What is Colovesical Fistula (Abnormal Connection Between the Colon and the Bladder)?
A fistula is an abnormal connection between two areas with skin linings. The name of the fistula is usually based on the organs it connects. For example, if it connects the bladder and the colon, it’s called a “colovesicular fistula”. Knowing the complex structure of the pelvis and its organs aids doctors in understanding this condition and planning appropriate treatments.
Looking at the anatomy, we start with the Sigmoid Colon. This is part of the large intestine which is inside the pelvic area. Compared to other parts of the large intestine, the sigmoid colon can move around a bit more. It’s about 15 to 50 cm long, averaging at 38 cm. Where it changes into the rectum is known as the rectosigmoid junction, which is located at the level of the sacral promontory or where the taeniae (bands of muscle) meet. A tissue layer called Denonvilliers’ fascia separates the rectum from the prostate or seminal vesicles in men, and from the vagina in women.
When we look further into the colon, we see four layers:
1. Mucosa: This innermost layer is made of columnar epithelium cells.
2. Submucosa: This layer contains most of the collagen in the bowel wall and provides strength.
3. Muscularis Propria: This muscle layer has inner circular and outer longitudinal layers. The outer longitudinal layer forms three bands (taenia coli) on the colon.
4. Serosa: The outermost layer.
The blood supplying the rectum and sigmoid colon primarily comes from the inferior mesenteric artery (IMA). This artery supplies blood to the ascending colon, sigmoid colon, and the beginning part of the rectum. The smaller branches of these arteries join with other nearby branches.
Next, we have the urinary bladder, which is placed in an area called the retropubic space (Retzius) and is considered extra-peritoneal. For men, the posterior bladder wall sits next to the anterior sigmoid colon and rectum. For women, the top of the bladder touches the lower uterus, and the base of the bladder is close to the front part of the vaginal wall. The uterus separates the colon from the bladder making fistulas between them much less common in females.
Finally, we have the ureters, the tubes that run from the kidneys to the bladder. These start at the renal pelvis, run past the psoas muscle, and then move towards the center when they cross the iliac vessels near where they split. They then run along the side of the pelvis and pass under the uterine artery in women before entering the bladder from the side.
What Causes Colovesical Fistula (Abnormal Connection Between the Colon and the Bladder)?
Fistulas, or abnormal connections between two body parts, can be caused by several things. A simple way to remember these causes is with the acronym FRIENDS: Foreign body, Radiation, Inflammatory Bowel Disease, Epithelialization, Neoplasm (cancer), Distal obstruction, and Sepsis (infection).
The most common cause of fistulas between the colon and bladder is a complication of a condition called diverticulitis and this accounts for over two-thirds of cases. The next most common cause is colon cancer, which accounts for about 10% to 20% of cases. Crohn’s disease, which is a type of Inflammatory Bowel Disease, is the third most common cause, accounting for 5% to 7% of cases, and typically occurs as a result of the disease being present for a long time.
Other less common causes of these fistulas are accidents during surgery or procedures, exposure to pelvic radiation, trauma to the abdomen, and tuberculosis (TB).
Risk Factors and Frequency for Colovesical Fistula (Abnormal Connection Between the Colon and the Bladder)
Diverticular disease is a common problem in western societies. It often leads to the formation of colovesicular fistulas, which are abnormal connections between the colon and bladder. This condition mostly affects older people, with a 30% risk in those above 60 years and up to 70% risk in those over 80 years. Out of everyone who has diverticulosis, about 15% to 25% will experience diverticulitis in their lifetime, though a 2013 study puts this risk at 4%.
- Diverticular disease is a frequent issue in western societies.
- People over 60 have a 30% chance of getting diverticulosis, which can lead to colovesicular fistulas. The risk increases to 70% for people over 80.
- About 15% to 25% of people with diverticulosis will have diverticulitis at some point, though a 2013 study found the risk to be only 4%.
- The chance of developing a colovesicular fistula when you have diverticular disease ranges from 2% to 23%.
