Crohn Disease and Its Surgical Management

Introduction

• Crohn disease is an incurable, chronic inflammatory bowel disease (IBD) of unknown etiology.
• Characterized by transmural inflammation that can involve any part of the gastrointestinal tract, from mouth to anus.
• Presentations vary widely; a multidisciplinary team approach is essential for optimal care.

Epidemiology

• Incidence in North America: 3.1 to 20.2 cases per 100,000 person-years.
• Prevalence is increasing, possibly due to improved survival from advanced therapies.
• Estimated prevalence: 201 cases per 100,000 people in a large cohort study.

Risk Factors

General Factors

• Gender: Slight female predominance; no hormonal effect on disease expression.
• Age: Bimodal distribution with peaks in the second/third and sixth/seventh decades.
• Ethnicity: Higher incidence in Jewish and white populations.

Environmental Factors

• Microbial Imbalance: Altered gut microbiota may contribute to disease.
• Medications: Antibiotics, NSAIDs, and oral contraceptives may impact development.
• Diet: Western diet (processed, fried, low-fiber, sugary foods) implicated.
• Hygiene Hypothesis: Improved hygiene associated with increased risk.
• Smoking:
  • Increases risk of developing Crohn disease.
  • Associated with higher disease recurrence and severity.

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Genetic Factors in Crohn Disease

Familial Risk

• 15% of patients with Crohn disease have a family history of Inflammatory Bowel Disease (IBD).
• Patients with a first-degree relative with IBD are 3 to 20 times more likely to develop the disease than the general population.
• Inheritance follows a non-Mendelian pattern, indicating environmental factors also play a significant role.

Twin Studies

• Monozygotic twins have a 44% concordance rate for Crohn disease.
• Dizygotic twins show a much lower 3.8% concordance rate.
• This suggests that genetic predisposition is incomplete, and environmental triggers are essential for disease manifestation.

Concordance in Familial Disease

• Concordance exists in disease location (e.g., colonic vs. ileal involvement) and phenotype (e.g., fistulizing vs. fibrostenotic forms).
• Genetic anticipation has been observed, where the disease tends to appear earlier and in a more severe form in successive generations.

Animal Models

• Gene alterations affecting the adaptive and innate immune systems and epithelial function have been linked to Crohn disease.
• Single gene alterations result in variable clinical presentations depending on the genetic background (e.g., mouse strain).
• Germ-free environments are protective against IBD development in animal models, indicating a role for microbial interactions in disease pathogenesis.

Genome-Wide Association Studies (GWAS)

• More than 100 susceptibility loci have been identified for IBD, offering insights into the genetic mechanisms underlying Crohn disease.

Key Genes and Pathways

• NOD2/CARD15: IBD 1 Gene
  • Associated with ileal Crohn disease.
  • Mutations disrupt innate immune pathways, impairing the recognition of microbial products in the cytoplasm.
• Autophagy Pathway Genes:
  • ATG16L1, IRGM, and LRRK: Regulate the autophagy process, crucial for removing intracellular microorganisms and recycling cell components.
• Adaptive Immune Function Genes:
  • IL23R, IL12B, STAT3, JAK2, TYK2, IL27, TNFSF15: Involved in immune regulation and inflammatory responses.
• Epithelial Cell Function Genes:
  • XBP1, NOD2: Critical for maintaining intestinal barrier function and cellular stress responses.

Clinical Relevance of Genetic Testing

• No standard genetic testing for Crohn disease is currently available.
• Although certain gene mutations are associated with Crohn disease, their presence alone is not sufficient for diagnosis.
• Environmental factors remain a significant component in the development and progression of the disease, even in genetically susceptible individuals.

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Natural History and Pathophysiology

• Involves environmental and genetic factors altering mucosal integrity.
• Complex changes in local and systemic immune responses.
• Disease Phases:
  • Active Disease.
  • Remission.
• Disease Progression:
  • Only 10–20% achieve prolonged remission after initial presentation.
  • 53% develop strictures or penetrating disease within 10 years.
• Risk Factors for Severe Disease:
  • Age <40 at presentation.
  • Perianal or rectal lesions.
  • Smoking.
  • Low education level.
  • Initial steroid use.

