Could this patient's symptoms be related to inflammatory bowel disease (IBD)?

Inflammatory Bowel Disease: Diagnosis and Management

Inflammatory bowel disease (IBD) is characterized by chronic intestinal inflammation resulting from host-microbial interactions in genetically susceptible individuals, with two major forms - Crohn's disease (CD) and ulcerative colitis (UC). 1 The diagnosis and management of IBD require careful evaluation to distinguish it from functional gastrointestinal disorders and to address both intestinal and extra-intestinal manifestations.

Diagnostic Approach

Clinical Presentation

• Abdominal symptoms: diarrhea, abdominal pain, bloody stools, and vomiting 1
• Extra-intestinal manifestations:
  • Ocular: episcleritis, scleritis, uveitis 2
  • Dermatological: erythema nodosum, pyoderma gangrenosum 2
  • Oral: deep ulcerations, pseudopolyps, labial/buccal swelling 2
  • Musculoskeletal: spondyloarthritis (axial or peripheral) 2

Diagnostic Testing

1. Laboratory tests:

   • Complete blood count
   • C-reactive protein (CRP)/ESR
   • Fecal calprotectin - crucial for distinguishing IBD from IBS 2

2. Serological markers:

   • p-ANCA: present in 68% of UC patients vs. 21% in CD 3
   • ASCA and other antibodies may help distinguish CD from UC 4

3. Endoscopic evaluation:

   • Colonoscopy with biopsies when fecal calprotectin is elevated (≥250 μg/g) 2
   • Histological assessment for inflammation

Distinguishing IBD from IBS

The diagnostic algorithm should follow these steps:

1. Assess for alarm symptoms (weight loss, nocturnal symptoms, family history of IBD/colorectal cancer)
2. Measure fecal calprotectin:
   • If ≥250 μg/g: proceed to colonoscopy
   • If indeterminate (100-249 μg/g): repeat test after stopping NSAIDs and PPIs 2
3. Consider overlapping functional symptoms:
   • Up to 39% of IBD patients may have concurrent IBS-like symptoms 2
   • Functional symptoms significantly impact quality of life in IBD patients 2

Management Approach

Treatment of Intestinal Inflammation

• 5-aminosalicylic acid (5-ASA)
• Immunomodulators
• Biologic therapies 5

Treatment of Extra-intestinal Manifestations

1. Ocular manifestations:

   • Episcleritis: May self-resolve; topical/systemic NSAIDs or topical corticosteroids
   • Scleritis/uveitis: Treatment guided by ophthalmologist; includes topical/systemic corticosteroids, immunosuppressants, anti-TNF agents 2

2. Dermatological manifestations:

   • Erythema nodosum: Usually responds to treatment of underlying IBD; systemic corticosteroids for severe cases
   • Resistant cases: azathioprine, infliximab, or adalimumab 2

3. Musculoskeletal manifestations:

   • IBD-associated spondyloarthritis should be classified according to ASAS criteria
   • Disease activity should be assessed using ASDAS-CRP 2
   • Treatment decisions should be shared between patient and physician 2

Management of Overlapping Functional Symptoms

When IBD is in remission but functional symptoms persist:

1. Consider non-inflammatory mechanisms:

   • Small intestinal bacterial overgrowth (SIBO)
   • Bile acid diarrhea (BAD)
   • Functional changes in motility or absorptive capacity
   • Intestinal dysbiosis
   • Increased intestinal permeability 2

2. Treatment options:

   • Dietary interventions (low FODMAP diet)
   • Antispasmodics for acute pain
   • Low-dose tricyclic antidepressants for chronic pain
   • Probiotics may be considered
   • Pelvic floor therapy for defecatory disorders
   • Physical exercise should be encouraged 2, 6

Common Pitfalls and Caveats

1. Overdiagnosis of IBS in IBD patients:

   • CDAI (Crohn's Disease Activity Index) may be elevated in both IBS and IBD patients 2
   • Always exclude active inflammation before attributing symptoms to functional disorders

2. Overlooking extra-intestinal manifestations:

   • Extra-intestinal symptoms may precede intestinal symptoms
   • Monitor for "red flags" that indicate need for specialist referral 2

3. Misattributing functional symptoms to active IBD:

   • Up to 27% of UC patients with both endoscopic and histologic healing may still have increased stool frequency 2
   • Overtreatment of intestinal inflammation for symptoms due to functional pathophysiology increases risk of adverse effects without symptomatic benefit 2

4. Ignoring psychological factors:

   • Psychological distress is more dependent on GI symptoms in IBD compared to IBS 2
   • Anxiety and reduced vitality are independent predictors for functional symptoms in IBD patients in remission 2

By following this structured approach to diagnosis and management, clinicians can effectively address both the inflammatory and functional components of IBD, improving patient outcomes and quality of life.