Crohn's disease (high failure, fistula, pouch loss) and in poor anal sphincter function / low rectal cancer.

High-yield: Restorative proctocolectomy with ileal pouch–anal anastomosis (IPAA / J-pouch) is the operation of choice for elective UC. Pouchitis is its commonest late complication, treated with metronidazole/ciprofloxacin. IPAA is contraindicated in Crohn's.

Operations in Crohn's disease — conserve bowel

The mantra is "resect as little as possible." Wide margins do NOT reduce recurrence, so only grossly diseased bowel is removed (frozen-section margins are unnecessary).

Strictureplasty — the bowel-sparing star

For short fibrotic strictures (especially in patients with prior resections at risk of short-bowel syndrome), the stricture is widened without resecting bowel.

• Heineke–Mikulicz strictureplasty — for short strictures (<7 cm): longitudinal incision across the stricture, closed transversely (exactly like a pyloroplasty).
• Finney strictureplasty — for medium strictures (7–15 cm): a side-to-side, folded ("U") anastomosis.
• Michelassi (side-to-side isoperistaltic) strictureplasty — for long strictures (>15–20 cm) or multiple closely-spaced strictures.

Contraindications to strictureplasty: free perforation, fistula/abscess at the proposed site, multiple strictures in a very short segment (resect instead), suspicion of malignancy at the stricture, and active bleeding from the site. Hypoalbuminaemia (<2 g/dL) is a relative contraindication.

High-yield: Strictureplasty is preferred over resection in Crohn's to preserve bowel length and prevent short-bowel syndrome. Heineke–Mikulicz for short strictures; Finney for medium; Michelassi (isoperistaltic side-to-side) for long.

Other CD operations

• Limited (ileocaecal/segmental) resection with primary anastomosis for localised disease/obstruction.
• Abscess → percutaneous/operative drainage, often with delayed resection.
• Perianal Crohn's: drain abscesses; non-cutting seton for complex/high fistulae (cutting seton risks incontinence given sphincter involvement). Optimise medical therapy (infliximab/metronidazole) before definitive fistula surgery; consider proctectomy/diversion for refractory severe perianal disease.

Diagnosis & investigation of choice

• Colonoscopy with ileoscopy + multiple biopsies = the investigation of choice for diagnosis and to map disease; reveals continuous friable mucosa (UC) vs skip lesions, cobblestoning, aphthous/deep ulcers (CD).
• Histology: UC — crypt abscesses, mucosal/submucosal limited inflammation, depleted goblet cells. CD — transmural inflammation + non-caseating granulomas + lymphoid aggregates.
• CT enterography / MR enterography — best for small-bowel CD, strictures, fistulae, abscesses. MRI pelvis is investigation of choice for perianal fistula mapping.
• Plain abdominal X-ray — for toxic megacolon/perforation (free air, dilatation).
• Serology (adjunct): p-ANCA → UC; ASCA → CD.
• Faecal calprotectin for activity monitoring.

High-yield: MRI pelvis is the imaging of choice for perianal Crohn's fistula; CT/MR enterography for small-bowel Crohn's. Colonoscopy + biopsy confirms the diagnosis. In suspected toxic megacolon, avoid colonoscopy/barium enema.

Cancer surveillance & risk

• Cancer risk in UC rises with duration (>8–10 years), pancolitis, and primary sclerosing cholangitis (PSC).
• Colonoscopic surveillance with biopsies begins ~8 years after pancolitis onset (immediately at diagnosis if coexisting PSC).
• High-grade dysplasia or a dysplasia-associated lesion/mass (DALM) → proctocolectomy.
• CD carries raised colorectal cancer risk and additionally small-bowel adenocarcinoma (notably in long-standing strictured segments and bypassed loops).

Extraintestinal manifestations (EIMs)

Split EIMs by whether they track colitis activity — a favourite MCQ.

Parallel bowel activity (improve after colectomy)	Independent of bowel activity
Peripheral arthritis (large joints)	Ankylosing spondylitis / sacroiliitis (HLA-B27)
Erythema nodosum	Pyoderma gangrenosum (often independent)
Episcleritis	Uveitis
Oral aphthous ulcers	Primary sclerosing cholangitis (PSC) — UC > CD

• PSC does not improve after colectomy and carries cholangiocarcinoma risk; classically associated with UC.
• Gallstones and renal oxalate stones are linked to terminal ileal Crohn's (bile-salt malabsorption → cholesterol stones; fat malabsorption → enteric hyperoxaluria → oxalate stones).

High-yield: Pyoderma gangrenosum, ankylosing spondylitis/sacroiliitis, uveitis, and PSC run an independent course and do NOT remit with colectomy. Peripheral arthritis, erythema nodosum, episcleritis parallel disease activity.