• Fistulas:

  • Common complication.
  • High recurrence rates (59–82%).

  

Surgical Intervention

• 80% will require surgery during disease course.
• Indications:
  • Failure of medical therapy.
  • Complications: Abscess, fistula, stricture.
• Surgery rates increase over time:
  • Less than 2% in the first year.
  • Up to 28% by 10 years post-diagnosis.
• Improved therapies and specialized care may reduce surgical needs.

Long-Term Outcomes

• 20-year survival: 93–94%.
• Quality of Life:
  • Lower than healthy individuals and those with ulcerative colitis.
  • Improves with disease remission, regardless of treatment method.
• Financial Burden:
  • High direct costs (treatment, hospitalization).
  • Indirect costs (missed work, caretaking).

Clinical Presentation

• Symptoms vary widely due to heterogeneous disease nature.
• Abdominal Pain:
  • Mild and diffuse (inflammation).
  • Colicky (obstruction).
• Diarrhea:
  • From impaired absorption, bile salt malabsorption, or steatorrhea.
• Fistulas:
  • Develop in one-third of patients within 10 years.
  • Common types:
    • Enterovesical. = Most Common
    • Enterocutaneous.
    • Enteroenteric.
    • Enterovaginal.
• Bleeding:
  • Severe acute hemorrhage is rare (<10%).
  • Occult bleeding in up to 24%.
• Perianal Disease:
  • Initial symptom in 10%.
  • Sole disease location in ~5%.
  • 30% experience perianal involvement during disease course.
• Systemic Symptoms:
  • Weight loss.
  • Fatigue and malaise.
  • Fever (note: high fevers may indicate infection).

Extraintestinal Manifestations

• Occur in 6–40% of patients.
• Common Manifestations:
  • Arthritis: 20%.
  • Eye Involvement: Iritis/Uveitis (5%).
  • Skin Disorders: Pyoderma gangrenosum, erythema nodosum (10%).
  • Primary Sclerosing Cholangitis: 5%.
  • Secondary Amyloidosis: Rare.
  • Thromboembolic Disease: Due to hypercoagulability.

Disease Classification

• Vienna Classification System:
  • Age at Diagnosis:
    • A1: <40 years.
    • A2: ≥40 years.
  • Disease Location:
    • L1: Terminal ileum.
    • L2: Colon.
    • L3: Ileocolon.
    • L4: Upper GI tract.
  • Disease Behavior:
    • B1: Inflammatory.
    • B2: Stricturing.
    • B3: Penetrating.
• Helps tailor therapies and predict prognosis.

Testing

Laboratory Studies

• Inflammatory Markers:
  • Elevated WBC, platelet count.
  • Increased ESR and C-reactive protein.
• Anemia Assessment:
  • Complete blood count.
  • Serum iron and vitamin B12 levels.
• Serologic Tests:
  • Anti-Saccharomyces cerevisiae antibodies (ASCA).
  • Perinuclear antineutrophil cytoplasmic antibodies (pANCA).
  • Anti-OmpC antibody.
• Stool Markers:
  • Fecal calprotectin.
  • Lactoferrin.

Endoscopy

• Ileocolonoscopy:
  • Evaluates colon and terminal ileum.
  • Findings suggestive of Crohn disease:
    • Aphthous ulcers.
    • Cobblestoning.
    • Skip lesions.
    • Rectal sparing.
• Esophagogastroduodenoscopy:
  • For upper GI symptoms.
• Scoring Systems:
  • Crohn's Disease Endoscopic Index of Severity (CDEIS).
  • Simplified Endoscopic Activity Score for Crohn's Disease (SES-CD).
    • Simplified Endoscopic Activity Score for Crohn’s Disease (SES-CD) is a simpler scoring system, which rates the (1) presence and size of ulcers, (2) extent of ulcerated surface, (3) extent of affected surface, 4) presence and type of narrowing.
  • Rutgeerts Score: Predicts postoperative recurrence.

Wireless Video Capsule Endoscopy

• Evaluates small bowel involvement.
• Contraindicated in suspected strictures (risk of capsule retention).
• Patency capsules may be used prior to test.