Usually, people with colovesicular fistulas are aged between 55 and 75. The condition is more common in males, mainly because females have a uterus. However, many females who develop colovesicular fistulas have undergone a hysterectomy.
- The typical age for diagnosing colovesicular fistulas is between 55 and 75.
- The condition is commonly found in males because females have a uterus providing a protective effect.
- Many females who get colovesicular fistulas have previously had a hysterectomy.
Signs and Symptoms of Colovesical Fistula (Abnormal Connection Between the Colon and the Bladder)
Patients with a condition known as CVF commonly experience recurrent urinary tract infections. This is often the third most common symptom. They might also experience pneumaturia and/or fecaluria, which are fancy terms for air or stool in their urine, usually towards the end of urination. Approximately 70% to 90% of patients with CVF experience pneumaturia, and about 50% to 70% experience fecaluria. These symptoms are almost unique to CVF, so if a patient has these, the doctor will usually check for other causes related to the bladder or certain types of urinary tract infections.
Less common symptoms include painful urination, blood in the urine, a constant need to urinate, frequent urination, and pain in the lower part of the belly. However, less than 50% of CVF patients who have diverticulitis reported having a history of this particular disease.
- Recurrent urinary tract infections
- Pneumaturia (air in urine)
- Fecaluria (stool in urine)
- Painful urination (dysuria)
- Blood in the urine (hematuria)
- Constant need to urinate (urgency)
- Frequent urination
- Pain in the lower part of the belly (suprapubic pain)
Testing for Colovesical Fistula (Abnormal Connection Between the Colon and the Bladder)
The main aim of assessing patients is to confirm what is wrong and find the root cause of their condition. Usually, a CT scan and a lower endoscopic examination are done to help identify the issue.
The CT Scan
CT scan, which involves swallowing or receiving rectal contrast material instead of intravenous contrast, is the first and best test for this. More than 90% of the time, this test can successfully identify any issues. It will show if there is any contrast material or air in the bladder, as well as if the walls of the colon and vesicle are thickening. While the scan may not always show the fistula tract (an abnormal connection between organs), it can predict the location accurately. It’s also good for drawing up a map of the anatomy, identifying tumors, and helping to discover the root cause of the problem.
Colonoscopy
A colonoscopy test isn’t as sensitive (11% to 89%), meaning it isn’t as effective at identifying the fistula tract. However, it is useful to exclude the possibility of cancer before surgical operations.
Cystoscopy
This test has an even lower sensitivity (less than 50%) compared to a CT scan in identifying a communication between the bladder and intestines (CVF). Doctors might not see the fistula tract during this test, but they may find edema or swelling at the site. It’s indicated when there’s suspicion of a dangerous bladder fistula, such as when there’s a history of bladder cancer, a bladder mass identified in a CT scan, or lack of colonic pathology.
Barium Enema
A barium enema is not as commonly used today, with CT scans and endoscopies often taking its place. However, it can be useful in diagnosing CVF (though it only has 30% sensitivity) and finding the root cause, such as colon cancer or diverticulosis (where small bulges develop in the lining of the large intestine).
Poppy Seed Test
In this test, the patient eats poppy seeds, and their urine is checked after 48 hours. It can identify CVF 100% of the time but doesn’t give much information about the location of the disease or the root cause.
MRI
The MRI scan is helpful for complex fistulas in patients with Crohn’s disease, though it’s more expensive than a traditional X-ray.
Treatment Options for Colovesical Fistula (Abnormal Connection Between the Colon and the Bladder)
If there are signs of infection, it’s important to treat the patient with antibiotics.
When surgery isn’t a good option, like for patients who are too ill or those with widespread cancer that can’t be removed, a couple of approaches can be considered:
– Conservative treatment: Before, it was believed that not operating could lead to serious complications like blood poisoning and even death. However, recent studies show that avoiding surgery can be safe and cause little harm or discomfort to the patient.
– Experimental treatments like injecting the fistula (an abnormal connection between organs) with a special type of glue or inserting a colonic stent (a device to hold the colon open) have also been tried with some success.
