What is the diagnosis and treatment for a patient experiencing back pain, constipation, ribbon-like stools, lower right quadrant abdominal pain, pain with prolonged sitting, night sweats, stool discharge, and weight loss after childbirth?

Diagnostic Evaluation and Management

Based on this constellation of alarm features—particularly the combination of ribbon-like stools, unintentional weight loss, night sweats, lower right quadrant pain, and discharge in stools—colorectal malignancy must be urgently excluded with colonoscopy, as these symptoms strongly suggest either colorectal cancer or inflammatory bowel disease rather than a benign functional disorder. 1, 2

Critical Red Flags Present

This patient presents with multiple alarm features that mandate immediate investigation rather than empiric treatment:

• Ribbon-like stools indicate a possible obstructing lesion in the colon, most concerning for colorectal cancer 1, 3
• Unintentional weight loss is a cardinal alarm feature requiring exclusion of malignancy and constitutes an absolute indication for colonoscopy regardless of age 1, 2, 4
• Night sweats combined with weight loss suggest systemic disease, potentially malignancy or inflammatory bowel disease 1
• Discharge in stools (likely mucus or blood) indicates mucosal pathology requiring endoscopic evaluation 1
• Lower right quadrant pain with these features raises concern for cecal pathology, inflammatory bowel disease (particularly Crohn's disease), or right-sided colon cancer 1

Immediate Diagnostic Workup Required

Laboratory Studies (Urgent)

• Complete blood count to assess for anemia (from occult bleeding) and inflammatory markers 1, 5
• Erythrocyte sedimentation rate and C-reactive protein to evaluate for inflammatory bowel disease 1, 4
• Comprehensive metabolic panel including albumin to assess nutritional status and liver function 1
• Fecal calprotectin to screen for inflammatory bowel disease, though colonoscopy is still mandatory given alarm features 2
• Celiac serology (tissue transglutaminase IgA with total IgA) as celiac disease can present with weight loss and altered bowel habits 2, 6

Imaging and Endoscopy (Urgent)

• Colonoscopy with biopsies is mandatory and should be performed urgently (within 2 weeks) given the combination of ribbon-like stools, weight loss, and right lower quadrant pain 1, 2
• CT abdomen and pelvis with IV contrast should be obtained if there is concern for bowel obstruction, abscess, or to stage potential malignancy 1, 3
• Biopsies during colonoscopy must include right and left colon to exclude microscopic colitis and inflammatory bowel disease even if mucosa appears normal 2

Differential Diagnosis (In Order of Urgency)

Primary Concerns Requiring Urgent Exclusion

1. Colorectal cancer: Ribbon-like stools suggest luminal narrowing, weight loss and night sweats indicate systemic disease, and right lower quadrant location is consistent with cecal or ascending colon malignancy 1, 2, 5

2. Inflammatory bowel disease (Crohn's disease): Right lower quadrant pain, systemic symptoms (night sweats, weight loss), and altered bowel habits are classic for Crohn's disease involving the terminal ileum and cecum 1, 7

3. Small bowel obstruction: Constipation, pain with sitting, and ribbon-like stools could indicate partial obstruction, though the presence of any stool passage makes complete obstruction less likely 1, 3

Secondary Considerations

1. Diverticular disease with complications: Can cause lower quadrant pain and altered bowel habits, though right-sided diverticulitis is less common 1, 7

2. Infectious colitis: Discharge in stools could represent infectious etiology, though chronic nature and weight loss make this less likely 1

Why IBS is NOT the Diagnosis

IBS should NOT be diagnosed in this patient despite some overlapping symptoms, because:

• Weight loss is an alarm feature that excludes IBS diagnosis until organic disease is ruled out 1, 2, 4
• Night sweats are not consistent with IBS and suggest systemic inflammatory or malignant process 1
• Ribbon-like stools suggest structural pathology rather than functional disorder 1
• The British Society of Gastroenterology explicitly states that IBS diagnosis requires absence of alarm symptoms, and this patient has multiple alarm features 1

Management Algorithm

Immediate Actions (Within 24-48 Hours)

1. Order urgent laboratory studies as outlined above 1
2. Refer for urgent colonoscopy (within 2 weeks) 2
3. Consider CT abdomen/pelvis if obstruction is suspected or to evaluate extent of disease 1, 3

If Colonoscopy Reveals Inflammatory Bowel Disease

• Initiate treatment with mesalamine for mild-to-moderate disease 8
• Consider corticosteroids (prednisone) for moderate-to-severe disease 9
• Refer to gastroenterology for consideration of immunomodulators (azathioprine) for maintenance therapy 10
• Monitor for complications including strictures, fistulas, and abscesses 1

If Colonoscopy Reveals Malignancy

• Urgent surgical consultation for resection 1
• Staging with CT chest/abdomen/pelvis 1
• Multidisciplinary tumor board discussion for treatment planning 1

If Colonoscopy is Normal

• Review biopsies for microscopic colitis 2
• Consider small bowel imaging (CT or MR enterography) to evaluate for small bowel Crohn's disease 1
• Reassess for other causes of weight loss and systemic symptoms 5

Critical Pitfalls to Avoid

• Do not empirically treat as IBS without excluding organic disease when alarm features are present—this delays diagnosis of potentially life-threatening conditions 1, 2, 4
• Do not rely on fecal occult blood testing alone—colonoscopy is mandatory regardless of fecal occult blood results when alarm features are present 1
• Do not delay colonoscopy for therapeutic trials of fiber, antispasmodics, or dietary modifications when alarm features are present 1
• Do not attribute symptoms to postpartum changes without thorough evaluation—while some functional symptoms can occur postpartum, alarm features mandate investigation 2