Radiographic Studies

• Essential for assessing small intestine and extraintestinal complications.
• Radiation Exposure:
  • Minimize ionizing radiation, especially in young patients.

Ultrasound

• Transabdominal Ultrasound:
  • Advantages: Non-invasive, no radiation.
  • Limitations: Operator-dependent, less effective with obesity or gas.

Barium Studies

• Enteroclysis and Small Bowel Follow-Through:

  • Detect strictures, fistulas, mucosal patterns.
  • Enteroclysis offers uniform contrast but is less comfortable.

  

Computed Tomography (CT)

• Traditional CT:
  • Identifies transmural and extraintestinal disease.
  • Limitations in detecting subtle mucosal lesions.

• CT Enterography:

  • Uses neutral contrast for better small bowel visualization.
  • Detects inflammation, strictures, fistulas, abscesses.

  

Magnetic Resonance Imaging (MRI)

• Traditional MRI:
  • Similar to CT but without radiation.
• MR Enterography:
  • Preferred modality for small bowel assessment.
  • Distinguishes active inflammation from chronic fibrosis.
  • Advantages: No ionizing radiation, detailed imaging.

Conclusion

• Crohn disease is a complex, chronic condition requiring personalized care.
• Understanding risk factors, clinical presentations, and diagnostic tools is crucial.
• Advancements in therapy and multidisciplinary approaches have improved management.
• Tailored treatments based on individual disease profiles enhance patient outcomes.

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Pathology

• Full-thickness inflammatory lesions can arise from any part of the gastrointestinal tract, from the mouth to the anus.
• Most common site: Ileocecal area.
  • 80% of patients have small bowel involvement.
  • One-third have disease confined to the small intestine.
  • 20% have disease confined to the colon.
  • One-third have perianal disease.
• Upper GI tract involvement:
  • Historically thought to be rare.
  • Increased use of upper endoscopy and biopsy reveals high prevalence.
  • Up to 50% have active disease on biopsy despite lack of symptoms.
  • Common sites: Gastric antrum, duodenum.
  • Rarely affected: Esophagus, other regions of the stomach.

Gross Features

• Two distinct phases observed pathologically:
  • Active Phase:
    • Presence of inflammatory changes.
    • Active lesions:
      • Start as small, flat, soft aphthous ulcers with pale, white centers and surrounding erythema.
      • Deepen into transmural inflammatory lesions, leading to abscesses and fistulae.
      • Healing and scarring can lead to strictures and obstructive lesions.
    • Skip lesions:
      • Lesions can be scattered with normal mucosa in between.
      • Leads to cobblestone appearance.
      • Lesions can coalesce into continuous patterns similar to ulcerative colitis.
    • Other features:
      • Bowel wall and mesenteric thickening, possibly narrowing the lumen.
      • Creeping fat:
        • Mesenteric fat extends onto the serosal surface of the intestine.
        • Best observed during surgical exploration.
      • Mesenteric thickening from fat deposition and enlarged lymph nodes.

  • Remission Phase:

    • Healing and fibrosis of previously inflamed tissue.
    • Fibrosis can lead to stenosis of the intestinal lumen.

    

    

Microscopic Features

• Microabscesses:
  • Inflammatory cell aggregates form under aphthous ulcerations.
  • Associated with intestinal crypts, can lead to fissure formation.

• Noncaseating granulomas:

  • Presence of multinucleated giant cells.
  • Considered pathognomonic for Crohn disease.
  • However, only about 50% of patients display granulomas on histology.

  

  

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Treatment

Goals

• Reduce symptoms.
• Improve quality of life.
• Minimize side effects of treatments.
• Induce remission of active disease.
• Maintain remission long-term.

Medical Therapy

• Tailored based on:
  • Severity of inflammation: mild, moderate, severe.
  • Location of active lesions.
  • Previous responsiveness to therapies.

• Grading Systems:

  • Crohn's Disease Activity Index (CDAI).

