Yes, diverticulitis can cause urinary problems, ranging from mild bladder irritation to serious complications like an abnormal connection between the colon and bladder. The sigmoid colon, where diverticulitis most commonly occurs, sits right next to the bladder. When the colon wall becomes inflamed, that inflammation can spread to the bladder and produce symptoms that feel a lot like a urinary tract infection.
Why Diverticulitis Affects the Bladder
The sigmoid colon and the bladder are neighbors in your lower abdomen, separated by only a thin layer of tissue. When a diverticular pouch becomes infected and swollen, the inflammation doesn’t stay neatly contained. It can press against or directly irritate the bladder wall, causing urinary urgency, frequent urination, and pain or burning when you urinate. Some people experience these urinary symptoms before they even realize diverticulitis is the underlying cause.
This proximity also explains why diverticulitis is sometimes initially misdiagnosed as a urinary tract infection. Both conditions can produce overlapping symptoms: pelvic pain, burning urination, and blood in the urine. The distinguishing clue is usually the presence of lower-left abdominal pain and fever alongside the urinary complaints, which points toward an intestinal source rather than a bladder-only problem.
Colovesical Fistula: The More Serious Complication
In some cases, the inflamed colon wall erodes through into the bladder, creating an abnormal tunnel called a colovesical fistula. This is the most significant urinary complication of diverticulitis. When the colon and bladder are connected this way, intestinal contents can leak into the urinary tract, causing persistent infections and unusual symptoms you wouldn’t expect from a typical UTI.
The hallmark signs of a colovesical fistula are air bubbles in the urine (pneumaturia) and fecal matter in the urine (fecaluria), usually noticed at the end of urination. Pneumaturia shows up in roughly 70% to 90% of people with this complication, while fecaluria occurs in 50% to 70%. Passing air or stool through your urinary stream is considered virtually diagnostic of this condition, meaning if it happens, a fistula is almost certainly the explanation.
Men develop colovesical fistulas from diverticulitis at two to three times the rate women do. The reason is anatomical: in women, the uterus sits between the sigmoid colon and the bladder, acting as a physical buffer that makes direct erosion less likely.
How It’s Diagnosed
If your doctor suspects diverticulitis is causing your urinary symptoms, a CT scan is the primary tool. CT imaging detects colovesical fistulas with roughly 90% accuracy, making it the most reliable noninvasive option. It can reveal inflammation near the bladder, air inside the bladder that shouldn’t be there, and sometimes the fistula tract itself. That said, very small fistulas can be missed on CT, so a scope inserted into the bladder (cystoscopy) or colon (colonoscopy) may be used as follow-up when suspicion remains high despite a normal scan.
Urine tests often show bacteria or blood, which can initially steer the workup toward a straightforward UTI. The key red flag is a UTI that keeps coming back despite proper treatment, or one that involves unusual bacteria typically found in the gut rather than the urinary tract. Recurrent UTIs in someone with a history of diverticulitis should raise the question of a fistula.
Treatment for Bladder Irritation vs. Fistula
When diverticulitis simply irritates the bladder without creating a fistula, the urinary symptoms typically resolve once the diverticulitis itself is treated. Antibiotics to clear the intestinal infection and reduce inflammation are usually enough, and the bladder irritation fades as the flare settles down.
A colovesical fistula is a different situation. Fistulas don’t close on their own reliably, so surgery is the standard treatment. The procedure involves removing the diseased section of colon and repairing the hole in the bladder wall. When performed using minimally invasive techniques, patients typically regain bowel function within about two days and go home within six days, though the range can extend to nearly two weeks depending on complexity. In studies tracking patients for over a year after surgery, recurrence of both diverticulitis and fistula was zero, which is reassuring.
For people who aren’t good candidates for surgery due to age or other health conditions, long-term antibiotics can manage the infections caused by the fistula, but this approach controls symptoms rather than fixing the underlying problem.
Symptoms That Warrant Attention
Mild urinary urgency during a known diverticulitis flare isn’t unusual and generally resolves with treatment. But certain symptoms suggest something more significant is going on:
- Air bubbles in your urine, especially at the end of the stream
- Cloudy or foul-smelling urine with visible particles
- Recurrent UTIs that clear with antibiotics but keep returning
- Lower abdominal pain that worsens with urination
Any combination of urinary symptoms and left-sided abdominal pain deserves evaluation, particularly if you have a history of diverticular disease. The sooner a fistula is identified, the more straightforward the repair tends to be.