Pouchitis

Pouchitis is an inflammatory condition of the ileal reservoir (pouch) that can occur after restorative proctocolectomy with ileal pouch–anal anastomosis. Diagnosis is based on a combination of clinical symptoms (e.g., increased stool frequency and fecal urgency) and endoscopic and histological findings. Risk factors include underlying ulcerative colitis. The etiology is multifactorial, involving a genetic predisposition, gut microbiota, and immune system dysregulation. Pouchitis can be classified based on duration (acute vs. chronic), response to antibiotics (responsive, dependent, or refractory), or etiology (idiopathic vs. secondary). Management for acute pouchitis typically involves a 2-week course of ciprofloxacin or metronidazole. Chronic pouchitis requires more complex strategies, including maintenance antibiotics, probiotics, budesonide, or advanced therapies such as vedolizumab or anti-TNF agents, depending on the subtype. Secondary pouchitis is managed by treating the underlying trigger, such as infections or medication use. Complications include progression to chronic disease, Crohn disease of the pouch, and pouch failure.

Pouchitis is an inflammatory condition of the ileal reservoir that can occur after restorative proctocolectomy with ileal pouch–anal anastomosis. ^[1]

• ∼ 70–80% of patients with an ileal pouch develop at least one episode of acute pouchitis. ^[2]
• ∼ 60% have more than one episode of acute pouchitis. ^[2]
• ∼ 20% develop chronic pouchitis. ^{[2] [1]}

Epidemiological data refers to the US, unless otherwise specified.

Etiology is multifactorial, e.g., involving a genetic predisposition, gut microbiota, immune system dysregulation, and ischemic factors. ^[1]

Risk factors ^[1]

• Underlying ulcerative colitis
• Extraintestinal manifestations, especially:
  • Primary sclerosing cholangitis (PSC)
  • Arthralgia
• Family history of inflammatory bowel disease (IBD)

Children may be at increased risk of developing pouchitis compared to adults. ^[1]

Secondary pouchitis ^[1][3]

Identifiable causes of secondary pouchitis include:

• Infectious pouchitis
  • Clostridioides difficile
  • CMV
• Medication-induced (e.g., NSAID-induced pouchitis)
• Fecal stasis caused by pouch outlet obstruction ^[4]
• Radiation pouchitis caused by pelvic radiation
• Ischemic pouchitis

Pouchitis can be classified in several different ways; a combined classification is often used in practice. ^[3]

• Based on duration
  • Acute pouchitis: Symptoms respond to therapy within 2–4 weeks. ^[2]
  • Chronic pouchitis: Symptoms persist for ≥ 4 weeks despite adequate therapy or > 3–4 acute episodes per year.
• Based on etiology
  • Idiopathic pouchitis: no identifiable cause
  • Secondary pouchitis: identifiable cause
• Based on response to antibiotics
  • Antibiotic-responsive pouchitis: good response to antibiotic therapy (based on symptoms and/or endoscopy)
  • Antibiotic-dependent pouchitis: initial good response to antibiotic therapy with recurrent relapses upon discontinuation
  • Antibiotic-refractory pouchitis: minimal or no response to a 2–4-week course of antibiotic therapy

Acute pouchitis frequently progresses to chronic pouchitis. ^[1]

Symptoms are nonspecific. ^[3]

• Increased stool frequency
• Fecal urgency
• Incontinence or nocturnal seepage
• Abdominal cramping and/or pelvic pain

Bleeding is uncommon and may indicate cuffitis or pouch prolapse. Systemic symptoms (e.g., fever, night sweats, weight loss) may indicate an infectious etiology, penetrating Crohn disease, or an anastomotic leak. ^[1]

A diagnosis is made based on a combination of clinical features and endoscopic findings. Laboratory studies can help assess severity and identify secondary causes. ^[1][3]

Pouchoscopy with biopsy

• Also used for disease monitoring ^[1]
• Endoscopic findings that suggest pouch inflammation include: ^[3]
  • Erythema
  • Friability
  • Altered vascular pattern
  • Erosions and/or ulcers
• Histological findings can confirm the diagnosis and identify secondary causes (e.g., ischemia, immune-mediated pouchitis) ^[3]

Laboratory studies

• Inflammatory markers: can be used as an adjunct to assess severity ^[3]
  • CRP
  • Fecal calprotectin
  • Fecal lactoferrin
• Evaluation for secondary causes ^[4]
  • Any patient with symptoms suggestive of pouchitis: Obtain a C. difficile assay and gastrointestinal pathogen panel.
  • Patients with chronic pouchitis: Obtain PCR for CMV.

• Crohn disease of the pouch ^[1]
• Cuffitis ^[1]
• Irritable pouch syndrome ^[1]
• Structural pouch disorders, e.g.: ^[3]
  • Pouch stricture
  • Floppy pouch complex (including pouch prolapse)

The differential diagnoses listed here are not exhaustive.

General principles

• Pharmacological treatment is the mainstay of management.
• Dietary modifications (e.g., high intake of fermentable fibers and micronutrients) may help improve symptoms. ^[4]
• Manage triggers (e.g., discontinue NSAIDs).
• Identify and treat causes of secondary pouchitis.

Pharmacological treatment ^[4]

Acute pouchitis ^[4]

• Initial antibiotic therapy: 2-week course of oral ciprofloxacin (preferred) or metronidazole
• Second-line therapy: topical budesonide (e.g., budesonide enema or foam)

Chronic pouchitis

• Induction therapy ^[4]
  • Chronic pouchitis refractory to single antibiotics: combined antibiotics (e.g., ciprofloxacin plus either metronidazole, tinidazole, or rifaximin) for a prolonged course (e.g., 4 weeks)
  • Chronic antibiotic-refractory pouchitis
    • Oral or topical budesonide, especially in patients with pouchitis associated with PSC
    • Advanced therapies: vedolizumab (preferred), anti-TNF agents (e.g., infliximab, adalimumab), or ustekinumab
• Maintenance therapy ^[4]
  • Chronic antibiotic-dependent pouchitis
    • Probiotics for secondary prophylaxis
    • Maintenance antibiotic therapy (e.g., rifaximin)
  • Chronic antibiotic-refractory pouchitis
    • Low-dose oral budesonide in selected patients (e.g., those with pouchitis associated with PSC)
    • Immunomodulators (e.g., mercaptopurine, azathioprine)
    • Topical calcineurin inhibitors (cyclosporine or tacrolimus)

If induction therapy with a biologic is successful, continue the same agent for maintenance therapy. ^[4]

Surgery ^[4]

• May be required for medically refractory disease
• Options
  • Temporary or permanent fecal diversion with an ileostomy
  • Pouch excision

Long-term fecal diversion may cause diversion-related pouchitis, stricture, or neoplasm. ^[4]

Management of secondary pouchitis ^[4]

• C. difficile-associated pouchitis
  • Preferred: oral vancomycin
  • For refractory or recurrent cases: fecal microbiota transplantation
• CMV-associated pouchitis: ganciclovir or valganciclovir
• Ischemia-associated pouchitis: hyperbaric oxygen therapy
• Pouchitis with fecal stasis: treatment of the underlying obstruction (e.g., endoscopic balloon dilation for strictures) or functional cause (e.g., biofeedback for dyssynergic defecation)

• Progression from acute to chronic pouchitis ^[1]
• Crohn disease of the pouch ^[1]
• Prepouch ileitis ^[3]
• Inflammatory polyps ^[4]
• Pouch failure (i.e., permanent stoma required) ^[3]

We list the most important complications. The selection is not exhaustive.