  

  • Harvey-Bradshaw Index.
    • Assess factors like stool pattern, abdominal pain, well-being, complications, anemia, weight change.
  • Disease Grades:
  • Asymptomatic remission.
  • Mild to moderate disease.
  • Moderate to severe disease.
  • Severe-fulminant disease.
  • Treatment Strategies:
  • Step-up approach:
    • Start with least potent therapies.
    • Escalate to more potent if ineffective.
  • Top-down approach:
    • Start with more potent therapies (biologics, immunomodulators).
    • Aim to avoid glucocorticoid dependence.

Medications

• Conventional Glucocorticoids:
  • Prednisone.
  • Used to induce remission.
  • Limitations:
    • Side effects.
    • Steroid dependence.
    • Steroid resistance.
• Nonsystemic Glucocorticoids:
  • Budesonide.
  • Less systemic effects due to first-pass liver metabolism.
  • Effective in up to 70% of patients.
  • Less effective in left-sided colonic disease.
• Oral 5-Aminosalicylates:
  • Mesalamine, Sulfasalazine.
  • Mixed results in efficacy.
  • Not very effective in maintaining remission.
• Antibiotics:
  • Metronidazole, Ciprofloxacin.
  • Used to induce remission in mild to moderate disease.
  • Concerns:
    • Antibiotic resistance.
    • Used as second-line therapy.
• Immunomodulators:
  • Azathioprine, 6-Mercaptopurine (6-MP), Methotrexate.
  • Azathioprine/6-MP:
    • Reduce active lymphocytes.
    • Purine antimetabolites blocking lymphocyte proliferation.
    • Onset: 3 to 6 months.
    • Side effects: Bone marrow suppression, infection risk, allergic reactions, pancreatitis.
  • Methotrexate:
    • Inhibits dihydrofolate reductase.
    • Blocks DNA synthesis.
    • Onset: 1 to 3 months.
    • Side effects: Liver toxicity, nausea, teratogenic.
• Biologic Therapies:
  • Anti-TNF-α agents: Infliximab, Adalimumab, Certolizumab pegol.
  • Mechanism: Neutralize TNF-α, reducing inflammation.
  • Efficacy:
    • More likely to achieve remission compared to placebo.
    • Number needed to treat:
      • 8 to achieve one remission.
      • 4 to prevent one relapse.
  • Other Biologics:
    • Natalizumab: Anti-α4 integrin; limited by side effects.
    • Ustekinumab: Blocks IL-12 and IL-23.
    • Vedolizumab: Anti-α4-β7 integrin; approved for moderate to severe disease.

Maintaining Remission

• Medications:
  • Azathioprine and 6-MP:
    • Proven efficacy in maintaining remission.
    • Mixed results upon withdrawal.
  • Methotrexate:
    • Used after induction of remission.
    • Requires assessment for liver disease risk.
  • Biologic Agents:
    • Increasingly used for maintenance.
    • Concerns:
      • Development of antibodies.
      • Hypersensitivity reactions.
      • Resistance over time.
• Not Recommended:
  • Steroids:
    • Long-term side effects.
    • Budesonide not effective beyond 6 months.
  • 5-Aminosalicylates:
    • Limited efficacy in maintaining remission.
• Considerations:
  • Balance efficacy, adverse effects, and cost.
  • Biologics are more expensive than immunomodulators.
  • Trials off medication may be considered with careful monitoring.

Nutrition

Importance

• Maximize nutritional status.
• Maintain adequate intake.
• Avoid foods that may precipitate flares.

Nutritional Assessment

• Focused history and physical exam.
• Measure:
  • Dietary intake.
  • Energy expenditure.
  • Body composition.
  • Serum studies: Albumin, prealbumin, iron studies.

Malnutrition

• Common in Crohn disease patients.
• Causes:
  • Reduced intake due to anorexia, pain, obstructions.
  • Malabsorption.
  • Drug effects.
  • Increased metabolic requirements:
    • Vitamin B12, calcium, fat-soluble vitamins, folate, iron, selenium, zinc.
• Consequences:
  • Growth failure and pubertal delay in children.
  • Bone loss.
  • Delayed healing of fistulas and wounds.
  • Increased susceptibility to infection.

