Diverticulosis is one of the most common findings on colonoscopy in adults over 50. It is also one of the most commonly dismissed. A typical scenario plays out like this: a patient undergoes colonoscopy for evaluation of chronic abdominal pain and bloating. The gastroenterologist finds diverticula in the sigmoid colon, notes them in the report, and tells the patient their colonoscopy was "otherwise normal." The chronic symptoms are attributed to IBS. The diverticula are treated as incidental. But in patients with symptomatic uncomplicated diverticular disease (SUDD), those diverticula are not incidental. They are the structural basis for chronic pain, bloating, and altered bowel habits that have been mislabeled as a functional condition.
Why does diverticular disease get misdiagnosed as IBS?
The misdiagnosis happens for three connected reasons. First, diverticulosis is so common in older adults that clinicians often regard it as a normal age-related finding rather than a potential cause of symptoms. A colonoscopy report noting "scattered diverticula in the sigmoid colon" does not automatically trigger a SUDD evaluation. Second, SUDD is a relatively recent diagnostic concept. The term was formalized in international consensus statements only in the last decade. Many clinicians trained before SUDD was widely recognized may not consider it as a distinct entity separate from uncomplicated diverticulosis. Third, the symptoms of SUDD and IBS are so similar that without imaging context, they are clinically indistinguishable. A patient who meets Rome IV criteria for IBS and who also has diverticulosis could have IBS, SUDD, or both. Without specifically evaluating the relationship between structural findings and symptoms, the IBS label gets applied by default.
SUDD vs IBS: the clinical overlap
Cuomo and colleagues published a study examining the overlap between SUDD and IBS and found that distinguishing the two based on symptoms alone is not reliably possible. Both conditions produce recurrent abdominal pain, bloating, altered stool frequency and form, and symptom fluctuation over time. Both can involve periods of remission and relapse. Both are associated with reduced quality of life and increased healthcare utilization.
The shared pathophysiology strengthens the overlap. Both SUDD and IBS involve visceral hypersensitivity (increased pain perception from normal gut stimuli), altered colonic motility, changes in gut microbiome composition, and low-grade mucosal inflammation (demonstrated in tissue biopsies from both conditions). Some researchers have proposed that SUDD and IBS may represent different points on a shared spectrum rather than truly separate diseases. This academic debate does not change the practical clinical question: if you have diverticula and symptoms, are the diverticula contributing?
Clinical scenarios where diverticular disease is missed
- The incidental finding scenario. Diverticulosis is found on colonoscopy performed for IBS evaluation. The report says "diverticulosis noted, otherwise unremarkable." The patient is told they have IBS. No one specifically evaluates whether the diverticula correlate with the symptom location and pattern. The structural finding and the symptoms are never connected.
- The age-dismissal scenario. A patient over 60 presents with chronic left lower quadrant pain and bloating. Because IBS is common and diverticulosis is expected for their age, symptoms are attributed to IBS. The possibility that diverticular disease is driving the symptoms is not specifically investigated because diverticulosis is considered "normal" at that age.
- The post-diverticulitis scenario. A patient recovers from an episode of acute diverticulitis treated with antibiotics. Weeks later, they continue to have abdominal pain, bloating, and irregular bowel habits. The acute infection has resolved on follow-up imaging. The persisting symptoms are attributed to IBS rather than being recognized as post-diverticulitis IBS, a condition with its own management considerations.
- The diffuse pain scenario. Some patients with diverticular disease have pain that is not strictly localized to the left lower quadrant. Pain can radiate, be perceived more centrally, or fluctuate in location. When the pain pattern does not fit the classic left-sided diverticular presentation, clinicians are less likely to attribute it to diverticular disease even when imaging shows significant diverticular changes.
How age factors into the diagnostic picture
Age is one of the most practical tools for distinguishing IBS from diverticular disease. IBS typically presents before age 50, often in the 20s-40s. The Rome IV criteria explicitly note that new onset of IBS-like symptoms after age 50 should prompt evaluation for organic causes, including diverticular disease, colorectal cancer, and microscopic colitis. Diverticular disease prevalence increases substantially with each decade after 40.
This does not mean that someone over 50 cannot have IBS or that someone under 50 cannot have diverticular disease. Both scenarios occur. But the pretest probability shifts with age. A 35-year-old with chronic diffuse abdominal pain and no red flags is more likely to have IBS. A 62-year-old with new-onset chronic left lower quadrant pain deserves imaging to evaluate for diverticular disease before IBS is diagnosed.
