Can Diverticulitis Cause Blood In The Urine? | When To Worry

Blood in urine isn’t a usual diverticulitis symptom, but a flare can line up with a UTI, a stone, or a rare colon-to-bladder fistula that irritates the bladder.

Seeing pink, red, or tea-colored urine can feel like a gut punch. If you also have left-side belly pain, fever, or you were told you have diverticulitis before, it’s natural to connect the dots.

Most of the time, diverticulitis isn’t the direct cause of blood in urine. When hematuria shows up, it often points to a separate urinary problem happening at the same time. The point of this guide is simple: help you spot the most likely routes, get the right tests, and know when you should get care right away.

What Blood In Urine Usually Means

Hematuria can be visible (you can see it) or microscopic (found on a urine test). It can start anywhere along the urinary tract: kidneys, ureters, bladder, prostate (in men), or urethra.

Common causes include UTIs, kidney or bladder stones, an enlarged prostate, and certain medicines. Kidney disease and urinary tract cancers are less common, but they’re part of the reason clinicians take hematuria seriously. A clear overview of causes and standard testing is on NIDDK hematuria (blood in the urine).

What “Visible” Versus “Microscopic” Changes In Practice

Visible blood gets attention because it’s harder to dismiss. Microscopic blood can show up in routine labs even when you feel fine. Both can be real, and both can come and go, which is why a single “normal” day doesn’t always close the case.

Color alone can mislead. Foods like beets and some drugs can tint urine. A urinalysis is the quick way to confirm if it’s true blood. If you can, collect a sample before you take antibiotics, since treatment can change test results.

How Diverticulitis Can Affect Urinary Symptoms

Diverticulitis is inflammation and sometimes infection in small colon pouches. Typical signs include left lower belly pain, fever, nausea, and bowel habit changes. Diagnosis and treatment often involve an exam, labs, and imaging like CT. Mayo Clinic summarizes common evaluation steps on its page for diverticulitis diagnosis and treatment.

The colon and bladder sit close together. During a flare, swelling near the bladder can make you feel urinary urgency, pelvic pressure, or burning. Those symptoms can mimic cystitis. Still, irritation by itself rarely explains blood in urine.

Uncomplicated And Complicated Flares

Clinicians often group diverticulitis into “uncomplicated” and “complicated.” Uncomplicated flares involve inflammation without abscess, blockage, perforation, or fistula. Complicated cases can include an abscess (a pocket of pus), a perforation, or a fistula. The closer the inflamed segment is to the bladder, the more likely urinary symptoms show up.

If you’ve had repeated flares, or you’ve been told you had an abscess in the past, the odds of urinary complications rise. That doesn’t mean blood in urine is expected. It means you should be checked with the same seriousness you’d use for any hematuria.

Can Diverticulitis Cause Blood In The Urine? What To Know

Yes, it can, but the link is usually indirect. In practice, there are three common routes behind most “diverticulitis plus hematuria” stories.

A UTI Overlapping A Flare

UTIs can cause burning, frequent urination, pelvic pressure, and blood in urine. If belly pain is already present, urinary symptoms may get brushed off as “part of the flare.” That can delay testing and delay the right treatment.

A simple urinalysis can show signs of infection, like white blood cells and bacteria. A urine culture can confirm the organism and help pick the right antibiotic if symptoms keep returning.

A Kidney Or Bladder Stone

Stones often cause blood in urine, sometimes with sharp wave-like pain that can move from the side or back toward the groin. Some people get nausea or vomiting. Others just feel urgency and see blood.

A flare can line up with stones because people often drink less and eat differently when they feel ill. Concentrated urine makes crystals more likely to clump. If you’ve had stones before, mention it early in the visit, since it changes which imaging is most useful.

A Colovesical Fistula

A colovesical fistula is an abnormal connection between the colon and bladder. Diverticulitis is a leading cause in adults. It usually forms after repeated inflammation sticks the colon to the bladder. Over time, the wall can break down and create a passage between the two organs.

Clues that push fistula higher on the list include:

• repeated UTIs that keep coming back soon after treatment
• air bubbles in urine (pneumaturia)
• fecal smell or debris in urine (fecaluria)
• urinary burning that returns again and again

Hematuria can occur with a fistula, often tied to infection and bladder irritation. Cleveland Clinic notes that diverticulitis can lead to complications, including abscesses and fistulas, on its patient overview page: Diverticulitis (Cleveland Clinic).

