60 years old male present with history of passing blood and mucus diarrhea, more than four episodes, more than five episodes per day, for past nearly more than 10 years. Now he came with, he has done already endoscopy 10 years back, which showed moderate pangastritis, and colonoscopy showed left-sided colitis. What may be the cause and how to work up for this patient?
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"ulcerative colitis" AND "left-sided" AND diagnosis
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Clinical Analysis: 60-Year-Old Male with Chronic Bloody Mucus Diarrhea + Left-Sided Colitis + Pangastritis
Most Likely Diagnosis
The clinical picture strongly points to Ulcerative Colitis (UC) - specifically left-sided UC (distal colitis), with the gastric findings representing upper GI involvement, which can occur in IBD (more commonly in Crohn's disease but also in UC as "IBD-associated gastritis" or "backwash" equivalent).
Key clinical pointers in this case:
- Chronic bloody + mucus diarrhea for >10 years
-
5 episodes/day (fulfills "moderate disease" criteria per Rosen's: >4 stools/day)
- Left-sided colitis on colonoscopy - consistent with UC pattern (rectum extending proximally in a continuous fashion)
- Moderate pangastritis on endoscopy - raises the possibility of Crohn's disease (which can involve the entire GI tract from esophagus to anus) or IBD-associated gastritis
Differential Diagnosis to Consider
| Condition | Supporting Features | Against |
|---|---|---|
| Ulcerative Colitis (Left-sided) | Continuous mucosal inflammation, left-sided, bloody mucus diarrhea, chronic course | Gastric involvement (rare but described) |
| Crohn's Disease (Colonic ± upper GI) | Pangastritis (upper GI involvement), chronic course, mucus | Typically skip lesions, UC pattern was "left-sided colitis" |
| Infectious Colitis (chronic) | Bloody diarrhea, mucus | Typically self-limiting, not 10+ years |
| Ischemic Colitis | Left-sided distribution (splenic flexure, sigmoid) | Age could fit, but not 10-year chronic course |
| Microscopic Colitis | Chronic watery diarrhea, older age | Usually watery, not bloody |
| Colorectal Cancer | Age 60, chronic colitis raises risk | Not primary cause; complication to screen for |
The combination of pangastritis + left-sided colitis in a 10-year course is most suspicious for Crohn's disease affecting both upper GI and colon, or UC with concomitant H. pylori/NSAID gastritis.
Workup Plan (Systematic Approach)
1. History Refinement
- Nature of stool: blood mixed vs. coating, presence of pus
- Nocturnal diarrhea (suggests IBD > IBS)
- Abdominal pain: perianal disease, fistulae, fissures (points to Crohn's)
- Weight loss, fever, fatigue
- Family history of IBD or colorectal cancer
- Medication history: NSAIDs (can worsen/cause gastritis and colitis), aspirin, steroids
- Travel history, antibiotic use (C. difficile risk)
- Extraintestinal symptoms: joint pain, eye redness, skin lesions, jaundice
2. Physical Examination
- Nutritional status, BMI, signs of malnutrition
- Abdominal tenderness (location tells you disease location)
- Perianal inspection: fissures, fistulae, skin tags (strongly suggests Crohn's)
- Oral ulcers (Crohn's)
- Skin: erythema nodosum, pyoderma gangrenosum
- Eyes: episcleritis, uveitis
- Joints: arthropathy
3. Laboratory Investigations
Blood tests:
- CBC - assess for anemia (iron deficiency from chronic blood loss, B12/folate deficiency), leukocytosis (active disease)
- ESR, CRP - inflammatory markers, monitor disease activity
- Serum albumin - marker of nutritional status and disease severity
- LFTs - screen for primary sclerosing cholangitis (PSC, occurs in 2-7.5% of IBD patients, especially UC)
- Iron studies (serum iron, TIBC, ferritin) - iron deficiency anemia
- Serum B12, folate - if extensive small bowel involvement
- Renal function - baseline
Serologic markers (to differentiate UC vs. Crohn's):
- pANCA (perinuclear antineutrophil cytoplasmic antibody) - positive in ~55% of UC patients
- ASCA (anti-Saccharomyces cerevisiae antibody IgG + IgA) - elevated in 40-70% of Crohn's disease; <15% of UC
- ASCA-positive + pANCA-negative = 55% sensitivity, 93% specificity for Crohn's disease
- Anti-OmpC, anti-CBir1, anti-I2 - associated with Crohn's
Note: Serologic markers support but cannot independently diagnose IBD.
