What is the best course of action for managing a patient with chronic diarrhea, acid reflux, and recent onset of hematochezia, with lab results indicating elevated inflammatory markers?

Urgent Endoscopic Evaluation and Inflammatory Bowel Disease Workup Required

This patient requires urgent colonoscopy with biopsies to evaluate for inflammatory bowel disease (IBD), given the constellation of nocturnal diarrhea, hematochezia, elevated inflammatory stool markers, and prior endoscopic findings of colonic erosions. 1, 2, 3

Immediate Diagnostic Priorities

Endoscopic Assessment is Essential

• Colonoscopy with biopsies from right and left colon (not rectal) should be performed urgently to exclude ulcerative colitis, Crohn's disease, and microscopic colitis, particularly given the new-onset hematochezia and prior sigmoid erosions 1
• The presence of nocturnal diarrhea (awakening 7 times nightly) is a red flag indicating organic disease rather than functional disorder 2, 3, 4
• Hematochezia in the setting of chronic diarrhea mandates exclusion of colorectal cancer and IBD 1

Stool Markers Strongly Suggest Active Inflammation

• Elevated MMP-9, lactoferrin, beta-defensin 2, and eosinophil protein X indicate significant intestinal inflammation consistent with IBD 1, 2
• Low secretory IgA suggests mucosal immune dysfunction 2
• These biomarkers, combined with symptoms, warrant endoscopic confirmation rather than empiric treatment 1

Additional Laboratory Evaluation Needed

Complete IBD Workup

• Obtain CBC, CRP, ESR, comprehensive metabolic panel, albumin, and iron studies if not recently done 1, 3
• The elevated LDH, AST, ALT, and ferritin require correlation with inflammatory activity versus other pathology 1
• High B12 may indicate small bowel bacterial overgrowth or ileal disease 3

Rule Out Infectious Causes

• Stool culture, ova and parasites, Giardia antigen, and Clostridium difficile toxin testing should be performed before initiating immunosuppressive therapy 1, 2
• This is critical even though symptoms are chronic, as infection can mimic or coexist with IBD 1

Management Approach Based on Endoscopic Findings

If Ulcerative Colitis is Confirmed

• Active distal colitis requires combination therapy with topical mesalazine or topical steroid plus oral mesalazine or corticosteroids 1
• For moderate-to-severe disease not responding to oral therapy, admission for intravenous corticosteroids (prednisolone 40 mg daily equivalent) with joint medical-surgical management 1
• Monitor daily with vital signs, stool charts, CBC, CRP, and abdominal radiographs if colonic dilatation suspected 1

If Crohn's Disease is Confirmed

• Biomarker-guided treatment adjustments are recommended over symptom-based management alone to achieve better long-term outcomes 1
• With fecal calprotectin >150 mg/g (which this patient likely has given elevated lactoferrin), endoscopic assessment guides treatment intensity 1
• Consider small bowel imaging (MR enterography preferred) to assess extent of disease 1

If Microscopic Colitis is Found

• Right and left colon biopsies (not rectal) are essential as this diagnosis requires histologic confirmation 1
• Treatment typically involves budesonide or other anti-inflammatory agents 1

Critical Pitfalls to Avoid

Do Not Delay Endoscopy for Empiric Treatment

• The AGA specifically recommends against empiric treatment adjustment when biomarkers are elevated without endoscopic confirmation 1
• Given hematochezia and prior erosions, malignancy must be excluded 1

Address the Acid Reflux Appropriately

• The esophagitis and gastritis require PPI therapy, but this should not distract from the more urgent lower GI evaluation 1
• Interestingly, PPI therapy may help functional diarrhea through reduction of gastrocolic reflex, but this patient's presentation is clearly organic 5

Consider Bile Acid Diarrhea as Contributing Factor

• If IBD is excluded or only partially explains symptoms, SeHCAT testing or serum 7α-hydroxy-4-cholesten-3-one should be performed 1
• However, the inflammatory markers and hematochezia make primary bile acid diarrhea unlikely 1, 2

Urgent Referral Pathway

• Immediate gastroenterology referral for colonoscopy within days, not weeks 1, 2, 3
• If severe symptoms develop (>6 bloody stools daily, fever, tachycardia), hospital admission for intravenous therapy may be required 1
• Joint medical-surgical consultation should be arranged if severe colitis is confirmed, given 25-30% may require colectomy 1

The combination of nocturnal diarrhea, hematochezia, elevated inflammatory stool markers, and prior colonic erosions creates a clinical picture highly suspicious for IBD requiring urgent diagnostic clarification and treatment initiation. 1, 2, 3