Select the symptom severity in each category to visualize the cumulative PDAI perianal activity index.
Guidelines & Evidence
Clinical Details
Section 1
When to Use
When to Use
Diagnosis and severity assessment of pouchitis in patients with an Ileal Pouch-Anal Anastomosis (IPAA)
Standardized monitoring of patients following proctocolectomy for Ulcerative Colitis
To guide antibiotic therapy (Ciprofloxacin/Metronidazole) vs. chronic inflammatory management
Defining Pouchitis
Pouchitis is the most common long-term complication of IPAA. A high PDAI confirms the diagnosis by integrating clinical symptoms with endoscopic and histological objective data.
Section 2
Formula & Logic
The 3 Scoring Triads (0–18 pts total)
01
Symptoms (0–6 pts): Stool frequency, urgency, fever, and rectal bleeding.
02
Endoscopy (0–6 pts): Oedema, friability, ulceration, and loss of vascular pattern in the pouch.
03
Histology (0–6 pts): Acute inflammation (neutrophils) and ulceration.
Diagnostic Threshold
Score ≥ 7
Definitive Pouchitis
Score < 7
Asymptomatic or non-pouchitis abdominal pain
Common Misdiagnosis
Up to 25% of patients with "Pouchitis" symptoms actually have Cuffitis (inflammation of the remaining rectal cuff) or IPS (Irritable Pouch Syndrome), emphasizing the need for the full PDAI.
Section 3
Pearls/Pitfalls
Antibiotic Responsiveness
Acute pouchitis typically responds within 14 days to Metronidazole or Ciprofloxacin. If the PDAI remains high despite these antibiotics, it is classified as "Antibiotic-Refractory" or "Chronic" pouchitis, requiring escalation to biologicals (e.g., Vedolizumab).
The Crohn's of the Pouch
A high PDAI with deep ulcerations or "prepouch ileitis" (inflammation extending into the afferent limb) is highly suspicious for de-novo Crohn's disease of the pouch.
Clinical Pearls
VSL#3 (High-potency probiotic) is effective for maintaining remission in patients with recurrent pouchitis
PDAI is the gold standard for clinical trials, but many clinicians use the "Simplified PDAI" (Symptoms + Endoscopy only) in everyday practice
Smoking is actually a protective factor for pouchitis (similar to UC), unlike its detrimental role in Crohn's
Section 4
Next Steps
Management Pathways
01
Score ≥ 7: Start Ciprofloxacin (500mg BID) or Metronidazole (500mg TID) for 2 weeks.
02
Refractory: Evaluate for CMV, C. diff, or ischaemia; consider Vedolizumab or Infliximab.
Complementary Tools
Wexner Incontinence Score
Montreal Classification (UC)
Geboes Score (Histology)
Section 5
Evidence Appraisal
The Foundational System
Pouchitis after ileal pouch-anal anastomosis: a Pouchitis Disease Activity Index.
Sandborn WJ et al. • Mayo Clinic Proceedings. 1994;69(5):409-15. The first comprehensive description of the PDAI.
Developed by William Sandborn and his colleagues. As the number of IPAA procedures increased in the 90s, they recognized that "symptoms alone" led to over-prescription of antibiotics, necessitating this balanced clinical-pathological index.
