What is the management approach for abdominal masses in patients with Crohn's disease?

Management of Abdominal Masses in Crohn's Disease

For abdominal masses in Crohn's disease patients, the management approach should prioritize percutaneous drainage of abscesses >3cm combined with appropriate antimicrobial therapy as first-line treatment, followed by consideration of surgical intervention for non-responsive cases or those with signs of sepsis. 1

Initial Assessment

• IV contrast-enhanced CT scan is the recommended first-line imaging modality to evaluate abdominal masses in Crohn's disease, as it can identify abscesses, fistulas, inflammatory masses, and strictures 1, 2
• Point-of-care ultrasonography can be used when CT is unavailable to assess for free intra-abdominal fluid, intestinal distension, or abscesses 1
• MR enterography is preferred for evaluating strictures and differentiating between inflammatory and fibrotic components 1
• Laboratory assessment should include complete blood count, C-reactive protein, and erythrocyte sedimentation rate to assess inflammation 1

Classification of Abdominal Masses in Crohn's Disease

Abdominal masses in Crohn's disease typically fall into several categories:

• Inflammatory masses: Dense mesenteric inflammation adjacent to severe mural inflammation without a well-defined fluid component 1
• Abscesses: Well-defined fluid collections that may be amenable to drainage 1
• Complex fistula formations: Often creating asterisk-shaped complexes tethering multiple bowel loops 1
• Strictures with proximal bowel dilation: Often associated with penetrating disease 1

Management Algorithm

For Abscesses

1. Small abscesses (<3 cm):

   • Treat with intravenous antibiotics targeting gram-negative aerobic and facultative bacilli, gram-positive streptococci, and obligate anaerobic bacilli 1
   • Monitor clinical and biochemical parameters closely 1
   • Be aware of higher recurrence risk, especially if associated with enteric fistulae 1

2. Larger abscesses (>3 cm):

   • Percutaneous drainage under radiological guidance is first-line treatment in hemodynamically stable patients 1
   • Combine with appropriate antimicrobial therapy based on local epidemiology and resistance patterns 1, 2
   • Consider as a bridging procedure before elective surgery to reduce the need for stoma creation and limit intestinal resection in malnourished patients 1

3. Surgical intervention is indicated when:

   • Percutaneous drainage fails 1
   • Patient shows signs of septic shock 1
   • Enteric fistulae are present with persistent clinical evidence of sepsis despite initial treatment 1
   • Free perforation occurs 1

For Inflammatory Masses (Non-abscess)

• Multidisciplinary approach involving gastroenterologists and surgeons 1
• Medical management with intravenous corticosteroids in hemodynamically stable patients 1
• Assess response to steroids by the third day 1
• For non-responders who remain hemodynamically stable, consider rescue therapy with infliximab in combination with a thiopurine, or ciclosporin 1

For Strictures with Masses

• For symptomatic strictures <5 cm, consider endoscopic balloon dilation or surgery depending on local expertise and patient preference 1
• Surgery is mandatory for symptomatic intestinal strictures that don't respond to medical therapy and aren't amenable to endoscopic dilatation 2
• Deferred surgery is preferred for acute small-bowel obstruction without bowel ischemia or peritonitis 1

Nutritional Support

• Total parenteral nutrition should be provided for nutritionally deficient patients unable to tolerate enteral nutrition 1
• This is particularly important when the enteral route is contraindicated, in critically ill patients, or those with high-output fistula or severe intestinal hemorrhage 1
• Preoperative nutritional support is mandatory in severely undernourished patients 1

Important Considerations and Pitfalls

• Avoid routine administration of antibiotics unless there is evidence of superinfection or intra-abdominal abscess 1
• Be aware that preoperative treatments with immunomodulators, anti-TNF-α agents, and steroids increase the risk of intra-abdominal sepsis in patients requiring emergency surgery 1
• When penetrating disease is present, look for an inflamed and stenotic bowel segment with upstream dilation, as these are nearly always present 1
• The term "phlegmon" should be avoided due to its ambiguous definition; instead, use "inflammatory mass" for non-drainable inflammation or "abscess" for collections with a drainable component 1
• Consider infliximab for penetrating ileocecal Crohn's disease only after adequate resolution of intra-abdominal abscesses 1