What is the next step in managing a 41-year-old female with chronic diarrhea and elevated fecal calprotectin (60.7)?

Management of Chronic Diarrhea with Mildly Elevated Fecal Calprotectin

For a 41-year-old female with chronic diarrhea and a fecal calprotectin of 60.7 μg/g, the next step should be to treat for Irritable Bowel Syndrome (IBS) in primary care, as this level falls below the threshold that would warrant immediate gastroenterology referral. 1

Interpreting the Fecal Calprotectin Result

The patient's fecal calprotectin level of 60.7 μg/g provides important diagnostic information:

• According to the British Society of Gastroenterology guidelines, fecal calprotectin levels <100 μg/g in patients with chronic diarrhea suggest IBS is likely 1
• This level falls within the range where IBS is more probable than inflammatory bowel disease (IBD)
• The negative predictive value of low calprotectin levels (<50-100 μg/g) for ruling out IBD is high 2

Management Algorithm

1. Initial management: Treat as IBS in primary care setting

   • Begin IBS-specific therapies based on predominant symptoms
   • Consider dietary modifications (low FODMAP diet trial)
   • Antispasmodics for abdominal pain if present

2. Additional considerations:

   • Rule out other differential diagnoses that can present with normal/mildly elevated calprotectin:
     • Bile acid malabsorption
     • Microscopic colitis
     • Medication-induced diarrhea
     • Celiac disease (can have false-negative calprotectin) 3

3. Follow-up plan:

   • If symptoms persist or worsen despite appropriate IBS management:
     • Consider repeat fecal calprotectin testing
     • If calprotectin rises >100 μg/g, refer to gastroenterology
     • If symptoms deteriorate significantly regardless of calprotectin level, refer to gastroenterology 1

Important Caveats and Pitfalls

• Do not rely solely on calprotectin: While useful, it should be interpreted in the context of the entire clinical picture
• Watch for alarm features: If the patient develops rectal bleeding, weight loss, or iron deficiency anemia, refer via suspected cancer pathway regardless of calprotectin level 1, 2
• Consider confounding factors: NSAID use within the past 6 weeks can falsely elevate calprotectin levels 1, 3
• Remember diagnostic limitations: Fecal calprotectin is not sensitive enough for excluding colorectal cancer 1, 4
• Be aware of false negatives: Conditions like celiac disease can present with normal calprotectin levels 3

Additional Testing to Consider

• Complete blood count, CRP, and celiac serology should be performed if not already done 1
• Consider stool culture to rule out infectious causes 1
• If symptoms suggest bile acid malabsorption, consider SeHCAT testing or empiric trial of bile acid sequestrants

By following this approach, you can appropriately manage this patient with chronic diarrhea and mildly elevated fecal calprotectin, while remaining vigilant for signs that would necessitate specialist referral or further investigation.