Clues That Help You And Your Clinician Connect The Dots

These details help narrow the cause and speed up the right tests:

• Timing: Did urine changes start during the flare, or before belly symptoms?
• Pain pattern: Steady left-lower pain fits diverticulitis; wave-like moving pain fits stones.
• Urinary signs: Burning and urgency fit UTI; pneumaturia or fecal odor raise fistula concern.
• Clots: Clots often suggest bleeding closer to the bladder or urethra.
• What you see in the toilet: Blood that appears only at the start or end of urination can hint at a lower tract source.

People sometimes assume one flare explains all symptoms. Reality is messier. It’s possible to have diverticulitis and a urinary problem at the same time, and you don’t want to miss either.

Scenario	Clues You Might Notice	What Clinicians Often Check
Diverticulitis with urinary irritation	Left lower belly pain; urgency without strong burning	Urinalysis; CT when diagnosis is uncertain
UTI overlapping a flare	Burning; frequent urination; cloudy urine; sometimes fever	Urinalysis and urine culture
Kidney or bladder stone	Wave-like flank/groin pain; nausea; blood in urine	Urinalysis; CT or ultrasound
Colovesical fistula	Repeated UTIs; pneumaturia; fecaluria	CT with contrast; cystoscopy; colon evaluation later
Kidney infection	Fever; chills; back pain; vomiting	Urine tests; blood work; imaging if severe
Kidney disease source	Foamy urine; swelling; tea-colored urine	Urine microscopy; kidney labs
Bladder or kidney growth	Painless hematuria; risk rises with age and smoking history	Urology evaluation; imaging; cystoscopy
Medication or blood thinner effect	New hematuria after medication change; easy bruising	Medication review; urine test; rule-out other causes

What Testing Often Looks Like

Most visits start with urinalysis. It checks for red blood cells, white blood cells, bacteria, protein, and crystals. If your urine shows white blood cells or nitrites, infection moves up the list. If it shows many crystals, stones move up.

How Imaging Choices Get Made

Imaging depends on symptoms and risk. If you’re being checked for diverticulitis, a CT scan may already be part of the plan, and it can also spot stones, abscesses, kidney swelling, or signs of fistula. Ultrasound is used in some settings, especially for kidney swelling and for people where limiting radiation matters.

When Urology Gets Involved

If blood persists or keeps returning, clinicians often follow risk-based tracks for further evaluation. The American Urological Association lays out who may need cystoscopy and what imaging fits different risk levels in its AUA/SUFU microhematuria guideline.

Cystoscopy sounds intimidating, but it’s a short procedure that lets a clinician view the bladder lining. It can find bleeding sources that won’t show on a urine test alone.

What A Urine Test Can Show In Minutes

A dipstick can flag blood quickly, then microscopy counts red blood cells and checks their shape. White blood cells and nitrites point toward infection. Crystals can hint at stones. Protein plus blood can point toward a kidney source, which may shift the workup toward kidney labs and a nephrology visit.

When To Get Same-Day Care

If any of the items below fit, seek same-day evaluation at urgent care or an emergency department:

• visible blood in urine plus fever, chills, or shaking
• flank pain with vomiting or inability to keep fluids down
• blood clots or urine that turns bright red
• faintness, weakness, or heavy sweating
• pregnancy, a single kidney, or known kidney disease

Red Flag	Why It Matters	What You’ll Likely Get First
Fever plus urinary burning	Can fit a kidney infection	Urine test, blood work, antibiotics
Severe flank pain plus blood	Stone can block urine flow	Pain control, imaging, urine tests
Visible clots	Bleeding may be lower in the tract	Urine test, imaging, urology input
Air bubbles or fecal smell in urine	Raises concern for fistula	CT imaging, surgical or urology evaluation
Confusion or low blood pressure	Can fit severe infection	IV fluids, labs, antibiotics, monitoring

How To Prepare For Your Visit

A little prep can save time and reduce repeat visits:

• Note the start time, whether it comes and goes, and any clots.
• Write down recent antibiotics, blood thinners, and new medicines.
• List your diverticulitis history: first flare, recent flares, any abscess, any prior CT results.
• Describe the pain: steady, wave-like, left side, or flank.
• Bring up pneumaturia or fecaluria right away if you’ve noticed it.

What Most People Learn After Testing

Most people with diverticulitis and hematuria end up finding a urinary cause that overlapped with the gut flare. That’s still useful: once the cause is pinned down, treatment can be targeted and the guessing stops.

If tests show infection, finish the full course of antibiotics and ask whether a follow-up urine test is needed. If stones are found, ask what size they are and whether you need a repeat scan. If the workup is negative but hematuria returns, don’t brush it off. Bring the timeline and test history back to your clinician and ask what the next step is.