Skip to Main Content

We have a new app!

Take the Access library with you wherever you go—easy access to books, videos, images, podcasts, personalized features, and more.

Download the Access App here: iOS and Android. Learn more here!

  • Fistula: Communication between 2 epithelialized surfaces

    • Colovesical fistula

    • -Most common communication between bladder and GI tract

      -Diverticulitis is most common cause

      -Refractory, recurrent urinary tract infection (UTI) is common presentation

    • Classified by output

    • -High output > 500 mL/d

      -Low output < 500 mL/d

    • Most common causes include:

    • -Prior abdominal operation, especially for inflammatory bowel disease


      -Extensive adhesions


      -Anastomotic leaks

      -Diverticular disease



      -Foreign body

    • Malnutrition also major risk factor in fistula formation/failure to heal


  • • Affects more men than women (3:1)

    • Complicates 2-4% cases of diverticulitis

    • 67-80% fistulas follow abdominal surgery

Symptoms and Signs

  • Colovesical fistula

    • -Patients may be asymptomatic

      -Patients may have chronic, refractory UTI and present with fecaluria, pneumaturia

      -Physical exam usually not revealing

      -Patient may show signs of dehydration

    Colocutaneous fistula

    • -Draining sinus at the skin with enteric content or stool

      -Often located at wound or incision with surrounding erythema, excoriation, induration

Laboratory Findings

  • • No pathognomonic abnormalities

    • UA may reveal fecaluria, infection

    • Low serum albumin, prealbumin, transferring indicative of compromised nutritional status

Imaging Findings

  • Sigmoidoscopy is usually unrevealing, though may disclose inflammation or mass at the fistula site

    Cystoscopy usually fails to visualize opening

    CT may detect small amounts of air in bladder

    Contrast enema may demonstrate large fistulas but commonly misses small openings

    Fistulogram if tract is mature

    Pyelography and cystography may be used to discern connection with urinary tract

  • • Consider etiology of fistula formation and reasons for failed closure (eg, foreign body, radiation injury, abscess, distal obstruction, neoplasm, inflammatory conditions, epithelialization)

Rule Out

  • • GI malignancy or primary bladder malignancy as cause of fistula

  • • UA

    • CT scan to evaluate for location of fistula, possible source (eg, sigmoid diverticulitis, mass, abscess)

    • Obtain nutrition status markers

    • -Serum albumin



    • Endoscopic evaluation of GI tract, bladder

When to Admit

  • • Severe nutritional depletion

    • Septic complications

    • Severe dehydration

  • • Persistent fistulae require surgical intervention, although no need for urgent or emergent surgery

    • Up to 50% of colovesical fistulas secondary to diverticulitis close spontaneously

    • Treat volume loss with adequate fluid resuscitation

    • Correct electrolyte abnormalities

    • Improve nutritional status (low output, distal fistulas may be treated with enteral feeding); use total parenteral nutrition if high output or intolerance to enteral feeding

    • Sepsis must be aggressively addressed early

    • Drain abscesses

    • IV antibiotics when infection present

    • Open, debride, and pack infected wounds

    • Control and measure fistula output

    • Protect skin surrounding cutaneous fistula opening



  • • Recurrent UTI

    • Failure to close spontaneously


Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.