For those healthy enough for surgery, the best option is usually to repair the fistula, either through traditional open surgery or minimally invasive surgery.
Most patients can have all parts of their operation done in one stage, meaning they wouldn’t need multiple surgeries. This procedure can involve moving the left colon, separating the colon from the bladder, injecting dye into the bladder to find the hole and repairing it if necessary, removing the diseased part of the colon, and using the omentum (part of the abdominal tissue) to keep the bladder and colon from sticking together. Debris in the bladder and lymph nodes may need to be removed if this is all due to cancer.
However, certain patients at high risk for complications might require staged operation. This would start with the same surgery as mentioned above, followed by either a temporary bag for stool or a colostomy (procedure to bring part of the colon to the surface of the abdomen). The second stage would be the reversal of the bag or colostomy. In rare cases, a third step may be necessary to reverse a temporary bag at a later date.
After surgery, all patients will need a bladder catheter for about 7-10 days.
Using an ostomy (procedure that creates an opening in the body for the discharge of body wastes) to steer stool away from the fistula is generally not preferred because it hasn’t been very successful, often leads to urinary tract infections, and results in high rates of the condition coming back.
What else can Colovesical Fistula (Abnormal Connection Between the Colon and the Bladder) be?
There are a few other conditions that can cause air bubbles in your urine, known as pneumaturia. These include:
- Recent medical procedures involving the bladder, which you will know from your medical history
- A urinary tract infection (UTI) caused by a type of bacteria that forms gas. This is more common in people with diabetes or blockages in the urinary tract. An image of your bladder wall may show air bubbles. Doctors usually treat this with antibiotics based on your urine test results.
To treat a condition known as colovesicular fistula (an abnormal connection between your colon and bladder), doctors first need to understand what’s causing it. They start with a CT scan of your stomach area, followed by a colonoscopy (a procedure to examine the inside of your colon). If there’s reason to suspect bladder cancer, they will examine your bladder using a procedure called a cystoscopy.
What to expect with Colovesical Fistula (Abnormal Connection Between the Colon and the Bladder)
The future outcome for patients with colovesicular fistulas (abnormal connections between the bladder and colon) typically depends on the cause of the condition. The most common cause, benign diverticular disease, usually has a positive outcome. Recent studies have found that there’s little to no difference in rates of blood poisoning, kidney failure, and death rates when comparing surgery with non-surgical, conservative treatment options.
Complications related to diverticular disease such as abscess, fistula formation, strictures, and perforation, are associated with a higher risk of colon cancer. Patients with straightforward diverticulitis have a 3% to 5% chance of having cancer, while those with complicated diverticulitis have about an 11% chance.
Patients suffering from symptomatic diverticular disease should undergo a colonoscopy once their acute infection clears up. This is particularly important for complicated cases. It was previously believed that patients with repeated episodes of uncomplicated diverticulitis were more likely to have more severe disease in the future. However, recent research shows that patients tend to have more severe diverticulitis with their first episode and the risk decreases with each recurrent episode. Elective colon resection (removal of a part of the colon) is recommended for complicated diverticulitis, as it has a high recurrence rate of up to 40%. The reasons for choosing an elective sigmoidectomy are a subject of ongoing debate.
Possible Complications When Diagnosed with Colovesical Fistula (Abnormal Connection Between the Colon and the Bladder)
After having an elective colon resection, a surgery typically done to treat conditions like colovesicular fistula, some patients may face certain complications. Here are a few possible outcomes:
- Death: This is very rare, occurring in only about 1% to 2.3% of cases
- Health complications: This is more common, with reports varying from 6.4% to 49%, but most often around 19%
- Recurrence: This refers to the original problem coming back; it’s seen in about 2.6% to 12.5% of patients
Recovery from Colovesical Fistula (Abnormal Connection Between the Colon and the Bladder)
The patient should keep the Foley catheter in for about 7 to 10 days. Meanwhile, numerous healthcare centres worldwide are now using improved recovery programs after surgery. These new programs have proven to be safe and even reduce the average hospital stay. For example, people who have elective colon resections now typically only stay in the hospital for 3 days.