Pouchitis

Pouchitis occurs in approximately 50% of patients following ileal pouch-anal anastomosis (IPAA) for chronic ulcerative colitis (UC) (1,2).

Pouchitis is an idiopathic chronic inflammatory disease that may occur in the ileal pouch after restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) (1,2)

• pouchitis can occur after construction of pouches for either chronic ulcerative colitis or familial adenomatous polyposis - however pouchitis occurs much less frequently in the latter, providing evidence that pouchitis is less related to the structure of the pouch, but is a function of the patients' underlying immune dysregulation interacting with the pouch
• diagnosis of pouchitis is suggested by variable clinical symptoms including increased stool frequency, abdominal cramping, faecal urgency and tenesmus, incontinence, and occasionally rectal bleeding and fever
  • clinical diagnosis should ideally be confirmed by endoscopy and mucosal biopsy of the pouch (2)
    • endoscopic examination shows inflammatory changes that may include:
      • mucosal oedema,
      • granularity,
      • contact bleeding,
      • loss of vascular pattern,
      • haemorrhage,
      • ulceration
  • histologic examination shows:
    • acute inflammation, including neutrophil infiltration and mucosal ulceration superimposed on a background of chronic inflammation including villous atrophy, crypt hyperplasia, and chronic inflammatory cell infiltration
      
      
  • patients with pouchitis can be classified according to disease activity and symptom duration
    • disease activity can be classified as: remission (no active pouchitis); mild-to-moderately active (increased stool frequency, urgency, infrequent incontinence); or severely active (hospitalisation for dehydration, frequent incontinence)
    • symptom duration can be classified as: acute (<= 4 weeks); or chronic (> 4 weeks)
    • Pouchitis Disease Activity Index (PDAI) is a 19 point index of pouchitis activity based on both clinical symptoms and endoscopic and histologic findings (3)
      • active pouchitis is defined as a PDAI >=7 and remission is defined as a PDAI < 7. Clinical response to treatment can also be quantified by reduction in the PDAI (e.g. a reduction in the PDAI score ≥ 3 from baseline)
• management:
  • a systematic review found very low quality evidence suggesting ciprofloxacin may be more effective than metronidazole for acute pouchitis and low quality evidence that VSL#3 (probiotic) may be more effective than placebo for remission maintenance in chronic pouchitis (1)

Reference

1. Nguyen N et al. Treatment and prevention of pouchitis after ileal pouch-anal anastomosis for chronic ulcerative colitis. Cochrane Systematic Review November 2019.
2. Gionchetti P et al. Pouchitis: Clinical Features, Diagnosis, and Treatment. Int J Gen Med. 2021 Jul 24:14:3871-3879.