Nutritional Support

• Routes:
  • Oral (preferred).
  • Enteral feeding.
  • Parenteral nutrition.
• Parenteral Nutrition:
  • Reserved for patients unable to tolerate enteral feeding.
  • Risks:
    • Complications from intravenous access.
    • Expensive.
  • Indications:
    • Bowel obstruction.
    • High-output fistulas.
    • Short-gut syndrome.
• Monitoring:
  • Watch for refeeding syndrome in severely malnourished patients.
  • Close monitoring of electrolytes, especially phosphate levels.

Nutrition as Primary Therapy

• Dietary Adjustments:
  • Elimination diets to identify trigger foods.
  • Restrictive diets to reduce certain carbohydrates and processed foods.
  • Results of studies are mixed.
• Enteral Nutrition:
  • Elemental vs. nonelemental formulas show no difference in efficacy.
  • Not as effective as steroids in inducing remission.
  • More effective than placebo.
• Supplementation:
  • No convincing evidence supporting:
    • High-fiber diets.
    • Probiotics.
    • Omega-3 fatty acids.
    • Glutamine.
    • Antioxidants.

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Crohn Disease and Its Surgical Management

Surgical Therapy

Introduction

• Surgical therapy is focused on managing complications of small bowel Crohn disease.
• Surgery does not cure Crohn disease but addresses complications not amenable to medical or endoscopic therapy.
• Important factors in surgical decision-making:
  • Chronic nature of the disease with high recurrence rates.
  • Presence of adhesions, malnutrition, and immunosuppressive therapy.

Indications for Surgery

• Obstruction due to fibrotic stricture.
• Perforation:
  • Free perforation (surgical emergency).
  • Contained perforation not resolved by interventional radiology.
• Fistulas resistant to medical therapy.
• Failure of medical therapy:
  • Maximal therapy cannot control active disease symptoms.
  • Failure to maintain remission after induction.
  • Significant medication-associated complications.
• Other indications:
  • Massive gastrointestinal hemorrhage.
  • Cancer.
  • Toxic megacolon.
  • Growth retardation.

Preoperative Preparation

• Conduct a thorough history and physical examination.
• Assess for comorbid conditions.
• Evaluate nutritional status:
  • Malnutrition increases postoperative complication risk.
  • Optimize nutrition via oral or enteral supplementation; consider total parenteral nutrition if necessary.
• Smoking cessation to reduce recurrence risk.
• Complete gastrointestinal evaluation:
  • Endoscopy and cross-sectional imaging (MR or CT enterography).
  • Identify all areas of disease to aid surgical planning.
• Medication management:
  • Discontinue immunosuppressive drugs safely before surgery, except corticosteroids.
  • Provide stress-dose steroids for patients on long-term corticosteroids.
• Consent and patient education:
  • Discuss possibility of needing an intestinal stoma.
  • Preoperative meeting with an enterostomal therapist for site marking and stoma care education.

Operative Strategies and Techniques

Abdominal Incision

• Laparoscopic approach is suitable for many patients.
• Choose incisions mindful of potential future surgeries:
  • Midline laparotomy or low transverse Pfannenstiel incisions are preferred.
  • Low Pfannenstiel incision offers good access and better cosmetic outcomes with lower hernia rates.

Abdominal Exploration and Identification of Diseased Segments

• Assess the entire abdominal cavity:
  • Identify stenosis, perforations, abscesses, masses, and fistulas.
• Diseased segments may show:
  • Bowel wall thickening.
  • Mesenteric thickening.
  • Serosal hyperemia.
  • Creeping fat (mesenteric fat extending onto bowel surface).
• Use visual inspection and palpation to identify subtle lesions.

Management of Stenotic Bowel Segments

• Goal: Relieve obstruction while preserving bowel length.
• Surgical options:
  • Resection of diseased segments.
  • Stricturoplasty to widen the narrowed lumen without resection.
• Stricturoplasty is preferred to avoid short bowel syndrome unless contraindicated.

Stricturoplasty Techniques

1. For Short Segment Strictures:

   • Heineke-Mikulicz Stricturoplasty:

     • For short strictures (<10 cm).
     • Longitudinal incision across stricture, closed transversely.

