A colovesical fistula is an abnormal connection that develops between the colon and the bladder. It can result from diverticulitis, Crohn’s disease, or another gastrointestinal condition.

Read on to discover what happens when a person has a colovesical fistula, what symptoms they may experience, and what can cause the condition. We also look at the condition’s diagnosis; treatment options, including surgery; and possible complications, as well as when to consult a doctor.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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A diagram of a colovesical fistulaShare on Pinterest
Designer: Diego Sabogal

A fistula is an abnormality between two organ surfaces. Colovesical fistulas, which form between the colon and the bladder, are rare occurrences.

Doctors classify an enterovesical fistula according to the area it affects:

  • Colovesical: colon and bladder
  • Rectovesical: rectum and bladder
  • Ileovesical: ileum and bladder
  • Appendicovesical: appendix and bladder

The colovesical fistula is the most frequent and usually develops between the sigmoid colon and the bladder dome.

The colon is the largest part of the large intestine. It is responsible for removing water and nutrients from partially digested food.

The bladder is a flexible organ that stores urine. When it is not full, the bladder is relaxed. The surrounding muscles contract when the bladder gets full.

On average, a person may develop a colovesical fistula between ages 55 and 75. Males are slightly more at risk of developing the condition than females who have a uterus.


If a person has a colovesical fistula, they may develop some of the following symptoms:

  • Fecaluria — stool in the urinary stream: This is when fecal matter mixes with urine. Urine may appear with brown cloudiness. This symptom is present in 50–70% of people with the condition.
  • Pneumaturia — air in the bladder: This occurs when gas produced in the colon mixes with the urine. This symptom can appear as bubbles in urine. It occurs in 70–90% of people with the condition.
  • Dysuria — painful urination: This is a burning sensation during urination that can result from a urinary tract infection (UTI).
  • Hematuria — blood in urine: This is when traces of blood are present in urine. It is a less common symptom.

Recurrent UTIs and generalized abdominal pain may also indicate that a person has a colovesical fistula.

The most common cause of colovesical fistulas is diverticulitis, which accounts for more than two-thirds of all cases. This condition causes abscesses to form around the colon, which can extend or rupture into an adjacent organ. In the case of colovesical fistulas, this affects the bladder.

Other causes of colovesical fistulas include:

Healthcare professionals use various methods to diagnose and determine the underlying cause of a colovesical fistula:

  • CT scans: These scans are up to 90% accurate. They allow a doctor to see air movement through the abnormal wall between organs.
  • Colonoscopy: In this procedure, doctors insert a microscopic camera into the colon. This method is less accurate than a CT scan but can eliminate any cancerous cause of the fistula.
  • Cystoscopy: In this procedure, medical professionals place a camera into the bladder to see whether a fistula is present.
  • Barium enema: This procedure can help medical professionals identify any problems with the colon. Water containing barium, a metal, coats the inside of the rectum. An X-ray allows a doctor to see more detail than a standard imaging tool.

Assessment of these images, a physical exam, urine testing, and a general review of symptoms can help a medical professional diagnose a colovesical fistula.

Doctors may perform surgery or use more conservative treatments for a colovesical fistula. Some people, including those with terminal cancer, will not be suitable candidates for surgery.

The purpose of conservative treatments is to allow the fistula to heal itself. These treatments typically include antibiotics if an infection is present. This medication will also help treat diverticulitis or Crohn’s disease if either condition is the cause of the fistula.

Doctors may also recommend that a person eat more dietary fiber to help soften stool and relieve symptoms of diverticulitis.

Learn more about the diverticulitis diet.

Treatment for Crohn’s disease may include medication, dietary changes, or supplements. Treatment aims to:

  • relieve inflammation
  • reduce the occurrence of flares
  • improve nutrition and food absorption

Read more about Crohn’s disease treatments.

Surgical procedures

If conservative measures are not successful, a person may still need surgery to avoid further complications.

A surgeon can remove the fistula and repair the damage between organs to stop the exchange of fluids.

The standard treatment of colovesical fistula involves:

  • removal of the fistula
  • closure of the bladder wall
  • colic resection with or without temporary colostomy, in some cases

Doctors will determine the type of surgery based on the location of the colovesical fistula.

For example, the most common location is between the sigmoid colon and the bladder. Therefore, surgeons often perform a procedure called a sigmoid colectomy. This involves removing all or some of the sigmoid colon — the last part of the colon. Doctors remove the fistula and patch up the bladder and colon.

They may perform this as open surgery, which involves a single large incision, or as laparoscopy, which involves a series of small incisions. However, as older research suggests, doctors reserve the latter type for select cases. Because of possible complications, it is not yet the treatment of choice.

A person who has undergone colovesical fistula removal surgery should expect to have a catheter for 7–10 days afterward.

A 2018 study found that the average hospital stay was 8 days.

People should follow their healthcare team’s guidance on post-surgery limitations, such as refraining from heavy lifting or driving. A person may also need to continue taking antibiotics if pain or symptoms persist.

It is common for a person who has undergone this surgery to temporarily follow a liquid diet after the procedure to allow the intestines to rest.

Learn more about fistula surgery recovery.

Colovesical fistulas are rare abnormalities that can develop due to other conditions, surgical procedures, or abdominal traumas.

A doctor will use various diagnostic methods to determine why a person is experiencing related symptoms.

This condition is treatable depending on the specifics of the fistula, such as the location and the cause.