Stool tests:
- Stool culture - rule out infectious colitis (Salmonella, Shigella, Campylobacter, E. coli O157)
- Stool for ova and parasites - Entamoeba histolytica, Giardia
- C. difficile toxin PCR - especially if any antibiotic history
- Fecal calprotectin - elevated in active IBD; useful to monitor disease activity and remission (lower in remission)
- Fecal lactoferrin - marker of intestinal inflammation
4. Endoscopy + Histology (Most Important)
Repeat Colonoscopy with biopsies:
- Assess current extent of disease (it can extend over time - 10-15% of initially left-sided UC progress to pancolitis over 10 years)
- Look for continuous vs. skip lesions (UC = continuous; Crohn's = skip)
- Assess rectal involvement (UC always starts in rectum)
- Biopsies from multiple sites (right colon, transverse, left colon, rectum) - look for:
- Crypt distortion, crypt abscesses, basal plasmacytosis (chronic colitis)
- Granulomas (pathognomonic for Crohn's if present)
- Dysplasia (cancer surveillance after 10 years of colitis - this patient is at risk!)
Repeat Upper GI Endoscopy + biopsies:
- Re-assess pangastritis
- Biopsy for H. pylori (CLO test + histology)
- Look for granulomas in gastric/duodenal biopsies (if present, strongly supports Crohn's disease)
- Evaluate duodenum for Crohn's involvement
Important: After 8-10 years of left-sided UC, dysplasia/colorectal cancer surveillance colonoscopy is mandatory. Risk of CRC increases significantly after 10 years.
5. Imaging
- CT enterography or MRI enterography - to evaluate small bowel for Crohn's involvement (strictures, fistulae, skip lesions), which cannot be seen on colonoscopy
- CT abdomen/pelvis - if complications suspected (abscess, perforation, stricture)
- Barium studies have been largely supplanted by CT/MRI enterography
6. Additional Tests Based on Findings
- Bone density (DEXA scan) - if on long-term steroids; IBD patients are at risk for osteoporosis
- Hepatobiliary workup (MRCP if LFTs abnormal) - for primary sclerosing cholangitis
- Colonoscopy + chromoendoscopy - if dysplasia surveillance is needed (standard of care after 10 years of colitis)
Disease Activity Severity Classification (Rosen's Emergency Medicine)
| Severity | Criteria |
|---|---|
| Mild UC | <4 stools/day, may have some blood, no systemic toxicity |
| Moderate UC | >4 stools/day, minimal signs of toxicity |
| Severe UC | >6 bloody stools/day + systemic toxicity (fever, tachycardia, anemia, elevated ESR) |
This patient's >5 episodes/day with bloody mucus = moderate disease.
Key Differentiating Point: UC vs. Crohn's
| Feature | Crohn's Disease | Ulcerative Colitis |
|---|---|---|
| GI involvement | Entire GI tract (esophagus to anus) | Colon only |
| Pattern | Skip lesions | Continuous from rectum |
| Transmural inflammation | Yes | No (superficial) |
| Fistulae/abscesses | Yes | No |
| Perianal disease | Yes | No |
| pANCA | 20% | 55% |
| ASCA | 40-70% | <15% |
| Granulomas on biopsy | Yes (pathognomonic) | No |
The pangastritis is the key clue here - if biopsies from the stomach show granulomas, this shifts the diagnosis firmly to Crohn's disease.
Cancer Surveillance Note
This patient has had left-sided colitis for >10 years - this puts him in the category requiring surveillance colonoscopy for colorectal cancer, as the risk of CRC increases significantly after 8-10 years of IBD. Per guidelines, he should undergo chromoendoscopy with targeted biopsies or systematic biopsy surveillance.
Sources:
- Goldman-Cecil Medicine, 26th ed. (Ulcerative Colitis - Diagnosis, Laboratory Findings, Serologic Markers)
- Rosen's Emergency Medicine, 9th ed. (IBD - Clinical Features, Severity Classification)
- Yamada's Textbook of Gastroenterology, 7th ed. (Left-sided UC - Treatment)
- ACG Clinical Guideline Update: Ulcerative Colitis in Adults, 2025 [PMID: 40701556]
- AGA Living Clinical Practice Guideline on Pharmacological Management of Moderate-to-Severe UC, 2024 [PMID: 39572132]
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