Complications (surgical and disease-related)

• CD: stricture/obstruction, fistula (entero-enteric, enterovesical → pneumaturia/faecaluria, enterocutaneous), abscess, perianal disease, short-bowel syndrome (after repeated resections), gallstones/oxalate stones, malabsorption (B12 deficiency from terminal ileal disease).
• UC: toxic megacolon, perforation, massive haemorrhage, colorectal carcinoma, pouchitis (post-IPAA).
• Postoperative recurrence in CD: endoscopic recurrence at the neo-terminal ileum is near-universal; smoking cessation and prophylactic medical therapy reduce it.

Drug of choice / medical bridge (so you can identify "failed medical therapy")

• Acute severe UC: IV corticosteroids → rescue with ciclosporin or infliximab → colectomy if no response by day 3–7.
• Maintenance UC: 5-ASA (mesalazine/sulfasalazine).
• CD: induction with steroids/biologics; maintenance with thiopurines (azathioprine), methotrexate, anti-TNF (infliximab, adalimumab). Perianal fistulising CD → infliximab ± antibiotics (metronidazole).
• Pouchitis → metronidazole/ciprofloxacin.

Key differentials

• Intestinal tuberculosis — the great mimic of ileocaecal CD in India: caseating granulomas, transverse ulcers, less common skip lesions, AFB/PCR positive, ASCA negative → a therapeutic trial of ATT may be needed.
• Infective/ischaemic colitis, C. difficile colitis (also causes toxic megacolon).
• Behçet disease, intestinal lymphoma, NSAID enteropathy.
• Appendicitis vs acute ileocaecal Crohn's.

High-yield: In Indian PG exams, ileocaecal TB vs Crohn's is the classic differential — caseating granulomas + transverse ulcers + AFB favour TB; non-caseating granulomas + longitudinal/aphthous ulcers + skip lesions + ASCA favour Crohn's.

Recently asked / exam angle

• "Commonest indication for surgery in Crohn's disease?" → Obstruction (stricture).
• "Operation of choice in ulcerative colitis (elective)?" → Restorative proctocolectomy with IPAA (J-pouch).
• "Strictureplasty for short stricture in Crohn's?" → Heineke–Mikulicz (Finney for medium, Michelassi for long).
• "Toxic megacolon diameter cut-off?" → >6 cm transverse colon; colonoscopy/barium contraindicated.
• "Which EIM does NOT improve after colectomy?" → PSC / ankylosing spondylitis / pyoderma gangrenosum / uveitis.
• "Commonest complication after IPAA?" → Pouchitis → metronidazole.
• "Which IBD is curable by surgery?" → Ulcerative colitis.
• "Emergency surgery of choice in fulminant UC / toxic megacolon?" → Subtotal colectomy with end ileostomy (preserve rectal stump).
• Image-based: skip lesions / string sign of Kantor (CD) on barium; lead-pipe colon with loss of haustrations (UC).

Mnemonic for Crohn's transmural features — "Crohn's = COBBLESTONE": Creeping fat, Obstruction (commonest surgical indication), Bowel skip lesions, Bowel-wall thickening, Linear/longitudinal ulcers, Entero-fistulae, Strictures, Transmural, Oral-to-anus, Non-caseating granulomas, Extraintestinal.

Rapid revision

1. UC = mucosal, continuous, rectum-onwards, curable by total proctocolectomy.
2. CD = transmural, skip lesions, mouth-to-anus, NOT curable — conserve bowel.
3. Commonest CD surgical indication = stricture/obstruction.
4. Toxic megacolon = transverse colon >6 cm + toxicity; avoid scope/barium.
5. Emergency colitis surgery = subtotal colectomy + end ileostomy, rectal stump left.
6. Elective UC operation of choice = restorative proctocolectomy with IPAA (J-pouch); pouchitis = commonest late complication → metronidazole/ciprofloxacin.
7. IPAA is contraindicated in Crohn's.
8. Strictureplasty: Heineke–Mikulicz (short), Finney (medium), Michelassi (long) — saves bowel, prevents short-bowel syndrome.
9. Perianal complex CD fistula → non-cutting seton + infliximab; map with MRI pelvis.
10. PSC, ankylosing spondylitis, uveitis, pyoderma gangrenosum = EIMs independent of colitis activity (don't remit after colectomy).
11. High-grade dysplasia/DALM in UC → proctocolectomy; surveillance from 8 years (immediate if PSC).
12. Crohn's terminal ileal disease → B12 deficiency, gallstones, oxalate renal stones; classic India differential = ileocaecal TB.