     

   • Judd Stricturoplasty:

     • Resection of a small bowel wall portion, transverse closure.
     • Useful for small areas with penetration or wall damage.

     

   • Moskel-Walske-Neumayer Stricturoplasty:

     • Y-shaped enterotomy with transverse closure.
     • Reduces tension in cases with prestenotic dilation.

     

2. For Long Segment Strictures:

   • Finney Stricturoplasty:

     • For strictures 10–15 cm long.
     • Creates a U-shaped bend and side-to-side closure.

     

   • Michelassi Stricturoplasty:

     • For long strictures.
     • Side-to-side isoperistaltic strictureplasty preserving bowel length.

   

   • Jaboulay:

     • Jaboulay stricturoplasty: Two separate antimesenteric longitudinal enterotomies are performed, leaving the most strictured portion of the bowel unopened. The bowel is then oriented in a side-to-side fashion by creating a U-shaped bend similar to the Finney technique. The bowel is then closed creating a side-to-side enteroenterostomy using either a sutured or stapling technique.

       

Bowel Resection and Anastomotic Techniques

• Resection:
  • Identify proximal and distal disease extent.
  • Narrow margins beyond gross disease are adequate.
• Anastomosis considerations:
  • Ensure adequate blood supply and tension-free connection.
  • Consider diameter mismatch between bowel segments.
  • Be cautious of distal obstruction affecting anastomosis.
• Anastomosis methods:
  • Stapled vs. handsewn based on surgeon preference.
  • Functional end-to-end stapled anastomosis may be superior, especially with varying bowel calibers.

Stoma Formation

• Preoperative planning is essential.
• Stoma site selection:
  • Within the rectus muscle to reduce hernia risk.
  • Away from scars, bony prominences, and skin folds.
• Technique:
  • Create an appropriate opening through the abdominal wall layers.
  • Mature the stoma with absorbable sutures in a Brooke fashion.
  • Ensure at least 2–3 cm of everted bowel to protect skin.

Bypass Procedures

• Rarely used for jejunum or ileum.
• Duodenal disease may require:
  • Gastrojejunostomy.
  • Duodenojejunostomy.

Minimally Invasive Surgery in Crohn Disease

• Challenges:
  • Inflammation causing friable tissues.
  • Thickened mesentery complicating bowel mobilization.
  • Previous surgeries leading to adhesions.
• Benefits:
  • Reduced postoperative complications.
  • Shorter hospital stay.
  • Improved cosmetic outcomes.
• Contraindications:
  • Uncorrected coagulopathy.
  • Intraabdominal varices from portal hypertension.
  • Dense adhesions or multiple prior open surgeries.
  • Diffuse peritonitis.
  • Severe obstruction with massively dilated intestines.

Conclusion

• Surgical management of small bowel Crohn disease focuses on treating complications while preserving bowel length.
• Careful preoperative preparation and patient counseling are essential.
• A variety of surgical techniques are available, and the choice depends on disease presentation and severity.
• Minimally invasive approaches are beneficial but require careful patient selection.

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Treatment of Small Bowel Crohn Disease Complications

Vienna Classification System

• Vienna Classification groups Crohn disease patients based on:
  • Disease Behavior:
    • Inflammatory
    • Stricturing
    • Penetrating
  • Age at Diagnosis:
    • <40 years
    • ≥40 years
  • Disease Location:
    • Terminal ileum
    • Colon
    • Ileocolonic
    • Upper gastrointestinal
• Surgical therapy is most dependent on disease behavior, particularly stricturing and penetrating types.

