Investigation of New Pancolitis
A comprehensive diagnostic approach for new pancolitis should include clinical evaluation, laboratory tests, stool studies, endoscopy with biopsies, and imaging to determine the cause and extent of inflammation. 1
Initial Clinical Assessment
History
- Stool frequency and consistency
- Presence of urgency or tenesmus
- Rectal bleeding
- Abdominal pain
- Systemic symptoms (malaise, fever, weight loss)
- Recent travel history
- Medication use
- Family history of IBD
- Extraintestinal manifestations (joint, skin, eye) 1
Physical Examination
- Vital signs (pulse, blood pressure, temperature)
- Weight and height
- Abdominal examination for tenderness and distension
- Perianal inspection
- Digital rectal examination 1
Laboratory Investigations
Essential Blood Tests
- Full blood count (FBC)
- Electrolytes
- Liver and renal function tests
- Iron studies
- Vitamin D level
- Inflammatory markers (ESR or CRP) 1
Stool Studies
- Microbiological testing for infectious diarrhea
- Specific testing for Clostridium difficile toxin
- Additional tests for parasites if indicated by travel history
- Fecal calprotectin (sensitive marker of intestinal inflammation) 1
Endoscopic Evaluation
Sigmoidoscopy
- Initial assessment for mild to moderate disease
- Macroscopic features to look for: loss of vascular pattern, granularity, friability, and ulceration of rectal mucosa
- Rectal biopsy should be taken even if no macroscopic changes 1
Colonoscopy
- Preferable to sigmoidoscopy for mild to moderate disease to assess extent
- For suspected severe disease, defer full colonoscopy due to perforation risk
- Terminal ileal intubation and biopsy to document extent and exclude Crohn's disease
- Look for distribution pattern (continuous vs. patchy)
- Assess for backwash ileitis, rectal sparing, or caecal patch 1
Imaging Studies
Plain Abdominal Radiography
- Essential in severe disease to exclude colonic dilatation (>5.5 cm)
- Helps assess disease extent in UC
- Can identify proximal constipation or small bowel dilatation 1
Additional Imaging
- Small bowel radiology (follow-through or enterography) if Crohn's disease is suspected
- CT or MRI may help evaluate complications and disease activity
- Ultrasound can identify thickened bowel loops and abscesses 1
Histopathological Assessment
- Biopsies should be taken from inflamed and non-inflamed areas
- Multiple biopsies from different segments help distinguish between UC and Crohn's disease
- Pathological examination should attempt to define IBD type and identify complications 1
Disease Activity Assessment
- Use standardized scoring systems (Mayo score)
- Assess endoscopic severity
- Document extent of disease (proctitis, left-sided colitis, extensive colitis/pancolitis) 1
Differential Diagnosis Considerations
- Infectious colitis (bacterial, viral, parasitic)
- Inflammatory bowel disease (UC vs. Crohn's)
- Ischemic colitis
- Drug-induced colitis
- Radiation colitis
- Diversion colitis 2
Special Considerations
- In severe disease, joint medical and surgical management is appropriate
- Daily monitoring of vital signs and physical examination in severe cases
- Stool chart to record number and character of bowel movements
- Regular measurement of laboratory parameters (every 24-48 hours in severe disease)
- Daily abdominal radiography if colonic dilatation is detected 1
Common Pitfalls to Avoid
- Delaying treatment while awaiting stool microbiology results in severe disease
- Performing full colonoscopy in severe disease (increased perforation risk)
- Failing to consider Cytomegalovirus infection in immunocompromised patients or steroid-refractory cases
- Overlooking C. difficile infection, which can mimic or exacerbate IBD
- Not considering alternative explanations for symptoms in known IBD patients 1
Remember that pancolitis is associated with more severe disease, higher rates of colorectal cancer, and increased likelihood of colectomy, making thorough investigation crucial for appropriate management 3.