âšī¸The Rome IV criteria consider new-onset IBS-like symptoms after age 50 to be a reason for additional diagnostic evaluation. If you developed chronic abdominal pain, bloating, or altered bowel habits for the first time after age 50 and were diagnosed with IBS without imaging, it is reasonable to ask about CT or colonoscopy evaluation.
Left-sided vs diffuse pain: why location matters
Pain location is the single most useful symptom-level differentiator between diverticular disease and IBS. The sigmoid colon, where most diverticula form, occupies the left lower quadrant of the abdomen. SUDD pain is characteristically felt in this area. It may be described as cramping, aching, or pressure-like. It often worsens after meals and may improve after a bowel movement.
IBS pain is typically more variable in location. It may be felt across the lower abdomen, in the periumbilical region, or shift between areas. While IBS pain can certainly occur in the left lower quadrant, it is less consistently localized there. A patient whose pain is predominantly and consistently in the left lower quadrant should have diverticular disease specifically evaluated as a potential cause, particularly if they are over 50 and have confirmed diverticulosis on prior imaging.
What to ask your doctor
If you have been diagnosed with IBS and suspect diverticular disease may be contributing, these questions can advance the conversation.
- "My colonoscopy report showed diverticulosis. Could those diverticula be causing my chronic symptoms rather than IBS?" This directly asks the clinician to evaluate the relationship between structural findings and symptoms.
- "My pain is consistently in my left lower abdomen. Is that pattern more consistent with diverticular disease than with IBS?" This highlights a key differentiating feature.
- "I am over 50 and these symptoms are relatively new. Should we do a CT scan to evaluate for diverticular disease before assuming this is IBS?" This uses age as clinical context for requesting appropriate imaging.
- "I had an episode of acute diverticulitis last year and my symptoms never fully resolved. Could this be post-diverticulitis IBS?" This names a specific, recognized condition that may warrant different management.
What happens after the diagnosis is corrected?
If diverticular disease is identified as a contributor to symptoms previously attributed to IBS, the treatment approach may shift. SUDD management may include high-fiber diet (to reduce intraluminal pressure and promote regular bowel movements), cyclic rifaximin therapy (7 days per month, which has shown benefit in some SUDD clinical trials), mesalamine (anti-inflammatory, with mixed evidence but some positive trials in SUDD), and lifestyle modifications including regular physical activity and adequate hydration. Acute diverticulitis, if it occurs, requires antibiotics and sometimes hospitalization.
For patients with post-diverticulitis IBS, management may need to address both the structural component (diverticular disease surveillance and prevention of recurrence) and the functional component (visceral hypersensitivity, altered motility). This dual approach is more targeted than treating all symptoms as IBS alone.
Frequently Asked Questions
If my colonoscopy shows diverticulosis, does that mean my symptoms are from diverticular disease?
Not necessarily. Diverticulosis is very common (60% of people over 60) and often asymptomatic. The key question is whether the diverticula correlate with your symptom pattern: specifically, whether your pain is predominantly in the left lower quadrant and whether other features of SUDD are present. Diverticulosis on a colonoscopy report is a finding that requires clinical correlation, not an automatic diagnosis.
Can I have both IBS and diverticular disease at the same time?
Yes. Both conditions are common, and they can coexist. Some patients have diverticular disease contributing to left-sided symptoms and IBS contributing to more diffuse symptoms or visceral hypersensitivity. Identifying both conditions allows for a more targeted treatment approach than labeling everything as IBS.
How is SUDD different from acute diverticulitis?
SUDD involves chronic or recurrent symptoms (pain, bloating, altered bowel habits) in the presence of diverticulosis but without acute inflammation, fever, or elevated inflammatory markers. Acute diverticulitis is an inflammatory/infectious event with sudden severe pain, fever, and elevated CRP or white blood cell count, typically visible as inflammation on CT imaging. SUDD is chronic. Diverticulitis is acute.
Should everyone over 50 with IBS symptoms get a CT scan?
Not automatically. Current guidelines recommend that new-onset IBS-like symptoms after age 50 warrant additional evaluation, which may include colonoscopy and/or CT imaging depending on the clinical picture. If you already have a colonoscopy showing diverticulosis and your symptoms localize to the left lower quadrant, the clinical picture may already support a SUDD evaluation. Discuss imaging decisions with your gastroenterologist based on your specific situation.
Does diverticular disease ever go away?
Diverticulosis itself is permanent. Once diverticula form, they do not resolve. However, SUDD symptoms can be managed effectively, and acute diverticulitis episodes can be treated and prevented. The goal is symptom control and prevention of complications, not reversal of the structural changes.
â ī¸This article is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about a medical condition.