Stricturing Disease

• Leads to symptoms ranging from chronic low-grade obstructions to acute high-grade or complete obstructions.
• Clinical Presentation:
  • Chronic Symptoms:
    • Intermittent intolerance to solids and liquids
    • Abdominal pain
    • Weight loss
    • Malnutrition
  • Acute Symptoms:
    • Severe abdominal pain
    • Nausea and vomiting
    • Abdominal distention
    • Possible obstipation
• Initial Management:
  • Bowel rest
  • Nasogastric decompression
  • Resuscitation
• Diagnostic Evaluation:
  • Endoscopy or contrast imaging to assess for inflammation.
• Medical Therapy:
  • Aggressive medical treatment if inflammation contributes to stenosis.
• Dietary Management:
  • Low-residue diet for intermittent symptoms to reduce partial obstructions.
• Surgical Intervention:
  • Indicated for:
    • Complete bowel obstruction
    • Failure of medical management
  • Surgical Options:
    • Bowel resection
    • Stricturoplasty
  • Considerations:
    • Health of surrounding bowel
    • Remaining bowel length
    • Nutritional status
    • Recent steroid or biologic therapy
    • Presence of other lesions (phlegmon, abscess, fistula)

Penetrating Disease: Enteric Fistulas and Perforation

• Penetrating disease leads to fistulas and perforations.

• Types of Fistulas:

  • Enteroenteric: Intestine to intestine

  

  • Enterocolonic: Small intestine to colon
  • Enterovesical: Intestine to bladder
  • Enteroureteral: Intestine to ureter
  • Enterovaginal: Intestine to vagina
  • Enterocutaneous: Intestine to skin
  • Prevalence:
  • Fistulas develop in 35% of patients.
  • Two-thirds are perianal fistulas.
  • Complications:
  • Diarrhea and malabsorption due to bacterial overgrowth or bypassing bowel segments.
  • Infection from communication with genitourinary systems.
  • Quality of life reduction due to external drainage.
  • Medical Management:
  • Immunomodulators: Azathioprine, 6-mercaptopurine
  • Biologic Agents: Infliximab
  • Effectiveness:
    • Significant improvement in fistula healing.
    • Data mainly from perianal fistulas.

Specific Fistulas:

Enteroenteric Fistulas

• Often asymptomatic; may be incidental findings.
• Management:
  • Resect diseased segments.
  • Primary repair of uninvolved bowel.

Ileosigmoid Fistulas

• Occur in up to 6% of patients.
• Symptoms: Abdominal pain, diarrhea, malabsorption.
• Management:
  • Separate small bowel from sigmoid colon.
  • Resect diseased ileum.
  • Primary closure of colon if uninvolved.
  • Resect sigmoid colon if affected; consider primary anastomosis.

Enterovesical and Enteroureteral Fistulas

• Occur in 1–8% of patients.
• Symptoms:
  • Dysuria, urinary urgency and frequency
  • Suprapubic discomfort
  • Pneumaturia (air in urine)
  • Fecaluria (feces in urine)
• Diagnosis:
  • Cystoscopy
  • Radiographic studies (CT, MRI)
• Management:
  • Surgical intervention:
    • Divide fistula
    • Resect diseased bowel
    • Débride and close bladder opening
  • Postoperative Care:
    • Foley catheter for 10–14 days

Enterogenital Fistulas

• More common in women.
• Common Sites: Rectovaginal fistulas.
• Symptoms:
  • Malodorous vaginal discharge
  • Passage of air or stool via vagina
• Management:
  • Divide fistula tract
  • Primary closure of genital tract opening
  • Resect diseased bowel
  • Consider reproductive implications in women of childbearing age.

Enterocutaneous Fistulas

• Spontaneous fistulas are rare and indicate severe disease.
• Postoperative fistulas are more common, often from anastomotic leaks.
• Management:
  • Supportive care: Nutritional optimization, wound care.
  • Medical therapy: Immunomodulators, biologics.
  • Surgical intervention if:
    • Distal obstruction
    • High-output fistula
    • Difficult wound management

Perforations: Abscesses and Free Perforation

Abscesses

• Occur in up to one-third of patients.
• Symptoms may be minimal due to immunosuppression.
• Signs:
  • Abdominal pain, tenderness
  • Fever
  • Ileus or obstruction
  • Palpable mass
• Diagnosis:
  • Cross-sectional imaging (CT scan)
• Management:
  • Percutaneous drainage if feasible.
  • Medical therapy: Resuscitation, antibiotics, nutritional support.
  • Surgical drainage is rarely required.

