What is the next best step in managing a 31-year-old woman with progressive abdominal discomfort, diarrhea, constipation, bloating, and flatulence, with lab results showing anemia, elevated liver enzymes (AST, ALT), and inflammatory markers (erythrocyte sedimentation rate, lactoferrin), and a normal physical examination?

Colonoscopy is the Next Best Step in Management for This Patient

Based on the clinical presentation and laboratory findings, colonoscopy (option B) is the next best step in management for this patient. 1

Rationale for Colonoscopy

Key Clinical and Laboratory Findings Suggesting IBD:

• Progressive abdominal discomfort with alternating diarrhea and constipation
• Bloating and flatulence
• Symptoms worsen with stress and eating, improve with defecation
• Laboratory abnormalities:
  • Anemia (hemoglobin 10 g/dL, hematocrit 30%)
  • Elevated liver enzymes (AST 91 U/L, ALT 112 U/L)
  • Elevated inflammatory markers (ESR 49 mm/hr)
  • Positive fecal lactoferrin

Diagnostic Algorithm:

1. Initial assessment: Patient presents with IBS-like symptoms but has concerning laboratory findings
2. Inflammatory markers: Elevated ESR and positive fecal lactoferrin strongly suggest inflammatory bowel disease rather than IBS 2, 3
3. Next step: Colonoscopy with biopsies to:
   • Confirm or rule out inflammatory bowel disease
   • Assess disease extent and severity if IBD is present
   • Obtain tissue for histological examination

Why Other Options Are Less Appropriate

Fiber supplements (Option A):

• Inappropriate when inflammatory markers are elevated
• May worsen symptoms in patients with IBD
• Fails to address the need for definitive diagnosis 1

Biofeedback and antidepressants (Option C):

• Primarily used for functional disorders after organic disease has been excluded
• Not indicated as first-line when objective evidence of inflammation exists 1

Broad-spectrum antibiotics (Option D):

• Not indicated without confirmed infection
• Would not address the underlying inflammatory process
• Could potentially worsen symptoms if IBD is present 1

Supporting Evidence

The British Society of Gastroenterology guidelines recommend colonoscopy for patients with suspected IBD, particularly when fecal inflammatory markers are positive 1. The AGA guidelines specifically state that individuals presenting with chronic diarrhea with intermediate to high suspicion for underlying IBD should undergo colonoscopy 1.

The presence of elevated inflammatory markers (ESR 49 mm/hr) and positive fecal lactoferrin are particularly significant. Fecal lactoferrin is a marker of intestinal inflammation that helps distinguish between inflammatory and non-inflammatory conditions 3, 4. A meta-analysis showed that normal inflammatory markers essentially exclude IBD, but elevated markers like in this case strongly suggest it 4.

Important Clinical Considerations

• The patient's age (31 years) and presentation with anemia, elevated liver enzymes, and inflammatory markers make IBD more likely than IBS
• Early diagnosis of IBD is critical to prevent disease progression and complications 5
• Colonoscopy allows for direct visualization of the mucosa and tissue sampling, which are essential for accurate diagnosis and treatment planning
• If IBD is confirmed, appropriate therapy can be initiated promptly to reduce inflammation and prevent complications

Colonoscopy represents the gold standard for diagnosing IBD and will provide the most definitive information to guide appropriate treatment for this patient with concerning clinical and laboratory findings.