Free Perforation

• Rare but serious; requires immediate attention.
• Common in:
  • Toxic colitis
  • Distal obstruction
  • Cancer
  • Postoperative complications
• Symptoms may be subtle in immunosuppressed patients.
• Diagnosis:
  • Abdominal radiograph showing free air.
  • CT scan for detailed assessment.
• Management:
  • Emergent surgical exploration
  • Resuscitation
  • Broad-spectrum antibiotics
  • Stress-dose steroids if applicable
  • Surgical Approach:
    • Débridement and primary repair for gastric/duodenal perforations.
    • Resection and anastomosis for jejunal/ileal perforations.
    • Proximal diversion if patient is unstable or immunosuppressed.

Other Issues in Surgical Management

Crohn Disease of the Duodenum

• Symptoms:
  • Dyspepsia, epigastric pain
  • Anorexia
  • Obstructive symptoms (nausea, vomiting, weight loss)
• Lesions:
  • Inflammatory lesions
  • Strictures
  • Fistulas
• Risk: Increased chance of duodenal cancer with long-standing disease.
• Management:
  • Medical therapy similar to distal Crohn disease.
  • Nutritional support
  • Drain abscesses (usually percutaneously).
  • Surgical Interventions:
    • Fistula takedown
    • Heineke-Mikulicz technique for closure
    • Bypass procedures (duodenojejunostomy, gastrojejunostomy)

Ureteral Obstruction

• Causes:
  • Stone formation post-terminal ileum resection.
  • Acalculous obstruction from adjacent inflammation.
• Symptoms:
  • Urinary urgency and frequency
  • Flank pain
  • Fever
  • Palpable abdominal or flank mass
• Diagnosis:
  • Urinalysis (often normal)
  • Imaging showing ureteral stenosis and dilation
• Management:
  • Medical therapy for Crohn disease.
  • Ureteral stenting for significant obstruction.
  • Percutaneous drainage of abscesses.
  • Surgical intervention (resection and ureterolysis) if nonoperative measures fail.

Postoperative Care

• Similar to other gastrointestinal surgeries.
• Nasogastric suction typically unnecessary for distal procedures.
• Stress-dose steroids for patients on long-term steroids; taper gradually.
• Monitor for complications and promote recovery.

Long-Term Management

• Disease Recurrence:
  • 80% show endoscopic recurrence within 1 year post-resection.
  • 60% experience symptomatic recurrence within 10 years.
  • Higher recurrence after intestinal flow restoration in diverted patients.

• Prevention Strategies:

  • Risk stratification

    

  • Tailored medical therapy

  • Regular monitoring and follow-up.

  

Risk Factors for Recurrence

• Early age at disease onset
• Penetrating disease phenotype
• Smoking
• Extensive disease (>100 cm or multiple sites)
• Genetic factors (e.g., NOD2/CARD15 mutation)

• Rutgeerts Score:

  • Endoscopic scoring postoperatively.
  • Scores <2: Low recurrence risk (<10%).
  • Scores 3–4: High recurrence risk (50–100%).

  

Medications to Prevent Recurrence

• 5-Aminosalicylates
• 6-Mercaptopurine/Azathioprine
• Biologic Agents:
  • Infliximab may be more effective in preventing recurrence.
• Smoking Cessation:
  • Smoking increases recurrence risk by 2.5 times.
  • Strongly recommended for all patients.

Cancer Surveillance

• Increased Cancer Risk in areas of chronic inflammation:
  • Small intestine
  • Colon
• Other Cancers with higher incidence:
  • Squamous cell carcinoma of anus and skin
  • Duodenal neoplasia
  • Testicular cancer
• Medication Risks:
  • Thiopurines (e.g., azathioprine) associated with increased risk of lymphoproliferative disorders.
• Surveillance Recommendations:
  • Regular endoscopic evaluations.
  • Awareness of heightened cancer risk for early detection.

Conclusion

Understanding the complications associated with small bowel Crohn disease is crucial for effective management. Stricturing and penetrating diseases often necessitate surgical intervention, tailored to the patient's specific condition and disease behavior. Long-term management focuses on preventing recurrence through risk stratification, appropriate medical therapy, and regular monitoring. Awareness of increased cancer risks underscores the importance of vigilant surveillance in patients with Crohn disease.